Constant Stress ALT Factors

The first step to building a constant stress accelerated life test (CSALT) design is to define one to three accelerating factors. The default CSALT design has one three-level factor.

Figure 22.3 Initial CSALT Test Plan Window 

Factor Buttons

Factor Name

Specifies the name of the factor. When a factor is added, it is given a default name of X1, X2, and so on. To change this name, click the default name and enter the desired name.

Number of Levels

Specifies the number of levels for the factor.

Factor Transformation

Specifies the life-stress relationship, which is the manner in which the life distribution changes across stress levels. The transformations available are Arrhenius, Inverse, Log, Square Root, and Linear.

Low Usage Condition

Specifies the lower bound for the factor in typical usage conditions. To change values, click the default values and enter the desired values.

High Usage Condition

Specifies the upper bound for the factor in typical usage conditions. To change values, click the default values and enter the desired values.

Note: The Low Usage Condition and High Usage Condition values can be equal. Use equal values when the usage condition is a single value.

Low Test Condition

Specifies the low test condition. To change values, click the default values and enter the desired values.

High Test Condition

Specifies the high test condition. To change values, click the default values and enter the desired values.

Note: The low and high test conditions cannot be equal. They define the endpoints of the acceleration factors in the design.

Create a Plan

Opens a tab to specify the test plan for the specified factor settings. Change factor settings and click Create a Plan to create an alternative plan. Each plan opens in a tab. Double-click a tab title to rename the tab.

Note: When design specifications result in a singular design matrix, a plan is not generated. Adjust specifications as suggested by the warning.