Homework 5 FOSM

1. The limit-state function of a shaft in a speed reducer is defined by the difference between the strength and the maximum equivalent stress. It is given by

where

mm, the diameter of the shaft

 mm, the length of the shaft

 the external force

 the external torque

the yield strength

The distributions of the independent random variables are given below.

Table 1 Distributions

Variables	Mean	Std	Distribution
External force	2000 N	220 N	Normal
Torque	450 N·m	50 N·m	Normal
Strength	250 MPa	30 MPa	Normal

Use FOSM to calculate the probability of failure.