고체역학 (Gere) — Stresses in Beams (Basic Topics): Problem 5.4-6

5.4-6 A bar of rectangular cross section is loaded and supported as shown in the figure. The distance between supports is \( L = 1.75 \) m, and the height of the bar is \( h = 140 \) mm. The deflection at the midpoint is measured as 2.5 mm. (a) What is the maximum normal strain \(\epsilon\) at the top and bottom of the bar? (b) If allowable strain \(\epsilon_a = 0.0006\) and the deflection cannot exceed 4.3 mm, what is the maximum permissible length of the bar?