Which term refers to latent stress remaining in a member after it has been formed to its final shape?

• A. Resurfacing
• B. Rib
• C. Residual Stress
• D. Rigid Frame

Answer: (C)

Latent stress remaining after forming a member is called residual stress. It comes from the manufacturing process itself—when metal is shaped, stretched, bent, or cooled unevenly, different parts deform plastically and then lock in internal forces as the piece finishes cooling. Once the final shape is reached and external loads are removed, these internal stresses persist, which can be tensile in some zones and compressive in others. This residual stress affects how the member behaves under service: it can cause distortion, affect fatigue life, and influence how the part responds to subsequent machining or welding. Methods like heat treatment, annealing, or surface methods such as shot peening are used to relieve or redistribute residual stresses. The other terms don’t describe internal stresses: resurfacing relates to surface finish, rib is a structural feature, and a rigid frame is a type of structural configuration, not a stress state.