Which type of stress cannot be produced by mechanical forces on a structure?

• A. Tensile
• B. Shear
• C. Elastic
• D. Compressive

Answer: (C)

When a structure carries a load, the internal forces that develop in its members are actual stress states: tension (pulling along the length), compression (pushing along the length), and shear (layers sliding past each other). Elastic describes how the material responds to those stresses—whether the deformation is recoverable when the load is removed. It’s a behavior or property of the material, not a distinct type of stress. So you can have tensile, compressive, or shear stress, and the material can respond elastically within its elastic range. There isn’t a separate “elastic stress” type that forces can produce, which is why this option is the correct choice.