고체역학 (Gere) — Axially Loaded Members: Problem 2.7-5

2.7-5 Determine the strain energy per unit volume (units of \( \text{kN/m}^2 \)) and the strain energy per unit weight (units of m) that can be stored in each of the materials listed in the accompanying table, assuming that the material is stressed to the proportional limit. Material Weight Density (\( \text{kN/m}^3 \)) Modulus of Elasticity (\( \text{GPa} \)) Proportional Limit (\( \text{MPa} \)) Mild steel 77.1 207 248 Tool steel 77.1 207 827 Aluminum 26.7 72 345 Rubber (soft) 11.0 2 1.38