For the latest version of JMP Help, visit JMP.com/help.


Publication date: 07/24/2024

Constant Stress ALT Plan Specifications

The second step to building a constant stress accelerated life test (CSALT) design is to specify the acceleration model.

Plan Factors

The Plan Factors section lists the factors and settings. To update, make changes in the Factors section and create another plan.

Plan Model

There are three sets of values to set to specify your acceleration model.

Distribution Choice

Specifies the distribution for the response. The available distributions are Lognormal and Weibull.

Acceleration Model Settings

Contains the following settings:

Specify failure quantile estimates

Use the table to specify estimates for the time until a failure probability for combinations of the accelerating factors. The estimates can be set by entering values in the text boxes or by dragging the handles on the curves in the probability by time plot.

Sigma

(Available only when the response distribution is set to Lognormal.) Specifies the assumed shape parameter for the lognormal distribution.

Weibull beta

(Available only when the response distribution is set to Weibull.) Specifies the assumed shape parameter for the Weibull distribution.

Other Specifications

Contains the following specifications:

Optimality Criterion

Specifies the criterion used to optimize the test plan. The available criterion values are Quantile or Failure Probability.

Probability of Interest

(Available only for quantile optimality.) Specifies the failure fraction for which you want an estimate of time. For example, if you want to estimate the time at which 10% of the units fail, then enter 0.10.

Time of Interest

(Available only for failure probability optimality.) Specifies the time for which you want an estimate of the failure probability.

Number of units under test

Specifies the number of units in the experiment.

Length of test

Specifies the length of time during which units are under test.

Make Test Plans

Opens a tab with test plans for the specified plan settings. Change specifications to create alternative plans. Each set of test plans opens in a tab. Double-click a tab title to rename the tab.

Want more information? Have questions? Get answers in the JMP User Community (community.jmp.com).