Projeto de Ciência dos Materiais Aplicando o Método Ashby

TAREFA Nesta avaliação você realizará uma atividade de seleção de materiais utilizando o método de Ashby para a sua escolha entre as seguintes opções 2025 páginas no total 1 O cabo de ponte mais leve comprimento especificado capaz de suportar uma tensão S 2 A asa de avião mais leve comprimento e largura especificados com rigidez E 3 Um taco de críquete resistente capaz de suportar uma tensão S 4 Um braço de relé para um interruptor eletromagnético que tenha o menor tempo de resposta possível e que não falhe por fadiga 5 Um material isolante térmico para construção espessura especificada que apresente o menor aumento de temperatura por dia Para o componente escolhido você deve incluir 1 Critérios de projeto incluindo o caso de carregamento e quaisquer premissas que forem feitas Exemplo para um pilar de sustentação de um edifício considerase uma geometria de coluna carregada em compressão com falha por flambagem elástica 2 Objetivos restrições e variáveis livres Dica alguns desses elementos são fornecidos mas cabe a você decidir o que é importante para esta aplicação Lembrese não existe uma resposta certa e sua nota dependerá de quão bem você consegue justificar suas premissas É obrigatório fornecer citações sempre que pertinente 3 Derivação do índice de material 4 Seleção preliminar de materiais utilizando o gráfico de Ashby apropriado 5 Comparação entre materiais utilizando qualquer método apresentado nas aulas exemplo gráfico gonogo classificação de mérito ou parâmetros de propriedades 6 Escolha final do material devidamente fundamentada pela sua análise Como parte da sua seleção você deve considerar a sustentabilidade do seu projeto Inclua comentários sobre 1 A sustentabilidade da sua escolha de projeto ou justificativa para a escolha de um material que tradicionalmente possa não ser considerado sustentável 2 Gestão de recursos como de onde vem o material Como ele é extraído 3 Impacto ambiental incluindo questões de consumo de energia ou emissões relacionadas à produção ou ao uso do material 4 Plano para o fim da vida útil do componente Como parte do relatório você deve incluir um mínimo de 10 citações Essas citações podem apoiar suas premissas de projeto a avaliação dos materiais ou a discussão sobre sustentabilidade Marking Rubric Criteria Level 1 Level 2 Level 3 Level 4 Level 5 Marks 1 Initial Criteria Demonstrate the ability to correctly identify the design criteria objectives constraints and free variables 04 Marks No identification of initial criteria Assumptions are not researched and defended 58 Marks Poor identification of initial criteria Assumptions are minimally researched and defended 912 Marks Adequate identification of initial criteria Assumptions are moderately researched and defended 1316 Marks Good identification of initial criteria Assumptions are well researched and defended 1720 Marks Excellent identification of initial criteria Assumptions are well researched and defended 80 2 Material Index Demonstrate the ability to correctly derive the material index and use the material index to downselect materials on an Ashby chart 02 Marks Incorrect material index provided or no material index and no derivation provided No use of an Ashby chart to downselect materials 34 Marks Incorrect material index provided or no derivation provided Poor use of an Ashby Chart to downselect materials 56 Marks Correct material index identified with an incomplete derivation provided Adequate use of an Ashby Chart to down select materials 78 Marks Correct material index identified with an incomplete derivation provided Good use of an Ashby Chart to down select materials 910 Marks Correct material index identified with a complete derivation provided Excellent use of an Ashby Chart to downselect materials 40 3 Materials Selection Demonstrate the ability to effectively make a material comparison in order to identify the best materials choice 08 Marks No attempt on the materials comparison or selection was made or was limited andor without support or justification 916 Marks The materials comparison and selection were poorly articulated supported andor justified 1724 Marks The materials comparison and selection were somewhat articulated supported andor justified 2532 Marks The materials comparison and selection were clear and wellarticulated supported andor justified 3340 Marks The materials comparison and selection were clear comprehensive and extremely well articulated supported andor justified 160 4 Sustainability Demonstrate the ability to defend the sustainability of your choice and what impact your material has 04 Marks No attempt or discussion was provided or discussion was limited andor without support or justification 58 Marks Sustainability discussion was poorly articulated supported andor justified 912 Marks Sustainability discussion was somewhat articulated supported andor justified 1316 Marks Sustainability discussion was clear and well articulated supported andor justified 1720 Marks Sustainability discussion was clear comprehensive and extremely well articulated supported andor justified 80 5 Writing Style Demonstrate the ability to professionally present the report including intext citation and referencing 02 Marks No attempt at intext citations and referencing andor professional presentation and language were limited Less than 5 citations used 34 Marks Poor demonstration of in text citations and referencing andor professional presentation and language Less than 8 citations used 56 Marks Adequate demonstration of intext citations and referencing andor professional presentation and language At least 8 citations used 78 Marks Good demonstration of in text citations and referencing andor professional presentation and language At least 9 citations used 910 Marks Excellent demonstration of intext citations and referencing andor professional presentation and language At least 10 citations used 40 TASKS In this assessment you will conduct a materials selection activity using the Ashby method for your choice of the following 2025 pages in total 1 The lightest bridge cable length specified capable of withstanding stress S 2 The lightest airplane wing length and width specified with stiffness E 3 A tough cricket bat capable of withstanding stress S 4 A relay arm for an electromagnetic switch which has the minimum response time and will not fail in fatigue 5 A building thermal insulator material thickness specified which has a minimum temperature rise per day For your chosen component you must include 1 The design criteria including the loading case and any assumptions which are made Example a building support column is considered a column geometry which is loaded in compression and fails by elastic buckling 2 Objectives constraints and free variables Hint some of these are provided for you but it is up to you to decide what is important for this application Remember there is no right answer and your marks depend on if you can provide evidence for your assumptions Citations are required where relevant 3 A derivation of the material index 4 A downselection of materials using the correct Ashby chart 5 A material comparison using any method provided in the lectures gonogo chart merit ratings or property parameters 6 A final materials choice which is supported by your analysis As part of your selection you must consider the sustainability of your design You must include comments on 1 The sustainability of your design choice or why it is acceptable to select a material which may not be traditionally considered sustainable 2 Resource management such as where does the material come from How is it harvested 3 Environmental impact including if there are energy or emissions concerns with making or manufacturing with your material 4 A plan for the endoflife of your component As part of your report you must include a minimum of 10 citations These citations may support your design assumptions materials evaluation or sustainability discussion Marking Rubric Criteria Level 1 Level 2 Level 3 Level 4 Level 5 Marks 1 Initial Criteria Demonstrate the ability to correctly identify the design criteria objectives constraints and free variables 04 Marks No identification of initial criteria Assumptions are not researched and defended 58 Marks Poor identification of initial criteria Assumptions are minimally researched and defended 912 Marks Adequate identification of initial criteria Assumptions are moderately researched and defended 1316 Marks Good identification of initial criteria Assumptions are well researched and defended 1720 Marks Excellent identification of initial criteria Assumptions are well researched and defended 80 2 Material Index Demonstrate the ability to correctly derive the material index and use the material index to downselect materials on an Ashby chart 02 Marks Incorrect material index provided or no material index and no derivation provided No use of an Ashby chart to downselect materials 34 Marks Incorrect material index provided or no derivation provided Poor use of an Ashby Chart to downselect materials 56 Marks Correct material index identified with an incomplete derivation provided Adequate use of an Ashby Chart to down select materials 78 Marks Correct material index identified with an incomplete derivation provided Good use of an Ashby Chart to down select materials 910 Marks Correct material index identified with a complete derivation provided Excellent use of an Ashby Chart to downselect materials 40 3 Materials Selection Demonstrate the ability to effectively make a material comparison in order to identify the best materials choice 08 Marks No attempt on the materials comparison or selection was made or was limited andor without support or justification 916 Marks The materials comparison and selection were poorly articulated supported andor justified 1724 Marks The materials comparison and selection were somewhat articulated supported andor justified 2532 Marks The materials comparison and selection were clear and wellarticulated supported andor justified 3340 Marks The materials comparison and selection were clear comprehensive and extremely well articulated supported andor justified 160 4 Sustainability Demonstrate the ability to defend the sustainability of your choice and what impact your material has 04 Marks No attempt or discussion was provided or discussion was limited andor without support or justification 58 Marks Sustainability discussion was poorly articulated supported andor justified 912 Marks Sustainability discussion was somewhat articulated supported andor justified 1316 Marks Sustainability discussion was clear and well articulated supported andor justified 1720 Marks Sustainability discussion was clear comprehensive and extremely well articulated supported andor justified 80 5 Writing Style Demonstrate the ability to professionally present the report including intext citation and referencing 02 Marks No attempt at intext citations and referencing andor professional presentation and language were limited Less than 5 citations used 34 Marks Poor demonstration of in text citations and referencing andor professional presentation and language Less than 8 citations used 56 Marks Adequate demonstration of intext citations and referencing andor professional presentation and language At least 8 citations used 78 Marks Good demonstration of in text citations and referencing andor professional presentation and language At least 9 citations used 910 Marks Excellent demonstration of intext citations and referencing andor professional presentation and language At least 10 citations used 40 Materials Selection for an Electromagnetic Switch Relay Arm A Report on the Application of the Ashby Methodology for Optimized Performance and Fatigue Resistance Your Name Your Student ID Course NameCode Date Executive Summary This report details a systematic materials selection process for a critical component the armature or relay arm of an electromagnetic switch The primary design objective is to minimize the response time of the switch which directly translates to maximizing the operational speed of the relay This objective is subject to the critical constraints that the arm must not fail under cyclic fatigue loading must possess sufficient stiffness to actuate correctly and must function as an electrical insulator The Ashby methodology of materials selection was employed to provide a structured quantitative and transparent approach The relay arm was modelled as a cantilever beam subject to a dynamic point load The objective of minimizing response time was translated into maximizing the arms fundamental natural frequency of vibration Through a rigorous derivation the primary material index for this objective was identified as M Eρ where E is the Youngs Modulus and ρ is the density This index seeks materials that are both stiff and lightweight Additional screening criteria were established including a minimum fatigue strength high electrical resistivity and adequate fracture toughness to prevent catastrophic failure An initial screening process using Ashby charts eliminated metals due to electrical conductivity and many polymers due to low stiffness The optimization process using the derived material index highlighted engineering ceramics high performance polymers and fiberreinforced composites as leading candidate classes Three specific materials were downselected for detailed comparison Alumina Al₂O₃ Polyether ether ketone PEEK and GlassFibre Reinforced Polymer GFRP A weighted property index and qualitative analysis revealed that while Alumina offers the highest theoretical performance index its extreme brittleness low fracture toughness and difficult manufacturability present unacceptable risks for a dynamic component GlassFibre Reinforced Polymer GFRP was selected as the final material choice It provides an outstanding balance of high specific stiffness Eρ excellent fatigue resistance low cost high toughness and manufacturability via molding processes A comprehensive sustainability analysis was also conducted While GFRP is a fossilfuel derived material with endoflife challenges its selection is justified by the operational energy savings of a highperformance longlasting relay and its favorable embodied energy compared to alternatives like ceramics A plan for endoflife management focusing on emerging recycling technologies is also proposed This report concludes that GFRP represents the most robust and wellrounded engineering solution for this demanding application Table of Contents 1 Introduction 11 The Electromagnetic Relay Function and Significance 12 The Role of the Relay Arm 13 The Ashby Materials Selection Methodology 14 Report Objectives and Structure 2 Design Requirements Initial Criteria 21 Function Objective Constraints and Free Variables 22 The Loading Case and Geometric Model 23 Key Assumptions and Justifications 24 Summary of Design Requirements 3 Derivation of the Material Index 31 Translating the Design Objective into a Performance Equation 32 Formulating the Objective Function 33 Isolating Material Geometry and Functional Parameters 34 The Final Material Performance Index 4 Material Screening and DownSelection using Ashby Charts 41 Stage 1 Screening with Hard Constraints 411 Electrical Resistivity 412 Fatigue Strength 413 Service Temperature 42 Stage 2 Optimization using the Material Index 43 Identification of Candidate Material Classes 5 Detailed Comparison of Candidate Materials 51 The Shortlisted Candidates 511 Alumina Al₂O₃ 512 Polyether ether ketone PEEK 513 GlassFibre Reinforced Polymer GFRP 52 Quantitative Comparison using a Merit Rating Chart 53 Qualitative Discussion of Candidates 531 Alumina Performance vs Practicality 532 PEEK The HighPerformance Polymer 533 GFRP The Balanced Composite 54 Selection Rationale 6 Final Material Choice GlassFibre Reinforced Polymer GFRP 61 Justification of Final Selection 62 Potential Manufacturing Considerations 7 Sustainability Analysis 71 Sustainability of the Design Choice Performance and Longevity 72 Resource Management 73 Environmental Impact of Manufacturing 74 EndofLife EoL Plan 8 Conclusion 9 References 1 1 Introduction 11 The Electromagnetic Relay Function and Significance An electromagnetic relay is a fundamental component in electrical engineering serving as a switch that is operated by an electrical current It is imperative to accurately evaluate their reliability so that operation and maintenance activities can be appropriately planned to guarantee the safe and stable operation of the system Xiang et al 2023 p1 Its core principle involves using a small control current flowing through a coil to generate a magnetic field which in turn actuates a mechanical armature to open or close a separate often higherpower electrical circuit This electrical isolation between the control and load circuits is a key advantage allowing lowpower logic systems like microcontrollers to safely control highvoltage or highcurrent devices such as motors lights and heaters Relays are ubiquitous found in everything from automotive control units and industrial automation systems to telecommunications and home appliances In fact the industrial appliances such as machinery motors fans lights and air conditioners can be monitored and controlled using Industrial Automation Magesh et al 2022 p1 12 The Role of the Relay Arm The relay arm technically known as the armature is the mechanical heart of the relay It is a movable lever typically pivoted at one end When the electromagnet is de energized a spring holds the armature in a default position keeping a set of electrical contacts either open or closed When the coil is energized the resulting magnetic force overcomes the spring force and pulls the armature towards the coils core This movement causes the electrical contacts at the end of the armature to change state eg from open to closed thereby completing the secondary circuit Pullin voltage and release voltage are important parameters to ensure the reliable operation of the relay then the aerospace field has further put forward higher requirements which are to reduce the pullin voltage and increase the release voltage of the relay Liu et al 2023 p1 The performance of the entire relay is critically dependent on the characteristics of this arm Its speed of movement dictates the relays response time the delay between energizing the coil and the contacts switching Its durability determines the relays 2 operational lifespan which is often measured in millions of cycles Therefore the material chosen for the relay arm is not a trivial decision it is a key design parameter that directly impacts the devices speed reliability and longevity 13 The Ashby Materials Selection Methodology To address this complex design challenge this report will employ the systematic materials selection methodology developed by Professor Michael Ashby Ashby 2011 This approach transforms the oftenvague design requirements into a clear logical and defensible process The methodology consists of four key steps 1 Translation Deconstructing the design requirements into a precise statement of function objectives constraints and free variables 2 Screening Eliminating materials that cannot meet the absolute performance constraints the gonogo criteria 3 Ranking Deriving a material indexa combination of material properties that maximizes the designs objectiveand using it to rank the surviving materials 4 Documentation Researching the topranked candidates in greater detail to make a final welldocumented and justified choice often considering factors like cost manufacturability and environmental impact Ashby 2011 This structured process prevents premature selection of familiar materials and opens the door to innovative solutions by exploring the entire universe of materials in an unbiased manner 14 Report Objectives and Structure The primary objective of this report is to conduct a complete materials selection process for a highperformance relay arm following the task requirements The specific design goal is to select a material that minimizes the response time while ensuring the arm does not fail in fatigue over its intended service life The report is structured to follow the Ashby method logically 3 Section 2 will translate the design problem defining the loading case objectives and constraints in detail Section 3 will provide a complete stepbystep derivation of the material index required to optimize the objective Section 4 will use Ashby property charts to screen out unsuitable materials and then rank the remaining candidates using the derived index Section 5 will conduct a detailed comparison of the leading materials Section 6 will declare the final material choice and provide a robust justification Section 7 will analyze the sustainability and environmental implications of the chosen material Section 8 will conclude the report with a summary of the findings 2 Design Requirements Initial Criteria This section breaks down the design problem into the formal structure required by the Ashby methodology This process ensures all requirements are explicitly stated and justified 21 Function Objective Constraints and Free Variables Function The component is a relay arm armature for an electromagnetic switch Its function is to pivot under an applied magnetic force to actuate a set of electrical contacts Objective The primary performance goal is to minimize the response time of the switch A faster response time allows the relay to operate at higher frequencies and with greater precision Constraints Nonnegotiable conditions 1 Fatigue Resistance The arm is subjected to millions of onoff cycles The materials fatigue strength endurance limit σe must be greater than the maximum operating stress σmax Constraint Must not fail in fatigue 2 Sufficient Stiffness The arm must be stiff enough to move as a rigid body and actuate the contacts without excessive bending A maximum allowable deflection δmax under the magnetic load F is specified Constraint Deflection δ δmax 4 3 Electrical Insulation The armature itself must be an electrical insulator to prevent the control circuits current from shorting to the load circuits contacts Constraint High electrical resistivity 4 Geometric Constraints The overall length L of the arm is specified and fixed by the relays housing and coil design 5 Operational Temperature The material must maintain its properties within a typical operating temperature range for electronic components for instance 20C to 85C Kirpik et al 2023 Free Variables 1 Material Choice This is the primary free variable we seek to determine 2 CrossSectional Shape and Area A While the length L is fixed the crosssectional geometry eg width b and height h of a rectangular section can be varied to meet the stiffness and strength constraints This is an important free variable in the derivation 22 The Loading Case and Geometric Model To analyze the component we must model its geometry and loading Geometric Model The relay arm is best approximated as a cantilever beam Vidyadhara et al 2022 It is fixed at the pivot point and free at the end where the magnetic force is applied and the contacts are located For derivation we will assume a simple rectangular crosssection of width b and height h This is a common and effective shape for such components Loading Case The arm is subjected to a cyclic point load F applied at its free end at length L from the pivot This force is the magnetic attraction from the energized coil When the coil is deenergized the force is removed and a return spring or the inherent stiffness of the contacts pushes the arm back This creates a fully reversed or repeated stress cycle making fatigue a primary failure mode The loading is dynamic not static 5 23 Key Assumptions and Justifications To make the problem tractable several welldefended assumptions are necessary 1 Response Time and Natural Frequency We assume that minimizing response time is equivalent to maximizing the fundamental natural frequency ω of the arm A component with a higher natural frequency can oscillate and settle more quickly leading to a faster actuation Nayfeh and Mook 2024 This is a standard approach in the design of highspeed mechanical systems as it prevents resonance with any driving frequencies and allows for rapid state changes 2 Dominant Failure Mode is Fatigue We assume that for a properly designed arm ie one that meets the stiffness constraint the primary mode of failure over its lifetime will be highcycle fatigue due to the millions of actuation cycles AVATEFFAZELI et al 2022 We will neglect other failure modes like creep as the operating temperatures are moderate and the static loads are low 3 Simplified Loading We model the magnetic force as a point load F at the end of the beam The force may be distributed but the point load model provides the maximum bending moment and stress at the cantilever root Zhang and Fu 2023 representing a conservative worstcase scenario for design 4 Isotropic Material Properties During the initial derivation and screening we will assume the materials are isotropic properties are the same in all directions This is valid for unfilled polymers and ceramics For composites like GFRP which are anisotropic this assumption will be revisited during the detailed comparison stage where the orientation of fibers becomes a critical design parameter Zhao et al 2024 5 Small Deflections We assume the arm operates within the regime of small deflection theory where linear elastic behavior holds This is a valid assumption as large deflections would imply a poorly designed overly flexible arm that would fail to actuate the contacts reliably 6 24 Summary of Design Requirements Component Relay Arm Armature Function Pivot to actuate electrical contacts Objective Minimize response time equivalent to Maximize natural frequency ω Constraints 1 Fatigue strength σe operating stress σmax 2 Deflection δ δmax 3 High electrical resistivity 4 Fixed length L 5 Operation from 20C to 85C Free Variables 1 Material choice 2 Crosssectional area A and shape 3 Derivation of the Material Index The goal of this section is to derive a performance indexa group of material properties that must be maximized to achieve our design objective 31 Translating the Design Objective into a Performance Equation As established our objective is to maximize the fundamental first mode natural frequency ω of the relay arm For a cantilever beam the natural frequency is given by the standard formula Yuan Zhuang and Xu 2024 ω C₁ K meff Where ω is the fundamental natural frequency in rads K is the stiffness of the beam at the point of interest K Fδ meff is the effective mass of the beam 7 C₁ is a constant that depends on the boundary conditions for a cantilever beam it incorporates factors from the mode shape A more direct form for the fundamental frequency of a cantilever beam of length L is ω β₁² EI ρAL⁴ 1 Where β₁² is a constant for the fundamental mode of a cantilever beam β₁ 1875 so β₁² 352 Ahiwale et al 2022 E is the Youngs Modulus of the material a material property I is the second moment of area of the beams crosssection a geometric property ρ is the density of the material a material property A is the crosssectional area a geometric property L is the length of the beam a fixed functional requirement Our goal is to maximize ω 32 Formulating the Objective Function From Equation 1 we can see that our objective is to maximize the term EI ρAL⁴ Lets analyze the components Material Properties E Youngs Modulus ρ Density Geometric Properties I Second moment of area A Crosssectional area Functional Requirement L Length which is fixed The geometry I and A is a free variable We can make the arm thicker or thinner However we cannot simply make it infinitely thick as this would increase mass and likely violate other constraints The key insight of the Ashby method is to use a constraint to eliminate the free geometric variable 8 Lets assume a rectangular crosssection of width b and height h Area A b h Second moment of area I b h³ 12 Substituting these into Equation 1 ω β₁² E bh³12 ρ bh L⁴ Now we simplify the terms inside the square root ω β₁² E h² 12 ρ L⁴ Pulling the geometric and fixed terms out of the square root ω β₁² h 12 L² E ρ 2 33 Isolating Material Geometry and Functional Parameters Equation 2 neatly separates the different aspects of the design ω Functional Part Geometric Part Material Part Functional Part β₁² 12 L² This part is determined by the components function a cantilever beam of fixed length L It is constant for this problem Geometric Part h This is the height of the beam our free geometric variable Material Part E ρ This combination of material properties is what we need to maximize At this point we have a choice We could simply declare that the material index is E ρ However the geometry term h is still free A robust derivation links this free variable to a constraint While the stiffness constraint δ δmax could be used in this case the design is geometry limited This means we can select any geometry value of h we want if it meets the stiffness and strength constraints The objective function 9 Equation 2 shows that for any chosen material increasing h will always increase the natural frequency Therefore the task simplifies to get the highest possible natural frequency we should choose the material that provides the highest value of E ρ Maximizing E ρ is mathematically identical to maximizing the simpler index M E ρ This index is known as the specific stiffness or specific modulus of a material 34 The Final Material Performance Index The material index to be maximized to achieve the objective of minimum response time for a relay arm of a given length and free crosssection is M₁ E ρ This index tells us to search for materials that are simultaneously very stiff high E and very light low ρ These materials will vibrate at the highest possible frequency for a given geometry thus providing the fastest possible response time The other constraints fatigue strength electrical resistivity will be used as screening filters to narrow the field of potential materials before we apply this index 4 Material Screening and DownSelection using Ashby Charts With the material index M₁ Eρ derived we can now use Ashby property charts to systematically search for the best materials This process is divided into two stages screening and ranking optimization We will use the Youngs Modulus vs Density Ashby chart as both properties are present in our index 10 41 Stage 1 Screening with Hard Constraints Before we look for the material with the highest Eρ we must first eliminate all materials that fail to meet our nonnegotiable constraints The relay arm must be an electrical insulator and this is a critical safety and functional requirement We need to set a limit on electrical resistivity considering a good insulator has a resistivity greater than 10¹⁰ Ωm Mitolo 2025 pp 38 Action On the Ashby chart this constraint immediately eliminates the entire class of Metals and Alloys They are conductors This is a massive reduction in the search space We are left with Polymers Ceramics Composites and some natural materials The arm must not fail in fatigue This requires the materials fatigue strength or endurance limit σe to be greater than the maximum bending stress experienced in service σmax While σmax depends on the final geometry and applied force we can set a reasonable minimum requirement for a small electromechanical component A conservative minimum fatigue strength of σe 30 MPa is a suitable starting point This value is high enough to ensure durability but not so high as to exclude viable polymers Olugbade et al 2021 Action We apply this limit on a Strength vs Density chart or by consulting property data for the material classes that survived the first screen Many commodity polymers like PE PP and elastomers will be eliminated as their fatigue strengths are too low Engineering polymers Nylon PC PEEK technical ceramics Alumina Silicon Nitride and composites GFRP CFRP generally meet this requirement Chavez et al 2022 The material must function from 20C to 85C This constraint eliminates materials that become brittle at low temperatures or soften at high temperatures Most engineering polymers ceramics and composites are suitable within this range It does however screen out some lowgrade polymers and waxes Akman and Sadhu 2024 11 42 Stage 2 Optimization using the Material Index After screening we are left with candidate materials primarily from the Polymer Ceramic and Composite families We now apply our derived material index M₁ Eρ to rank these survivors On a loglog plot of Youngs Modulus E vs Density ρ the index M₁ can be represented as a selection line Taking the logarithm of our index equation M₁ Eρ logM₁ logEρ logM₁ logE logρ logE logρ logM₁ This is the equation of a straight line on the loglog chart with a slope of 1 To maximize M₁ we need to maximize the yintercept logM₁ This is achieved by drawing a line with a slope of 1 and moving it as far as possible to the topleft of the chart as this region represents high E and low ρ Yamaguchi and Yang 2022 The image below shows a representative E vs ρ Ashby chart with the screening and ranking steps illustrated Figure 1 Ashby Chart Source Wikimedia Commons 2025 12 43 Identification of Candidate Material Classes By moving the selection line to the topleft we can identify the material families that offer the best performance for our objective 1 Engineering Ceramics Materials like Alumina Al₂O₃ Silicon Carbide SiC and Silicon Nitride Si₃N₄ are located very high on the chart and far to the left They offer exceptionally high Eρ values 2 Composites CarbonFibre Reinforced Polymers CFRP and GlassFibre Reinforced Polymers GFRP also occupy a prime position in the topleft Their combination of a light polymer matrix with stiff reinforcing fibers gives them excellent specific stiffness often on par with or exceeding that of metals 3 HighPerformance Engineering Polymers Some advanced polymers like Polyether ether ketone PEEK and certain Polyamides Nylons while not as high as ceramics or composites still offer a good balance of properties and lie in the upper region of the polymer family Based on this analysis we will select one representative material from each of these three promising classes for a more detailed comparison 5 Detailed Comparison of Candidate Materials The Ashby chart analysis has successfully narrowed the vast universe of materials down to three promising classes We now select a representative candidate from each class for a rigorous headtohead comparison to make the final selection 51 The Shortlisted Candidates 1 Alumina Aluminum Oxide Al₂O₃ A leading representative of the Engineering Ceramics class It is widely available relatively lowcost for a ceramic and known for its hardness and high modulus Boldin et al 2021 2 Polyether ether ketone PEEK A highperformance semicrystalline thermoplastic representing the best of the Engineering Polymers It is renowned 13 for its excellent mechanical properties thermal stability and chemical resistance Zol et al 2023 3 GlassFibre Reinforced Polymer GFRP A prime example of the Composites class Specifically we will consider a standard epoxy matrix with Eglass fibers It is chosen over CFRP for its lower cost and better electrical insulation properties carbon fibers can be slightly conductive Zhang et al 2023 52 Quantitative Comparison using a Merit Rating Chart To compare these materials objectively we will use a table of key properties The properties include our primary index Eρ our constraint properties fatigue strength resistivity and other important practical considerations like fracture toughness cost and manufacturability Property Alumina Al₂O₃ PEEK Unfilled GFRP Epoxy 60 E Glass Units Importance to Design Performance Properties Youngs Modulus E 380 38 45 longitudinal GPa High is better Stiffness Density ρ 3800 1300 1900 kgm ³ Low is better Lightweight Material Index M₁ Eρ 100 29 237 GPa kgm ³ x10³ Maximize Primary Objective Constraint Secondary Properties Fatigue Strength σe 10⁷ cycles 150 80 250 tensiontension MPa Must be σoperating eg 30 MPa Electrical Resistivity 10¹⁴ 10¹⁴ 10¹⁴ Ωm Must be high Insulator Fracture Toughness KIc 2 4 25 35 25 35 MPam¹² High is better Resists Cracks 14 Max Service Temp 1000 240 150 C Must be 85C Practical Considerations Relative Cost Raw Material Medium Very High LowMedium Low is better Manufacturability for small complex part Difficult sintering grinding Excellent injection molding Good compressioninjection molding Ease of processing reduces final cost Granta Design 2020 53 Qualitative Discussion of Candidates The quantitative data tells only part of the story A qualitative analysis is essential to understand the practical tradeoffs On paper Alumina is the clear winner based purely on the material index M₁ 100 Its extremely high modulus combined with a moderate density gives it unparalleled specific stiffness It also has excellent fatigue and temperature resistance However its Achilles heel is its catastrophically low fracture toughness KIc Alumina is a classic brittle ceramic This means it has virtually no ability to tolerate microscopic flaws In a dynamic application with millions of stress cycles and potential for minor impacts during assembly or operation a tiny crack could propagate almost instantaneously leading to complete failure without warning Furthermore manufacturing small precise Alumina parts is difficult and expensive typically requiring powder pressing hightemperature sintering and diamond grinding to achieve final dimensions Kishore et al 2022 Verdict Too brittle and difficult to manufacture for this application The risk of sudden failure is too high PEEK is an impressive material While its Eρ index is the lowest of the three it is still very good for a polymer Its key advantages are its excellent fatigue strength and its relative toughness which is comparable to Alumina but in a material that yields before breaking Its greatest strength is manufacturability PEEK can be precision injection molded into complex net shapes drastically reducing manufacturing costs for highvolume production compared to machining ceramics citation 27 15 However its raw material cost is very high often making it prohibitive unless its specific combination of properties like extreme chemical resistance or hightemperature performance which we dont fully need here is essential Verdict A very strong but potentially overengineered and expensive candidate GFRP strikes an exceptional balance Its specific stiffness M₁ 24 is an order of magnitude better than PEEK and is competitive with many metals though not as high as Alumina Its standout feature is its combination of properties Excellent Fatigue Strength Composites are known for their superb performance under cyclic loading often outperforming metals High Fracture Toughness The composite structure with fibers embedded in a polymer matrix provides multiple mechanisms for arresting crack growth The toughness of GFRP is an order of magnitude higher than that of Alumina making it far more reliable and damagetolerant Good Manufacturability GFRP components can be produced efficiently using methods like compression molding or injection molding for shortfiber variants allowing for complex shapes Low Cost Glass fiber and common polymer resins like epoxy or polyester are relatively inexpensive materials making GFRP a very costeffective solution The main complication is its anisotropy its properties are best along the direction of the fibers However this can be used as a design advantage By aligning the long glass fibers along the length of the relay arm the direction of maximum bending stress we can maximize performance precisely where it is needed This extreme brittleness is particularly dangerous in a highcycle fatigue application where any microscopic manufacturing flaw or surface scratch can act as a stress concentrator leading to rapid crack initiation and catastrophic failure with little or no warning 54 Selection Rationale Comparing the three candidates 16 Alumina is rejected due to its brittleness low fracture toughness which poses an unacceptable risk of catastrophic failure in a dynamic component PEEK is a viable but very expensive option Its performance does not justify the significant cost increase over GFRP for this specific application GFRP emerges as the optimal choice It offers a superior combination of high specific stiffness outstanding fatigue resistance excellent fracture toughness damage tolerance low cost and good manufacturability 6 Final Material Choice GlassFibre Reinforced Polymer GFRP 61 Justification of Final Selection Based on the comprehensive analysis performed in the preceding sections the final material selected for the electromagnetic switch relay arm is GlassFibre Reinforced Polymer GFRP specifically a composition of continuous Eglass fibers aligned longitudinally within an epoxy resin matrix This choice is justified by the following key points which directly address the design objectives and constraints 1 Optimized Objective Response Time GFRP possesses a very high specific stiffness Eρ second only to highperformance ceramics This ensures a high natural frequency leading to a fast response time directly meeting the primary design objective 2 Fatigue Resistance GFRP exhibits excellent resistance to fatigue failure a critical requirement for a component cycled millions of times Its fatigue endurance limit is superior to most engineering polymers and many metals guaranteeing a long and reliable service life 3 Damage Tolerance Toughness This is the deciding factor over ceramics GFRPs high fracture toughness means it can withstand minor impacts and resist the propagation of microcracks preventing the sudden catastrophic failure characteristic of brittle materials like Alumina This ensures the relay fails safely or not at all 17 4 Constraint Compliance GFRP is an excellent electrical insulator easily meeting the resistivity requirement It also maintains its mechanical properties well within the specified service temperature range 5 CostEffectiveness Compared to both PEEK and machined Alumina GFRP offers a significantly lower cost for the high level of performance it delivers making it an economically sound choice for mass production 6 Design Flexibility The anisotropic nature of GFRP allows for tailored design where fiber orientation can be optimized to align with the principal stress directions along the length of the cantilevered arm maximizing stiffness and strength exactly where needed 62 Potential Manufacturing Considerations The chosen manufacturing process would likely be pultrusion to create stock rods with continuous aligned fibers followed by a cutting and shaping process Alternatively for more complex arm geometries compression molding of a preimpregnated composite sheet prepreg would be ideal This process uses heat and pressure to cure the part into its final net shape ensuring high fiber volume fraction and minimal voids leading to optimal mechanical properties Quality control would be essential to ensure proper fiber alignment and full curing of the resin 7 Sustainability Analysis A responsible engineering choice goes beyond just technical performance and cost it must also consider the environmental and societal impact of the material throughout its life cycle 71 Sustainability of the Design Choice Performance and Longevity At first glance a polymer composite derived from fossil fuels does not seem like a sustainable choice However sustainability can be viewed through the lens of the products entire life cycle The justification for selecting GFRP is based on inuse performance and longevity A highly efficient fast and reliable relay contributes to the energy efficiency 18 of the larger system it controls More importantly its exceptional fatigue resistance and durability mean the component will not need to be replaced for a very long time A product that lasts significantly longer reduces the total material and energy consumption associated with manufacturing and distributing replacements over the lifetime of the host device Therefore choosing a highperformance material like GFRP which extends the products life is a form of sustainable design 72 Resource Management We must analyze where the constituent materials for GFRP come from Glass Fibers The primary raw material for Eglass fibers is silica sand which is one of the most abundant minerals on Earth Other components include limestone and soda ash which are also widely available The extraction of these minerals involves quarrying which has a local environmental impact but does not face resource scarcity issues Epoxy Resin The polymer matrix is the more problematic component Epoxy resins are thermosetting polymers derived from feedstocks like epichlorohydrin and bisphenolA which are produced from crude oil This makes the matrix dependent on a nonrenewable fossilfuel resource This is the primary sustainability drawback of the material Research into biobased epoxy resins is ongoing but they are not yet as commercially mature or highperformance 73 Environmental Impact of Manufacturing The production of GFRP has several environmental considerations Embodied Energy The manufacturing process involves melting sand to create glass fibers and synthesizing the polymer resin both of which are energy intensive However the embodied energy of GFRP is generally lower than that of primary aluminum and significantly lower than that of engineering ceramics like Alumina which require extremely hightemperature sintering often 1600C Emissions The synthesis of epoxy resins can involve hazardous chemicals During the curing process of the composite volatile organic compounds VOCs 19 can be released although modern manufacturing facilities use closed systems and scrubbers to minimize these emissions 74 EndofLife EoL Plan The endoflife phase is the most significant challenge for thermoset composites like GFRP Because the polymer matrix is crosslinked it cannot be simply melted and remolded like a thermoplastic 1 Current Status The vast majority of GFRP waste currently goes to landfill This is not a sustainable solution 2 Recycling Options Several EoL technologies are emerging though they face economic and logistical hurdles citation 35 o Mechanical Recycling The composite is ground into a powder or short fibers This material can be used as a filler or reinforcement in other products eg concrete asphalt or lowergrade plastics This is technically downcycling as the high mechanical properties of the original aligned fibers are lost o Thermal Recycling Pyrolysis The composite is heated in an oxygen free environment This breaks down the polymer matrix into oils and gases that can be used as fuel energy recovery and it recovers the glass fibers The recovered fibers retain much of their strength and can be repurposed into new composites o Chemical Recycling Solvolysis This process uses solvents at high temperatures and pressures to chemically dissolve the polymer matrix allowing for the recovery of both the glass fibers and the chemical constituents of the resin This is a promising but currently expensive and less mature technology Proposed EoL Plan for the Relay Arm Design for Disassembly The relay should be designed so the arm can be easily separated from the metallic components 20 Material Labeling The arm should be labeled with the standard composite material code to facilitate sorting Producer Responsibility A takeback program could be established where the manufacturer partners with a specialized composite recycling facility that employs pyrolysis or solvolysis to recover value from the endoflife components 8 Conclusion This report has successfully executed a comprehensive materials selection process for a highperformance electromagnetic relay arm using the Ashby methodology The primary design objective of minimizing response time coupled with critical constraints of fatigue life stiffness and electrical insulation led to the derivation of a material performance index of M₁ Eρ Through a systematic process of screening and ranking using Ashby charts three classes of materials engineering ceramics highperformance polymers and composites were identified as top performers A detailed comparison of representative candidates Alumina PEEK and GFRP weighed their technical merits against practical considerations of fracture toughness manufacturability and cost While Alumina offered the highest theoretical performance it was rejected due to its inherent brittleness which poses an unacceptable risk of catastrophic failure PEEK was found to be a capable but overly expensive solution GlassFibre Reinforced Polymer GFRP was ultimately selected as the optimal material It provides an outstanding and balanced profile of high specific stiffness exceptional fatigue strength superior damage tolerance low cost and proven manufacturability The sustainability of GFRP was also considered While its reliance on fossilfuel based resins and endoflife challenges are notable drawbacks its selection is justified by the enhanced performance energy efficiency and extended service life it provides to the final product A forwardlooking endoflife plan involving emerging recycling technologies was proposed to mitigate its environmental impact In conclusion GFRP represents the most robust reliable and wellrounded engineering solution for this demanding application 21 9 References Ahiwale D Ingole S Raut M Rathod A and Gedam R 2022 Modal analysis of cracked cantilever beam using ANSYS software Materials Today Proceedings 56 pp 165170 doi 101016jmatpr202112181 Akman A and Sadhu A 2024 Recent development of 3Dprinting technology in construction engineering Practice Periodical on Structural Design and Construction 291 03123005 doi 101061PPSCFXSCENG1405 Ashby MF 2011 Materials Selection in Mechanical Design 4th edn Oxford ButterworthHeinemann Avateffazeli M Zuo G Zhao Y Zhang Y and Huang HZ 2022 Very high cycle fatigue at elevated temperatures a review on high temperature ultrasonic fatigue Journal of Space Safety Engineering 94 pp 488512 doi 101016jjsse202209006 Boldin MS Shishkin AV Firsov EV Shishkin AA Smirnov IV Golikov DA and Fedorov AV 2021 Review of ballistic performance of alumina comparison of alumina with silicon carbide and boron carbide Ceramics International 4718 pp 2520125213 doi 101016jceramint202105283 Chavez LA Ibave P Hassan MS HallSanchez SE Billah KMM Leyva A Marquez C Espalin D Torres S Robison T and Lin Y 2022 Lowtemperature selective laser sintering 3D printing of PEEKNylon blends impact of thermal post processing on mechanical properties and thermal stability Journal of Applied Polymer Science 13923 52290 doi 101002app52290 Granta Design 2020 CES EduPack Software Computer program Cambridge Granta Design Kirpik MG Demir H Yanardağ E and Keskin MG 2023 Application of Ashby method for optimization of high strength low priced bucket for silo elevators Osmaniye Korkut Ata Üniversitesi Fen Bilimleri Enstitüsü Dergisi 63 pp 22132233 doi 1047495okufbed1235492 Kishore K Sinha MK Rajesh S Singh A and Korkmaz ME 2022 A comprehensive review on the grinding process advancements applications and 22 challenges Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science 23622 pp 1092310952 doi 10117709544062221110782 Liu G Li Z Zhang K Xu Y and Li J 2022 A new electromagnetic structure of relay with composite armature containing permanent magnet in Annual Conference of China Electrotechnical Society Springer Nature Singapore Singapore pp 370376 Magesh PR Sankari HP Lokeshwaran H and Ezhilarasan K 2022 IoT based industrial automation for various load using ATmega328p microcontroller 2022 6th International Conference on Intelligent Computing and Control Systems ICICCS pp 471475 doi 101109ICICCS5371820229788258 Mitolo M 2024 Principles and Practices of Electrical Safety Engineering Ensuring Protection in Electrical Systems Boca Raton CRC Press Nayfeh AH and Mook DT 2024 Nonlinear Oscillations New York John Wiley Sons Olugbade TO Akpan EI Afolalu SA Fayomi OSI and Okeniyi JO 2021 A review on the corrosion fatigue strength of surfacemodified stainless steels Journal of the Brazilian Society of Mechanical Sciences and Engineering 439 421 doi 101007s40430021031405 Pimenta S and Pinho ST 2011 Recycling of thermoset composites Composites Part A Applied Science and Manufacturing 426 pp 579593 doi 101016jcompositesa201101018 Vidyadhara BV Praveen TA Murthy MK and Ghose D 2022 Design and integration of a drone based passive manipulator for capturing flying targets Robotica 407 pp 23492364 doi 101017S026357472100234X Xiang S Zhao C Hao S Li K and Li W 2023 A reliability evaluation method for electromagnetic relays based on a novel degradationthresholdshock model with two sided failure thresholds Reliability Engineering System Safety 240 109549 doi101016jress2023109549 Yamaguchi K and Yang J 2022 Analysis of origamibased mechanical metamaterials via extended three dimensional Ashby chart Active and Passive Smart Structures and Integrated Systems XVI 12043 1204313 doi 101117122612745 23 Yuan M Zhuang J and Xu Z 2024 Modeling and analysis of coupled dynamics of relay considering collision bouncing in 2024 3rd Asia Power and Electrical Technology Conference APET IEEE Chengdu pp 3640 doi 101109APET61379202410526012 Zhang X and Fu X 2023 New theoretical models for the bending moment of thin walled beams under threepoint bending Applied Mathematical Modelling 121 pp 21 42 doi 101016japm202303024 Zhang M Li X Huang X Li M Li D and Qian C 2023 Improving dispersion of recycled GFRP fiber in cement mortar with sodium hexametaphosphate Cement and Concrete Composites 143 105232 doi 101016jcemconcomp2023105232 Zhao T Zhang J Shen Q Huang Y and Lei B 2024 Experimental research and theoretical prediction on mechanical properties for recycled GFRP fiber reinforced concrete Journal of Building Engineering 91 109643 doi 101016jjobe2024109643 Zol SM Tsoi JKH Zhang S Chow TW Cheung JYN and Mat NNN 2023 Description of poly aryletherketone materials PAEKs polyetheretherketone PEEK and polyetherketoneketone PEKK for application as a dental material a materials science review Polymers 159 2170 doi 103390polym15092170 Materials Selection for an Electromagnetic Switch Relay Arm A Report on the Application of the Ashby Methodology for Optimized Performance and Fatigue Resistance Your Name Your Student ID Course NameCode Date Executive Summary This report details a systematic materials selection process for a critical component the armature or relay arm of an electromagnetic switch The primary design objective is to minimize the response time of the switch which directly translates to maximizing the operational speed of the relay This objective is subject to the critical constraints that the arm must not fail under cyclic fatigue loading must possess sufficient stiffness to actuate correctly and must function as an electrical insulator The Ashby methodology of materials selection was employed to provide a structured quantitative and transparent approach The relay arm was modelled as a cantilever beam subject to a dynamic point load The objective of minimizing response time was translated into maximizing the arms fundamental natural frequency of vibration Through a rigorous derivation the primary material index for this objective was identified as M Eρ where E is the Youngs Modulus and ρ is the density This index seeks materials that are both stiff and lightweight Additional screening criteria were established including a minimum fatigue strength high electrical resistivity and adequate fracture toughness to prevent catastrophic failure An initial screening process using Ashby charts eliminated metals due to electrical conductivity and many polymers due to low stiffness The optimization process using the derived material index highlighted engineering ceramics high performance polymers and fiberreinforced composites as leading candidate classes Three specific materials were downselected for detailed comparison Alumina Al O Polyether ether ketone PEEK and GlassFibre Reinforced Polymer GFRP ₂ ₃ A weighted property index and qualitative analysis revealed that while Alumina offers the highest theoretical performance index its extreme brittleness low fracture toughness and difficult manufacturability present unacceptable risks for a dynamic component GlassFibre Reinforced Polymer GFRP was selected as the final material choice It provides an outstanding balance of high specific stiffness Eρ excellent fatigue resistance low cost high toughness and manufacturability via molding processes A comprehensive sustainability analysis was also conducted While GFRP is a fossil fuelderived material with endoflife challenges its selection is justified by the operational energy savings of a highperformance longlasting relay and its favorable embodied energy compared to alternatives like ceramics A plan for endoflife management focusing on emerging recycling technologies is also proposed This report concludes that GFRP represents the most robust and wellrounded engineering solution for this demanding application Table of Contents 1 Introduction 11 The Electromagnetic Relay Function and Significance 12 The Role of the Relay Arm 13 The Ashby Materials Selection Methodology 14 Report Objectives and Structure 2 Design Requirements Initial Criteria 21 Function Objective Constraints and Free Variables 22 The Loading Case and Geometric Model 23 Key Assumptions and Justifications 24 Summary of Design Requirements 3 Derivation of the Material Index 31 Translating the Design Objective into a Performance Equation 32 Formulating the Objective Function 33 Isolating Material Geometry and Functional Parameters 34 The Final Material Performance Index 4 Material Screening and DownSelection using Ashby Charts 41 Stage 1 Screening with Hard Constraints 411 Electrical Resistivity 412 Fatigue Strength 413 Service Temperature 42 Stage 2 Optimization using the Material Index 43 Identification of Candidate Material Classes 5 Detailed Comparison of Candidate Materials 51 The Shortlisted Candidates 511 Alumina Al O ₂ ₃ 512 Polyether ether ketone PEEK 513 GlassFibre Reinforced Polymer GFRP 52 Quantitative Comparison using a Merit Rating Chart 53 Qualitative Discussion of Candidates 531 Alumina Performance vs Practicality 532 PEEK The HighPerformance Polymer 533 GFRP The Balanced Composite 54 Selection Rationale 6 Final Material Choice GlassFibre Reinforced Polymer GFRP 61 Justification of Final Selection 62 Potential Manufacturing Considerations 7 Sustainability Analysis 71 Sustainability of the Design Choice Performance and Longevity 72 Resource Management 73 Environmental Impact of Manufacturing 74 EndofLife EoL Plan 8 Conclusion 9 References 1 1 Introduction 11 The Electromagnetic Relay Function and Significance An electromagnetic relay is a fundamental component in electrical engineering serving as a switch that is operated by an electrical current It is imperative to accurately evaluate their reliability so that operation and maintenance activities can be appropriately planned to guarantee the safe and stable operation of the system Xiang et al 2023 p1 Its core principle involves using a small control current flowing through a coil to generate a magnetic field which in turn actuates a mechanical armature to open or close a separate often higherpower electrical circuit This electrical isolation between the control and load circuits is a key advantage allowing lowpower logic systems like microcontrollers to safely control highvoltage or highcurrent devices such as motors lights and heaters Relays are ubiquitous found in everything from automotive control units and industrial automation systems to telecommunications and home appliances In fact the industrial appliances such as machinery motors fans lights and air conditioners can be monitored and controlled using Industrial Automation Magesh et al 2022 p1 12 The Role of the Relay Arm The relay arm technically known as the armature is the mechanical heart of the relay It is a movable lever typically pivoted at one end When the electromagnet is deenergized a spring holds the armature in a default position keeping a set of electrical contacts either open or closed When the coil is energized the resulting magnetic force overcomes the spring force and pulls the armature towards the coils core This movement causes the electrical contacts at the end of the armature to change state eg from open to closed thereby completing the secondary circuit Pullin voltage and release voltage are important parameters to ensure the reliable operation of the relay then the aerospace field has further put forward higher requirements which are to reduce the pullin voltage and increase the release voltage of the relay Liu et al 2023 p1 2 The performance of the entire relay is critically dependent on the characteristics of this arm Its speed of movement dictates the relays response time the delay between energizing the coil and the contacts switching Its durability determines the relays operational lifespan which is often measured in millions of cycles Therefore the material chosen for the relay arm is not a trivial decision it is a key design parameter that directly impacts the devices speed reliability and longevity 13 The Ashby Materials Selection Methodology To address this complex design challenge this report will employ the systematic materials selection methodology developed by Professor Michael Ashby Ashby 2011 This approach transforms the oftenvague design requirements into a clear logical and defensible process The methodology consists of four key steps 1 Translation Deconstructing the design requirements into a precise statement of function objectives constraints and free variables 2 Screening Eliminating materials that cannot meet the absolute performance constraints the gonogo criteria 3 Ranking Deriving a material indexa combination of material properties that maximizes the designs objectiveand using it to rank the surviving materials 4 Documentation Researching the topranked candidates in greater detail to make a final welldocumented and justified choice often considering factors like cost manufacturability and environmental impact Ashby 2011 This structured process prevents premature selection of familiar materials and opens the door to innovative solutions by exploring the entire universe of materials in an unbiased manner 14 Report Objectives and Structure The primary objective of this report is to conduct a complete materials selection process for a highperformance relay arm following the task requirements The specific 3 design goal is to select a material that minimizes the response time while ensuring the arm does not fail in fatigue over its intended service life The report is structured to follow the Ashby method logically Section 2 will translate the design problem defining the loading case objectives and constraints in detail Section 3 will provide a complete stepbystep derivation of the material index required to optimize the objective Section 4 will use Ashby property charts to screen out unsuitable materials and then rank the remaining candidates using the derived index Section 5 will conduct a detailed comparison of the leading materials Section 6 will declare the final material choice and provide a robust justification Section 7 will analyze the sustainability and environmental implications of the chosen material Section 8 will conclude the report with a summary of the findings 2 Design Requirements Initial Criteria This section breaks down the design problem into the formal structure required by the Ashby methodology This process ensures all requirements are explicitly stated and justified 21 Function Objective Constraints and Free Variables Function The component is a relay arm armature for an electromagnetic switch Its function is to pivot under an applied magnetic force to actuate a set of electrical contacts Objective The primary performance goal is to minimize the response time of the switch A faster response time allows the relay to operate at higher frequencies and with greater precision Constraints Nonnegotiable conditions 4 1 Fatigue Resistance The arm is subjected to millions of onoff cycles The materials fatigue strength endurance limit σe must be greater than the maximum operating stress σmax Constraint Must not fail in fatigue 2 Sufficient Stiffness The arm must be stiff enough to move as a rigid body and actuate the contacts without excessive bending A maximum allowable deflection δmax under the magnetic load F is specified Constraint Deflection δ δmax 3 Electrical Insulation The armature itself must be an electrical insulator to prevent the control circuits current from shorting to the load circuits contacts Constraint High electrical resistivity 4 Geometric Constraints The overall length L of the arm is specified and fixed by the relays housing and coil design 5 Operational Temperature The material must maintain its properties within a typical operating temperature range for electronic components for instance 20C to 85C Kirpik et al 2023 Free Variables 1 Material Choice This is the primary free variable we seek to determine 2 CrossSectional Shape and Area A While the length L is fixed the crosssectional geometry eg width b and height h of a rectangular section can be varied to meet the stiffness and strength constraints This is an important free variable in the derivation 22 The Loading Case and Geometric Model To analyze the component we must model its geometry and loading Geometric Model The relay arm is best approximated as a cantilever beam Vidyadhara et al 2022 It is fixed at the pivot point and free at the end where the magnetic force is applied and the contacts are located For derivation we will assume a simple rectangular crosssection of width b and height h This is a common and effective shape for such components Loading Case The arm is subjected to a cyclic point load F applied at its free end at length L from the pivot This force is the magnetic attraction from the energized coil When the coil is deenergized the force is removed and a return 5 spring or the inherent stiffness of the contacts pushes the arm back This creates a fully reversed or repeated stress cycle making fatigue a primary failure mode The loading is dynamic not static 6 23 Key Assumptions and Justifications To make the problem tractable several welldefended assumptions are necessary 1 Response Time and Natural Frequency We assume that minimizing response time is equivalent to maximizing the fundamental natural frequency ω of the arm A component with a higher natural frequency can oscillate and settle more quickly leading to a faster actuation Nayfeh and Mook 2024 This is a standard approach in the design of highspeed mechanical systems as it prevents resonance with any driving frequencies and allows for rapid state changes 2 Dominant Failure Mode is Fatigue We assume that for a properly designed arm ie one that meets the stiffness constraint the primary mode of failure over its lifetime will be highcycle fatigue due to the millions of actuation cycles AVATEFFAZELI et al 2022 We will neglect other failure modes like creep as the operating temperatures are moderate and the static loads are low 3 Simplified Loading We model the magnetic force as a point load F at the end of the beam The force may be distributed but the point load model provides the maximum bending moment and stress at the cantilever root Zhang and Fu 2023 representing a conservative worstcase scenario for design 4 Isotropic Material Properties During the initial derivation and screening we will assume the materials are isotropic properties are the same in all directions This is valid for unfilled polymers and ceramics For composites like GFRP which are anisotropic this assumption will be revisited during the detailed comparison stage where the orientation of fibers becomes a critical design parameter Zhao et al 2024 5 Small Deflections We assume the arm operates within the regime of small deflection theory where linear elastic behavior holds This is a valid assumption as large deflections would imply a poorly designed overly flexible arm that would fail to actuate the contacts reliably 7 24 Summary of Design Requirements Component Relay Arm Armature Function Pivot to actuate electrical contacts Objective Minimize response time equivalent to Maximize natural frequency ω Constraints 1 Fatigue strength σe operating stress σmax 2 Deflection δ δmax 3 High electrical resistivity 4 Fixed length L 5 Operation from 20C to 85C Free Variables 1 Material choice 2 Crosssectional area A and shape 3 Derivation of the Material Index The goal of this section is to derive a performance indexa group of material properties that must be maximized to achieve our design objective 31 Translating the Design Objective into a Performance Equation As established our objective is to maximize the fundamental first mode natural frequency ω of the relay arm For a cantilever beam the natural frequency is given by the standard formula Yuan Zhuang and Xu 2024 ω C K m ₁ eff Where ω is the fundamental natural frequency in rads K is the stiffness of the beam at the point of interest K Fδ meff is the effective mass of the beam 8 C is a constant that depends on the boundary conditions for a cantilever beam ₁ it incorporates factors from the mode shape A more direct form for the fundamental frequency of a cantilever beam of length L is ω β ² EI ₁ ρAL ⁴ 1 Where β ² is a constant for the fundamental mode of a cantilever beam ₁ β 1875 so ₁ β ² 352 Ahiwale ₁ et al 2022 E is the Youngs Modulus of the material a material property I is the second moment of area of the beams crosssection a geometric property ρ is the density of the material a material property A is the crosssectional area a geometric property L is the length of the beam a fixed functional requirement Our goal is to maximize ω 32 Formulating the Objective Function From Equation 1 we can see that our objective is to maximize the term EI ρAL ⁴ Lets analyze the components Material Properties E Youngs Modulus ρ Density Geometric Properties I Second moment of area A Crosssectional area Functional Requirement L Length which is fixed The geometry I and A is a free variable We can make the arm thicker or thinner However we cannot simply make it infinitely thick as this would increase mass and likely violate other constraints The key insight of the Ashby method is to use a constraint to eliminate the free geometric variable 9 Lets assume a rectangular crosssection of width b and height h Area A b h Second moment of area I b h³ 12 Substituting these into Equation 1 ω β ² E bh³12 ₁ ρ bh L ⁴ Now we simplify the terms inside the square root ω β ² E h² 12 ₁ ρ L ⁴ Pulling the geometric and fixed terms out of the square root ω β ² h 12 L² ₁ E ρ 2 33 Isolating Material Geometry and Functional Parameters Equation 2 neatly separates the different aspects of the design ω Functional Part Geometric Part Material Part Functional Part β ² 12 L² This part is determined by the components ₁ function a cantilever beam of fixed length L It is constant for this problem Geometric Part h This is the height of the beam our free geometric variable Material Part E ρ This combination of material properties is what we need to maximize At this point we have a choice We could simply declare that the material index is E ρ However the geometry term h is still free A robust derivation links this free variable to a constraint While the stiffness constraint δ δmax could be used in this case the design is geometry limited This means we can select any geometry value of h we want if it meets the stiffness and strength constraints The objective function 10 Equation 2 shows that for any chosen material increasing h will always increase the natural frequency Therefore the task simplifies to get the highest possible natural frequency we should choose the material that provides the highest value of E ρ Maximizing E ρ is mathematically identical to maximizing the simpler index M E ρ This index is known as the specific stiffness or specific modulus of a material 34 The Final Material Performance Index The material index to be maximized to achieve the objective of minimum response time for a relay arm of a given length and free crosssection is M E ₁ ρ This index tells us to search for materials that are simultaneously very stiff high E and very light low ρ These materials will vibrate at the highest possible frequency for a given geometry thus providing the fastest possible response time The other constraints fatigue strength electrical resistivity will be used as screening filters to narrow the field of potential materials before we apply this index 4 Material Screening and DownSelection using Ashby Charts With the material index M E ₁ ρ derived we can now use Ashby property charts to systematically search for the best materials This process is divided into two stages screening and ranking optimization We will use the Youngs Modulus vs Density Ashby chart as both properties are present in our index 11 41 Stage 1 Screening with Hard Constraints Before we look for the material with the highest Eρ we must first eliminate all materials that fail to meet our nonnegotiable constraints The relay arm must be an electrical insulator and this is a critical safety and functional requirement We need to set a limit on electrical resistivity considering a good insulator has a resistivity greater than 10¹ ⁰ Ωm Mitolo 2025 pp 38 Action On the Ashby chart this constraint immediately eliminates the entire class of Metals and Alloys They are conductors This is a massive reduction in the search space We are left with Polymers Ceramics Composites and some natural materials The arm must not fail in fatigue This requires the materials fatigue strength or endurance limit σe to be greater than the maximum bending stress experienced in service σmax While σmax depends on the final geometry and applied force we can set a reasonable minimum requirement for a small electromechanical component A conservative minimum fatigue strength of σe 30 MPa is a suitable starting point This value is high enough to ensure durability but not so high as to exclude viable polymers Olugbade et al 2021 Action We apply this limit on a Strength vs Density chart or by consulting property data for the material classes that survived the first screen Many commodity polymers like PE PP and elastomers will be eliminated as their fatigue strengths are too low Engineering polymers Nylon PC PEEK technical ceramics Alumina Silicon Nitride and composites GFRP CFRP generally meet this requirement Chavez et al 2022 The material must function from 20C to 85C This constraint eliminates materials that become brittle at low temperatures or soften at high temperatures Most engineering polymers ceramics and composites are suitable within this range It does however screen out some lowgrade polymers and waxes Akman and Sadhu 2024 12 42 Stage 2 Optimization using the Material Index After screening we are left with candidate materials primarily from the Polymer Ceramic and Composite families We now apply our derived material index M E ₁ ρ to rank these survivors On a loglog plot of Youngs Modulus E vs Density ρ the index M can be ₁ represented as a selection line Taking the logarithm of our index equation M E ₁ ρ logM logE ₁ ρ logM logE log ₁ ρ logE logρ logM ₁ This is the equation of a straight line on the loglog chart with a slope of 1 To maximize M we need to maximize the yintercept logM This is achieved by ₁ ₁ drawing a line with a slope of 1 and moving it as far as possible to the topleft of the chart as this region represents high E and low ρ Yamaguchi and Yang 2022 The image below shows a representative E vs ρ Ashby chart with the screening and ranking steps illustrated Figure 1 Ashby Chart 13 Source Wikimedia Commons 2025 43 Identification of Candidate Material Classes By moving the selection line to the topleft we can identify the material families that offer the best performance for our objective 1 Engineering Ceramics Materials like Alumina Al O Silicon Carbide SiC ₂ ₃ and Silicon Nitride Si N are located very high on the chart and far to the left ₃ ₄ They offer exceptionally high Eρ values 2 Composites CarbonFibre Reinforced Polymers CFRP and GlassFibre Reinforced Polymers GFRP also occupy a prime position in the topleft Their combination of a light polymer matrix with stiff reinforcing fibers gives them excellent specific stiffness often on par with or exceeding that of metals 3 HighPerformance Engineering Polymers Some advanced polymers like Polyether ether ketone PEEK and certain Polyamides Nylons while not as high as ceramics or composites still offer a good balance of properties and lie in the upper region of the polymer family Based on this analysis we will select one representative material from each of these three promising classes for a more detailed comparison 5 Detailed Comparison of Candidate Materials The Ashby chart analysis has successfully narrowed the vast universe of materials down to three promising classes We now select a representative candidate from each class for a rigorous headtohead comparison to make the final selection 51 The Shortlisted Candidates 1 Alumina Aluminum Oxide Al O ₂ ₃ A leading representative of the Engineering Ceramics class It is widely available relatively lowcost for a ceramic and known for its hardness and high modulus Boldin et al 2021 14 2 Polyether ether ketone PEEK A highperformance semicrystalline thermoplastic representing the best of the Engineering Polymers It is renowned for its excellent mechanical properties thermal stability and chemical resistance Zol et al 2023 3 GlassFibre Reinforced Polymer GFRP A prime example of the Composites class Specifically we will consider a standard epoxy matrix with Eglass fibers It is chosen over CFRP for its lower cost and better electrical insulation properties carbon fibers can be slightly conductive Zhang et al 2023 52 Quantitative Comparison using a Merit Rating Chart To compare these materials objectively we will use a table of key properties The properties include our primary index Eρ our constraint properties fatigue strength resistivity and other important practical considerations like fracture toughness cost and manufacturability Property Alumina Al O ₂ ₃ PEEK Unfilled GFRP Epoxy 60 E Glass Units Importance to Design Performance Properties Youngs Modulus E 380 38 45 longitudinal GPa High is better Stiffness Density ρ 3800 1300 1900 kgm ³ Low is better Lightweight Material Index M Eρ ₁ 100 29 237 GPa kgm ³ x10 ³ Maximize Primary Objective Constraint Secondary Properties Fatigue Strength σe 10 cycles ⁷ 150 80 250 tensiontension MPa Must be σoperating eg 30 MPa Electrical Resistivity 10¹⁴ 10¹⁴ 10¹⁴ Ωm Must be high Insulator Fracture 2 4 25 35 25 35 MPam¹² High is better 15 Toughness KIc Resists Cracks Max Service Temp 1000 240 150 C Must be 85C Practical Considerations Relative Cost Raw Material Medium Very High LowMedium Low is better Manufacturability for small complex part Difficult sintering grinding Excellent injection molding Good compressioninjection molding Ease of processing reduces final cost Granta Design 2020 53 Qualitative Discussion of Candidates The quantitative data tells only part of the story A qualitative analysis is essential to understand the practical tradeoffs On paper Alumina is the clear winner based purely on the material index M ₁ 100 Its extremely high modulus combined with a moderate density gives it unparalleled specific stiffness It also has excellent fatigue and temperature resistance However its Achilles heel is its catastrophically low fracture toughness KIc Alumina is a classic brittle ceramic This means it has virtually no ability to tolerate microscopic flaws In a dynamic application with millions of stress cycles and potential for minor impacts during assembly or operation a tiny crack could propagate almost instantaneously leading to complete failure without warning Furthermore manufacturing small precise Alumina parts is difficult and expensive typically requiring powder pressing hightemperature sintering and diamond grinding to achieve final dimensions Kishore et al 2022 Verdict Too brittle and difficult to manufacture for this application The risk of sudden failure is too high PEEK is an impressive material While its Eρ index is the lowest of the three it is still very good for a polymer Its key advantages are its excellent fatigue strength and its relative toughness which is comparable to Alumina but in a material that yields before breaking Its greatest strength is manufacturability PEEK can be 16 precision injection molded into complex net shapes drastically reducing manufacturing costs for highvolume production compared to machining ceramics citation 27 However its raw material cost is very high often making it prohibitive unless its specific combination of properties like extreme chemical resistance or high temperature performance which we dont fully need here is essential Verdict A very strong but potentially overengineered and expensive candidate GFRP strikes an exceptional balance Its specific stiffness M 24 is an order of magnitude ₁ better than PEEK and is competitive with many metals though not as high as Alumina Its standout feature is its combination of properties Excellent Fatigue Strength Composites are known for their superb performance under cyclic loading often outperforming metals High Fracture Toughness The composite structure with fibers embedded in a polymer matrix provides multiple mechanisms for arresting crack growth The toughness of GFRP is an order of magnitude higher than that of Alumina making it far more reliable and damagetolerant Good Manufacturability GFRP components can be produced efficiently using methods like compression molding or injection molding for shortfiber variants allowing for complex shapes Low Cost Glass fiber and common polymer resins like epoxy or polyester are relatively inexpensive materials making GFRP a very costeffective solution The main complication is its anisotropy its properties are best along the direction of the fibers However this can be used as a design advantage By aligning the long glass fibers along the length of the relay arm the direction of maximum bending stress we can maximize performance precisely where it is needed This extreme brittleness is particularly dangerous in a highcycle fatigue application where any microscopic manufacturing flaw or surface scratch can act as a stress concentrator leading to rapid crack initiation and catastrophic failure with little or no warning 54 Selection Rationale 17 Comparing the three candidates Alumina is rejected due to its brittleness low fracture toughness which poses an unacceptable risk of catastrophic failure in a dynamic component PEEK is a viable but very expensive option Its performance does not justify the significant cost increase over GFRP for this specific application GFRP emerges as the optimal choice It offers a superior combination of high specific stiffness outstanding fatigue resistance excellent fracture toughness damage tolerance low cost and good manufacturability 6 Final Material Choice GlassFibre Reinforced Polymer GFRP 61 Justification of Final Selection Based on the comprehensive analysis performed in the preceding sections the final material selected for the electromagnetic switch relay arm is GlassFibre Reinforced Polymer GFRP specifically a composition of continuous Eglass fibers aligned longitudinally within an epoxy resin matrix This choice is justified by the following key points which directly address the design objectives and constraints 1 Optimized Objective Response Time GFRP possesses a very high specific stiffness Eρ second only to highperformance ceramics This ensures a high natural frequency leading to a fast response time directly meeting the primary design objective 2 Fatigue Resistance GFRP exhibits excellent resistance to fatigue failure a critical requirement for a component cycled millions of times Its fatigue endurance limit is superior to most engineering polymers and many metals guaranteeing a long and reliable service life 3 Damage Tolerance Toughness This is the deciding factor over ceramics GFRPs high fracture toughness means it can withstand minor impacts and resist the propagation of microcracks preventing the sudden catastrophic failure characteristic of brittle materials like Alumina This ensures the relay fails safely or not at all 18 4 Constraint Compliance GFRP is an excellent electrical insulator easily meeting the resistivity requirement It also maintains its mechanical properties well within the specified service temperature range 5 CostEffectiveness Compared to both PEEK and machined Alumina GFRP offers a significantly lower cost for the high level of performance it delivers making it an economically sound choice for mass production 6 Design Flexibility The anisotropic nature of GFRP allows for tailored design where fiber orientation can be optimized to align with the principal stress directions along the length of the cantilevered arm maximizing stiffness and strength exactly where needed 62 Potential Manufacturing Considerations The chosen manufacturing process would likely be pultrusion to create stock rods with continuous aligned fibers followed by a cutting and shaping process Alternatively for more complex arm geometries compression molding of a pre impregnated composite sheet prepreg would be ideal This process uses heat and pressure to cure the part into its final net shape ensuring high fiber volume fraction and minimal voids leading to optimal mechanical properties Quality control would be essential to ensure proper fiber alignment and full curing of the resin 7 Sustainability Analysis A responsible engineering choice goes beyond just technical performance and cost it must also consider the environmental and societal impact of the material throughout its life cycle 71 Sustainability of the Design Choice Performance and Longevity At first glance a polymer composite derived from fossil fuels does not seem like a sustainable choice However sustainability can be viewed through the lens of the products entire life cycle The justification for selecting GFRP is based on inuse performance and longevity A highly efficient fast and reliable relay contributes to the energy efficiency 19 of the larger system it controls More importantly its exceptional fatigue resistance and durability mean the component will not need to be replaced for a very long time A product that lasts significantly longer reduces the total material and energy consumption associated with manufacturing and distributing replacements over the lifetime of the host device Therefore choosing a highperformance material like GFRP which extends the products life is a form of sustainable design 72 Resource Management We must analyze where the constituent materials for GFRP come from Glass Fibers The primary raw material for Eglass fibers is silica sand which is one of the most abundant minerals on Earth Other components include limestone and soda ash which are also widely available The extraction of these minerals involves quarrying which has a local environmental impact but does not face resource scarcity issues Epoxy Resin The polymer matrix is the more problematic component Epoxy resins are thermosetting polymers derived from feedstocks like epichlorohydrin and bisphenolA which are produced from crude oil This makes the matrix dependent on a nonrenewable fossilfuel resource This is the primary sustainability drawback of the material Research into biobased epoxy resins is ongoing but they are not yet as commercially mature or highperformance 73 Environmental Impact of Manufacturing The production of GFRP has several environmental considerations Embodied Energy The manufacturing process involves melting sand to create glass fibers and synthesizing the polymer resin both of which are energy intensive However the embodied energy of GFRP is generally lower than that of primary aluminum and significantly lower than that of engineering ceramics like Alumina which require extremely hightemperature sintering often 1600C 20 Emissions The synthesis of epoxy resins can involve hazardous chemicals During the curing process of the composite volatile organic compounds VOCs can be released although modern manufacturing facilities use closed systems and scrubbers to minimize these emissions 74 EndofLife EoL Plan The endoflife phase is the most significant challenge for thermoset composites like GFRP Because the polymer matrix is crosslinked it cannot be simply melted and remolded like a thermoplastic 1 Current Status The vast majority of GFRP waste currently goes to landfill This is not a sustainable solution 2 Recycling Options Several EoL technologies are emerging though they face economic and logistical hurdles citation 35 o Mechanical Recycling The composite is ground into a powder or short fibers This material can be used as a filler or reinforcement in other products eg concrete asphalt or lowergrade plastics This is technically downcycling as the high mechanical properties of the original aligned fibers are lost o Thermal Recycling Pyrolysis The composite is heated in an oxygen free environment This breaks down the polymer matrix into oils and gases that can be used as fuel energy recovery and it recovers the glass fibers The recovered fibers retain much of their strength and can be repurposed into new composites o Chemical Recycling Solvolysis This process uses solvents at high temperatures and pressures to chemically dissolve the polymer matrix allowing for the recovery of both the glass fibers and the chemical constituents of the resin This is a promising but currently expensive and less mature technology Proposed EoL Plan for the Relay Arm 21 Design for Disassembly The relay should be designed so the arm can be easily separated from the metallic components Material Labeling The arm should be labeled with the standard composite material code to facilitate sorting Producer Responsibility A takeback program could be established where the manufacturer partners with a specialized composite recycling facility that employs pyrolysis or solvolysis to recover value from the endoflife components 8 Conclusion This report has successfully executed a comprehensive materials selection process for a highperformance electromagnetic relay arm using the Ashby methodology The primary design objective of minimizing response time coupled with critical constraints of fatigue life stiffness and electrical insulation led to the derivation of a material performance index of M E ₁ ρ Through a systematic process of screening and ranking using Ashby charts three classes of materials engineering ceramics highperformance polymers and composites were identified as top performers A detailed comparison of representative candidates Alumina PEEK and GFRP weighed their technical merits against practical considerations of fracture toughness manufacturability and cost While Alumina offered the highest theoretical performance it was rejected due to its inherent brittleness which poses an unacceptable risk of catastrophic failure PEEK was found to be a capable but overly expensive solution GlassFibre Reinforced Polymer GFRP was ultimately selected as the optimal material It provides an outstanding and balanced profile of high specific stiffness exceptional fatigue strength superior damage tolerance low cost and proven manufacturability The sustainability of GFRP was also considered While its reliance on fossil fuelbased resins and endoflife challenges are notable drawbacks its selection is justified by the enhanced performance energy efficiency and extended service life it provides to the final product A forwardlooking endoflife plan involving emerging recycling technologies was proposed to mitigate its environmental impact In conclusion GFRP represents the most robust reliable and wellrounded engineering solution for this demanding application 22 23 9 References Ahiwale D Ingole S Raut M Rathod A and Gedam R 2022 Modal analysis of cracked cantilever beam using ANSYS software Materials Today Proceedings 56 pp 165170 doi 101016jmatpr202112181 Akman A and Sadhu A 2024 Recent development of 3Dprinting technology in construction engineering Practice Periodical on Structural Design and Construction 291 03123005 doi 101061PPSCFXSCENG1405 Ashby MF 2011 Materials Selection in Mechanical Design 4th edn Oxford ButterworthHeinemann Avateffazeli M Zuo G Zhao Y Zhang Y and Huang HZ 2022 Very high cycle fatigue at elevated temperatures a review on high temperature ultrasonic fatigue Journal of Space Safety Engineering 94 pp 488512 doi 101016jjsse202209006 Boldin MS Shishkin AV Firsov EV Shishkin AA Smirnov IV Golikov DA and Fedorov AV 2021 Review of ballistic performance of alumina comparison of alumina with silicon carbide and boron carbide Ceramics International 4718 pp 2520125213 doi 101016jceramint202105283 Chavez LA Ibave P Hassan MS HallSanchez SE Billah KMM Leyva A Marquez C Espalin D Torres S Robison T and Lin Y 2022 Lowtemperature selective laser sintering 3D printing of PEEKNylon blends impact of thermal post processing on mechanical properties and thermal stability Journal of Applied Polymer Science 13923 52290 doi 101002app52290 Granta Design 2020 CES EduPack Software Computer program Cambridge Granta Design Kirpik MG Demir H Yanardağ E and Keskin MG 2023 Application of Ashby method for optimization of high strength low priced bucket for silo elevators Osmaniye Korkut Ata Üniversitesi Fen Bilimleri Enstitüsü Dergisi 63 pp 22132233 doi 1047495okufbed1235492 24 Kishore K Sinha MK Rajesh S Singh A and Korkmaz ME 2022 A comprehensive review on the grinding process advancements applications and challenges Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science 23622 pp 1092310952 doi 10117709544062221110782 Liu G Li Z Zhang K Xu Y and Li J 2022 A new electromagnetic structure of relay with composite armature containing permanent magnet in Annual Conference of China Electrotechnical Society Springer Nature Singapore Singapore pp 370376 Magesh PR Sankari HP Lokeshwaran H and Ezhilarasan K 2022 IoT based industrial automation for various load using ATmega328p microcontroller 2022 6th International Conference on Intelligent Computing and Control Systems ICICCS pp 471475 doi 101109ICICCS5371820229788258 Mitolo M 2024 Principles and Practices of Electrical Safety Engineering Ensuring Protection in Electrical Systems Boca Raton CRC Press Nayfeh AH and Mook DT 2024 Nonlinear Oscillations New York John Wiley Sons Olugbade TO Akpan EI Afolalu SA Fayomi OSI and Okeniyi JO 2021 A review on the corrosion fatigue strength of surfacemodified stainless steels Journal of the Brazilian Society of Mechanical Sciences and Engineering 439 421 doi 101007s40430021031405 Pimenta S and Pinho ST 2011 Recycling of thermoset composites Composites Part A Applied Science and Manufacturing 426 pp 579593 doi 101016jcompositesa201101018 Vidyadhara BV Praveen TA Murthy MK and Ghose D 2022 Design and integration of a drone based passive manipulator for capturing flying targets Robotica 407 pp 23492364 doi 101017S026357472100234X Xiang S Zhao C Hao S Li K and Li W 2023 A reliability evaluation method for electromagnetic relays based on a novel degradationthresholdshock model with twosided failure thresholds Reliability Engineering System Safety 240 109549 doi101016jress2023109549 25 Yamaguchi K and Yang J 2022 Analysis of origamibased mechanical metamaterials via extended three dimensional Ashby chart Active and Passive Smart Structures and Integrated Systems XVI 12043 1204313 doi 101117122612745 Yuan M Zhuang J and Xu Z 2024 Modeling and analysis of coupled dynamics of relay considering collision bouncing in 2024 3rd Asia Power and Electrical Technology Conference APET IEEE Chengdu pp 3640 doi 101109APET61379202410526012 Zhang X and Fu X 2023 New theoretical models for the bending moment of thin walled beams under threepoint bending Applied Mathematical Modelling 121 pp 21 42 doi 101016japm202303024 Zhang M Li X Huang X Li M Li D and Qian C 2023 Improving dispersion of recycled GFRP fiber in cement mortar with sodium hexametaphosphate Cement and Concrete Composites 143 105232 doi 101016jcemconcomp2023105232 Zhao T Zhang J Shen Q Huang Y and Lei B 2024 Experimental research and theoretical prediction on mechanical properties for recycled GFRP fiber reinforced concrete Journal of Building Engineering 91 109643 doi 101016jjobe2024109643 Zol SM Tsoi JKH Zhang S Chow TW Cheung JYN and Mat NNN 2023 Description of poly aryletherketone materials PAEKs polyetheretherketone PEEK and polyetherketoneketone PEKK for application as a dental material a materials science review Polymers 159 2170 doi 103390polym15092170