Question

A cold-rolled steel shaft is designed on the basis of the maximum shear stress theory. The Principal stresses induced at its critical section are 50 MPa and -50 MPa respectively. If the yield stress for the shaft material is 400 MPa, the factor of safety of the design is

• A. 3
• B. 4
• C. 6
• D. 2

Answer 1

Answer:

B. 4

Given: $\sigma_{1} = 50 Mpa$, $\sigma_{2} = - 50 Mpa$, $\sigma_{y} = 400 Mpa$: $\sigma_1 -\sigma_2 \le (\frac {\sigma_y}{F.O.S} ) \Rightarrow 50 - (- 50) = \frac{400}{FOS}\Rightarrow FOS = 4$