Question

A machine component made of steel is subjected to a reversed bending stress of 300 MPa for 15% of the time, a reversed bending stress of 450 MPa for 35% of the time, and a reversed bending stress of 550 MP for 50% of the time. Determine the expected life of the component using the following:

a,, -500 N/mm²

Answer 1

To determine the expected life of the machine component, we need to calculate the fatigue life using the stress-life equation. We can calculate the expected life by multiplying the number of cycles at each stress level with its corresponding percentage of time, then summing the results.

Step-by-step explanation:

To determine the expected life of the machine component, we need to calculate the fatigue life using the stress-life equation.

The stress-life equation is given by:

N = A*(1/Stress)^B, where N is the number of cycles to failure, A and B are material constants. In this case, we have three different stress levels with corresponding percentages of time:

- Stress level of 300 MPa for 15% of the time
- Stress level of 450 MPa for 35% of the time
- Stress level of 550 MPa for 50% of the time

We can calculate the expected life by multiplying the number of cycles at each stress level with its corresponding percentage of time, then summing the results.

Let's calculate:

N_total = (N1 * P1) + (N2 * P2) + (N3 * P3)