In this example, suppose that you need to design an accelerated life test for a mechanical component. The single acceleration factor is torque, and the normal use stress is 35 Nm (newton meters). You want to estimate the time at which 10% of the units fail at the normal use stress. You construct a failure probability optimal ALT test.
Your test plan has the following characteristics:
• A total of 100 units are available for testing.
• The life distribution is assumed to be Weibull.
• The life-stress relationship is given by the logarithmic transformation.
• You plan to test torque at three stress levels: 50, 75, and 100 Nm.
• You have prior knowledge to predict initial failure times at the test levels. See Obtain Prior Estimates.
• The test will continue for 5,000 cycles.
• You will monitor the process for failures on a continuous basis.