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Engenharia Civil ·

Resistência dos Materiais

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Lista de Exercícios 6\nEsforço normal\n\n1)\n∑MA = 0 → -500.3 + 2NBD = 0\nNBD = 750 ... compressão\n6. lema: l = 1/2 A = (g√3)/2 l²/x = 3√3 l²/l₁ ≤ CE/d\nv₁ = 2NBD/3√3l²\nσ₁ = 0\nσ₂ = 0\nσ₃ = 0\n\n2)\nvT = -1600 kg/m²\nσC = 600 kg/m²\nE = 1000000 kg/m²\nF = 100000 kg/m²\n\nN1 = 0,92\nAAC = ?\nMAB = ?\nd₀ = 2\n\\rightarrow Tração\n∑Fyc = 0 → N1 - 500 - N3 = 0 \nN3 = 100 kg\nCompresão\n∑MI = 0 → -1000 - (√2/2) → N2 = 0 → N2 = 1414,21 kg\nCompressão σAC = N2/AAC\nσ₁ = 0\nσ₂ = 0\nσ₃ = N2/AAC\n\nεAB = 1/E σ\nεAB = 1/E N1/lAB\n∴ lAB N1 = ΔlAB/EA\nΔlAB = 0,0641m\n\nεCD = 1/E N3/A\nεCD = N3/F.A = 4,2426.10⁵\n\n3)\nD = 0,2m\nP = 60 kg\n\nσ₁ + σ₂ A = 60\n\nE* + E2 A = 60\n\nF₁ + F₂ = 60 kg\n\nΔl₁ = Δle + 0,1\nl₁ = 400 cm\nl₂ = 400,1 cm Δl₂ (l₂ + l₁)/(l₁ + l₂) = 60,4/(EF D²) - 0,1/l₁\nΔl₂ = 240 l₂/(π D² E) - l₂/(l₂ + l₁)\n= 0,1319 cm\nF1 = F.A (Δl₂ + 0,1)/l₁ = E.πD² (Δle + 0,1)/l₁ = 38,2494 kg\nF₂ = 21,7506 kg\n\n∴ ΔlCD - ΔlBC - ΔlAB = Δl\nE = 100000 HPa\nlcd = 1 m = 100 cm\nDCD = 45 cm\n\nlcd = 12 m = 1200 cm\nDAB = 5 cm\n\ns = lcd FE/(π (P²/2)²/4)\n= 4lcd FCD / (π E DCD²) = 9,86588 cm\nΔlBC = 4lcd FBC / (π E DBC) = 0,91977 cm\nΔlAB = 4lAB (100 - 30) / (π E DAB) = 0,053418 m\nΔl = 0,78913 cm ΣMA = 0 ↔ 2FDB - 8.80 + 4FEC = 0\n2FDB + 4FEC = 3.10 ↔ FDB + 2FEC = 3.40\nνL = F1 ε1 ρ1 A = F1 Δl A\nΔlDB = ΔlEC / 2 ↔ ΔlFC = 2ΔlDB\nE ΔlDB A / l = 120\n5FDB A / l = 5FDB = 120 ↔ FDB = 24 kN\nFEC = 120 - FDB / 2 = 48 kN\nIFy = 0 ↔ FA + FEC + FDB - 80 = 0 ↔ PA = 8 kN\nΔla = Δlc\n(Fe - Fc)\n1 / √EA = 1 / √EC ↔ √VA = Fe / Fc\n√VA A + √VC A = 1500\nFA ρA 0 + √VC A = 1500\n√VC (EA A / Fc + AC) = 1500 ↔ √VC = 1500 → (EA A + AC) / Fc\n√VA = 6.09890 kgf/cm²\nΔl = √VA . l / FA = -0.09148 m F1 + F2 + F3 = 5000\n↔ F1 = F3\n2F1 + F2 = 5000 ↔ 2F F1 / F2 + 1 = 5000\nF2 = 5000 / (2F1 / F2 + 1) = 4411.76447 kgf\nF2 = √(VC A) = √(VC π d² / F2 = 3.56047 ΣFy = 0 ↔ cos 45° P1 + P2 + cos 45° P3 = P\nΣFx = 0 ↔ P1 = P3\n2 cos 45° P1 + P2 = P ↔ P2 = √2P1 + P2 = P\nΔl cos 45° - Δl = 0\nl1 Eρcos 45° - l2 Eρ2 = 0\nl1 Eρcos 45° - (l2 cos 45°) Eρ2 = 0\nP2 = P3 = 0.34315P