고체역학 (Gere) — Axially Loaded Members: Problem 2.4-10

2.4-10 A plastic rod \(AB\) of length \(L = 0.5 \text{ m}\) has a diameter \(d_1 = 30 \text{ mm}\) (see figure). A plastic sleeve \(CD\) of length \(c = 0.3 \text{ m}\) and outer diameter \(d_2 = 45 \text{ mm}\) is securely bonded to the rod so that no slippage can occur between the rod and the sleeve. The rod is made of an acrylic with a modulus of elasticity \(E_1 = 3.1 \text{ GPa}\), and the sleeve is made of a polyamide with \(E_2 = 2.5 \text{ GPa}\). (a) Calculate the elongation \(\delta\) of the rod when it is pulled by axial forces \(P = 12 \text{ kN}\). (b) If the sleeve is extended for the full length of the rod, what is the elongation? (c) If the sleeve is removed, what is the elongation?