고체역학 (Gere) — Axially Loaded Members: Problem 2.5-4

2.5-4 A steel rod of 15-mm diameter is held snugly (but without any initial stresses) between rigid walls by the arrangement shown in the figure part a. (For the steel rod, use \(\alpha = 12 \times 10^{-6}/^{\circ}\text{C}\) and \(E = 200 \text{ GPa}\).) (a) Calculate the temperature drop \(\Delta T\) (degrees Celsius) at which the average shear stress in the 12-mm diameter bolt becomes 45 MPa. Also, what is the normal stress in the rod? (b) What are the average bearing stresses in the bolt and clevis at A and between the washer (\(d_w = 20 \text{ mm}\)) and wall (\(t = 18 \text{ mm}\)) at B? (c) If the connection to the wall at B is changed to an end plate with two bolts (see figure part b), what is the required diameter \(d_b\) of each bolt if the temperature drop is \(\Delta T = 38^{\circ}\text{C}\) and the allowable bolt stress is 90 MPa?