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

where:

• 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.

Solution:

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

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

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

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.

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