ALT Parameters Pane for an Accelerated Degradation Data Set
When an accelerated degradation data set is selected in the LDA Navigator, you supply the parameters required for this type of analysis in the ALT Parameters pane. The following table describes all of the parameters that can appear in this pane for an accelerated degradation data set. They are basically the same parameters that appear for degradation analysis in the Weibull module with the addition of a button for specifying stress data.
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Parameter
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Description
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Model
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The model to use in the accelerated degradation analysis. Choices are Linear, Exponential, Power, Logarithmic, Gompertz, and Loyd-Lipow. These same models are used for degradation analysis in the Weibull module. For more information, see Degradation Models. You can use the Best Fit Degradation Model Analysis window to determine the best model for analyzing the data. For more information, see Finding the Best Fit Degradation Model for a Degradation Data Set.
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Critical degradation (Y)
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The value at which a unit under degradation testing is determined to have failed. This value is used to extrapolate the failure time result.
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Set suspension time
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Indicates whether to use a suspension time for calculations. When this checkbox is cleared, no suspension time is used. When it is selected, Suspension time (X) becomes available so that you can indicate the time past which no failure times should be estimated. For example, if the unit is not expected to run past a certain time, using that value as the suspension time might be beneficial. If a unit survives past this time, it has surpassed its designated useful life.
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Suspension time (X)
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This parameter is available only when Set suspension time is selected. If you specify a suspension time, exercise care. Setting the suspension time too low might result in no failure times result, rendering the analysis useless. Setting the suspension time too high might result in all failure times, making the suspensions ineffective.
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Resulting data set
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Provides for linking the calculation results for the current accelerated degradation data set to an ALT data set. Clicking this field’s browse button opens a window for selecting a life data set. This sane window is used by the Weibull module. For more information, see Life Data Set Window.
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When clicked, the Stress Model window opens so that you can view and modify the stress data for the data set. For more information, see Stress Model Window.
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