고체역학 (Beer) — Stress and Strain—Axial Loading: Problem 2.104

2.104 Solve Prob. 2.103, assuming that the yield point of the mild steel is 250 MPa. (Context from Prob. 2.103: Rod AB is made of a mild steel that is assumed to be elastoplastic with \(E = 200 \text{ GPa}\) and \(\sigma_Y = 345 \text{ MPa}\) [Note: Use 250 MPa for this problem]. After the rod has been attached to the rigid lever CD, it is found that end C is 6 mm too high. A vertical force \(Q\) is then applied at C until this point has moved to position \(C'\). Determine the required magnitude of \(Q\) and the deflection \(\delta_1\) if the lever is to snap back to a horizontal position after \(Q\) is removed.) From Fig. P2.103: Rod AB: Length \(L = 1.25 \text{ m}\), diameter \(d = 9 \text{ mm}\). Lever CD: Pivoted at D. Distance \(BD = 0.7 \text{ m}\), distance \(BC = 0.4 \text{ m}\). Total length \(CD = 1.1 \text{ m}\).