Using Life-Stress Data Folios

Weibull++'s life-stress data folio allows you to perform quantitative accelerated life testing data analysis. In this analysis, you extrapolate a product’s failure behavior at normal conditions from life data obtained at accelerated stress levels. Since products fail more quickly at accelerated stress levels, the analysis allows you to obtain reliability information about a product (e.g., mean life, probability of failure at a specific time, etc.) in a shorter time.

The basic steps for using a life-stress data folio are:

1. Add life-stress data folio

Right-click the Life-Stress Data folder in the current project explorer and choose Add Life-Stress Data.



In the setup window, select the desired censoring type and units for time/usage values (hours, cycles, etc.). (See Accelerated Life Testing Life-Stress Data Folio Setup.)



On the next page, define the stress type(s) to use in the analysis and the use stress level.



2. Enter data

Enter the data and use the control panel to specify the life-stress model. (See Life-Stress Data Folio Control Panel for available models.)



3. Analyze data

Click the Calculate icon on the control panel.



The Analysis Summary area displays the parameters of the distribution. Click the Detailed Summary icon to view more information.



4. View plots

Click the Plot icon on the control panel to open the plot sheet. (See Accelerated Life Testing Plots for available plot types.)



To show the confidence bounds, click the Confidence Bounds link on the plot's control panel, and then set the desired type of bounds and confidence level.



5. Calculate metrics

Click the QCP icon on the control panel to open the Quick Calculation Pad.  (See QCP Calculations for Accelerated Life Testing Analysis for available calculations.)



The following example shows the estimates for reliability and the lower one-sided 90% confidence bound.