Weibull++ Equation Fit Solver Example

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Weibull++ Equation Fit Solver Example

The Equation Fit Solver can be used to perform linear and nonlinear regression. For example, assume that an engineer collected the following degradation data.

Time Reading
5 8.08
10 13.52
15 21.86
20 31.96
25 37.86
30 46.67
35 53.35
40 62.29
45 71.62
50 80.37
55 91.43
60 104.00

From the physical mechanism, the engineer knows that the degradation path follows the following equation:

[math]y=a+bx+c\ln (x)[/math]


  • x is the time
  • y is the degradation reading.

This model is not a standard degradation model in Weibull++; however, the problem can be solved by using the Equation Fit Solver.


Step 1: Insert an Equation Fit Solver folio in your project and enter the given data in the folio, as shown next.

Equation Fit Solver Data.png

Step 2: Enter the degradation equation in the control panel and name it “My Degradation Equation,” as shown next.

Equation Fit Solver Function.png

Step 3: Click Calculate. The following picture shows the results.

Equation Fit Solver Result.png

Step 4: You can use the Calculate Y given X area on the control panel to make predictions. For example, the predicted Y value at X=100 is 176.2424.

Equation Fit Solver Prediction.png

Step 5: The following plot shows the fitted model and the observed values.

Equation Fit Solver Plot.png