Recomendados
Recomendados
Mais conteúdo relacionado
Semelhante a Real Life Example 01.pptx
Semelhante a Real Life Example 01.pptx (20)
Último
Último (20)
Real Life Example 01.pptx
- 1. Real Life Example in Mechanics of Material's By Sina Abedini n
- 2. ELEMENTARY STRESS SYSTEMS 1.Stress and strain in uni -axial solid hollow bars Explain: Work through the example below: An iPod ; with a mass 30 grams in dangled its earplug cable. a)Assuming that copper wire of diameter 0.40mm inside the cable carries the entire load ; evaluate the stress in the wire due to the weight of the iPod b)If the wire in (a) is1.50m long ; by how much will it stretch? c)Assuming that the plastic insulation ; which fits snugly over the wire and has an external diameter of 1mm ; carries the entire load ; evaluate the stress in insulation due to the weight of iPod d)If the insulation is made from uPVC calculate the extension of the insulation in circumstances described in (c)
- 3. 𝑎)𝜎 = 𝐹 𝐴 = 𝑚𝑔 𝜋 4 𝑑2 = 30 × 10−3 × 9.81 𝜋 4 × (0.4 × 10−3)2 0.4mm 𝐹 = 𝑚𝑔 = 30 × 10 −3 × 9.81 2.3 × 106 𝑁 𝑚2 1.5m 𝑏)δ = 𝑃𝑙 𝐴𝐸 = 𝑚𝑔 × 𝑙 𝜋 4 𝑑2 × 𝐸 = 30 × 10−3 × 9.81 × 1.5 𝜋 4 × (0.4 × 10−3)2× 110 × 109 31.9 × 10−6 𝑚
- 4. 0.4mm 1mm 1.5m 𝐹 = 𝑚𝑔 = 30 × 10 −3 × 9.81 0.2mm c)𝜎 = 𝐹 𝐴 = 𝑚𝑔 𝜋 4 𝑑0 2 −𝑑1 2 𝐸 = 30×10−3×9.81 𝜋 4 (0.0012−0.0042) 0.29 𝑁 𝑚2 𝑑)𝛿 = 𝑃𝑙 𝐴𝐸 = 𝑚𝑔𝑙 𝜋 4 𝑑0 2 − 𝑑1 2 𝐸 = 30 × 10−3 × 9.81 × 1.5 𝜋 4 (0.0012 − 0.0042) × (2 × 109) 3.35 × 10−4𝑚