Failure Rate
When you select Failure Rate for Failure Method in the Prediction Data pane for a user-defined part, Failure Rate is typically the only parameter available. In it, you enter a failure rate for the part. If you leave this field blank, the failure rate used for this part is the one specified in the User-Defined Categories pane in the Common Library.
Any failure rate that you enter is assumed to be constant. This means that there are no dependencies on temperatures, environments, or other variables. The unit for all failure rates that you enter is specified by Failure Rate Multiplier, which appears under General in the System file properties. For more information, see General System File Properties.
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When the Telcordia Issue 2, Telcordia Issue 3, and Telcordia Issue 4 models are selected, Standard Deviation is also shown in the Prediction Data pane for the user-defined part. If you have a standard deviation you want to use with the failure rate specified for the user-defined part, you enter it here.
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To use the default failure rate for the part, you do not need to do anything. Any time that Failure Rate displays #.# signs when calculations run, the failure rate used for this part is the one specified in the User-Defined Categories pane in the Common Library. To view this default value, click Defaults. The default value appears in a bold font. If you want to save this value as the failure rate for the part, leave the default values displayed. Otherwise, click Defaults again to hide this default value. If the default value is visible when you move off the Prediction Data pane, it is saved to the record. When you return to this pane, this value would no longer appear in a bold font because it would now be an entered value.
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Even if the default value is not left displayed so that it is saved with the part, it is still used during calculations if Failure Rate displays #.# signs when calculations are run. An exception occurs when a failure rate is entered for Failure rate, specified in the General Data pane for the part. Any specified failure rate in the General data pane for a part supersedes any entered value or default value in the Prediction Data pane. Similarly, any failure rate entered in the Calculation Data pane for an assembly supersedes any calculated failure rate for that assembly. For more information, see Failure Rate Types for Assemblies and Parts.
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If the default value is 0.00000, no failure rate has been specified for this user-defined part in the Common Library. Default failure rates for user-defined parts are specified on the User-Defined Categories pane in the Common Library. You should periodically open this special Project to ensure that default failure rates are entered for all user-defined parts.