Which material failure type involves twisting or torque?

• A. Tension
• B. Compression
• C. Torsion (Twisting)
• D. Bending

Answer: (C)

Twisting or torque on a part causes torsion, the failure mode that arises when a body is loaded by a moment about its axis. Pure torsion induces shear stresses that vary with radius and are greatest at the outer surface, so the material fails by twisting once those shear stresses exceed its shear strength. This is different from tension, which pulls along the axis and elongates the part; compression, which pushes along the axis and shortens it; and bending, which creates tension on one side and compression on the other due to curvature. So the material failure type involving twisting or torque is torsion.