고체역학 (Beer) — Stress and Strain—Axial Loading: Problem 2.103

2.103 Rod AB is made of a mild steel that is assumed to be elastoplastic with \(E = 200\text{ GPa}\) and \(\sigma_Y = 345\text{ MPa}\). 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.