Test Design Assistant

Weibull++ includes test design tools that provide ways to design reliability tests as well as evaluate and compare proposed test designs. Three of these tools can be accessed by choosing Home > Insert > Test Design.

The Test Design Assistant will appear and ask you to select one of the following:

• Reliability Demonstration Test solves for values associated with a specified test design such as required test time, required sample size, demonstrated reliability and confidence level.

• Expected Failure Time Plot determines what failure times you can expect in a test with a given sample size. Because you can display actual failure times on the plot, it is especially useful for determining whether a test is proceeding as expected.

• Difference Detection Matrix shows how much test time is needed to detect a statistically significant difference in life between two product designs when the data are obtained from reliability life tests and then analyzed with a  life data or life-stress data folio.

Note that in addition to the tools discussed in these topics, the software includes two other tools that can assist you in designing reliability life tests:

• ALTA Test Plan recommends a test plan for accelerated life testing data analysis. The recommended plan will include information about what stress levels to use in the test, as well as what sample sizes to use for each stress level.

• SimuMatic allows you to use simulation-based methods to experiment with various testing scenarios. For example, you could try to improve a given test plan by running a simulation of the test with a smaller sample size and seeing whether the more conservative plan would still allow you to meet your test goals. (See Designing Reliability Tests with SimuMatic.)