Question

For proper design of a shaft, it should be designed on the basis of

• A. Maximum principal stress theory
• B. Maximum shear stress theory
• C. Both 1 and 2
• D. Maximum strain theory

Answer 1

Answer:

B. Maximum shear stress theory

Shaft should be designed based on the maximum shear stress theory. According to this theory, failure occurs when the maximum shearing stress reaches the failure value equal to that developed at yielding in an axial tensile or compressive test of the same material. This theory is well justified for ductile materials. The equation for design is $\sigma_{1} - \sigma_{2}\le (\sigma_{Y} / FOS)$ where $\sigma_{1}$ and $\sigma_{2}$ are maximum and minimum principal stress respectively, and $\sigma_{y}$ is the permissible stress