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Weibull analysis

Main Help

Reliability
Weibull analysis
- Suspensions
- Diff failures modes
Weibayes


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Select Weibull in statistical mode 5. to use the Weibull reliability mode.


For calculating the Weibull properties of a data set the data must entered in the input table 1. The result will be displayed in the result array 3. and the weibull graph will be plotted 9.


Suspensions

Suspensions for not failed units or fail by different failure mode, can be set by right clicking on these cells. The suspended units will be marked gray in the input table 1.

More about what the influence of suspensions on the Weibull curve are.

Warning!

The calculations of the selection boxes 8. (Mean, STDEV etc.) are affected by the suspensions!

Confidence level

Upper lower or both can be set in the statistical mode plane 5. The level can be set in the same plane.

Raw data

To see the actual data from the Weibull graph Select graph in the statistical mode plane 5.

To see the data from the upper lower or mean change the check box upper left of the raw data table.

Formula

Calculation of the Y-axle (Median rank)

No suspensions

formula

In case of suspensions

formula

formula

Regression for β and η

formula

formula

formula

formula

Correlation coefficient

formula

Confidence interval (beta-Binominal)

formula

Legend

η (eta) = Characteristic life (63.2% of the samples will have failed)
β (beta) = slope of the weibull plot
n = amount of samples the units in test

Example


Data