Windchill Risk and Reliability Desktop Help > Windchill Weibull > LDA (Life Data Analysis) > Life Data Set How-Tos > Using the Optimal Replacement Wizard
Using the Optimal Replacement Wizard
When a Weibull parametric life data set or a reliability growth data set is selected, you can use the Optimal Replacement Wizard to analyze the maintenance policy for a component based on collected failure data. You cannot use this Wizard when any type of data set for the ALT module is selected in the LDA Navigator.
The objective of optimal component replacement is to identify a replacement interval given a system goal. The goal can be either to minimize the overall cost of the system over the long term or to minimize the system downtime (unavailability).
1. In the LDA Navigator, select a Weibull parametric life data set or a reliability growth data set.
2. Select Weibull > Optimal Replacement Wizard. If the active data set is not a parametric life data set or a reliability growth data set, this command is unavailable.
The Optimal Replacement Wizard starts and displays the Distribution page. The default is the distribution selected for that data set.
3. Select the distribution to use and click Next. The Parameters page appears. The parameters required are those for the distribution you selected on the previous page. The defaults are the last values calculated for the data set.
4. Enter appropriate parameter values and click Next. The Input Data page appears.
5. Complete this page, referring to the following table for option descriptions.
Parameter
Description
Replacement objective
Indicates the replacement objective. Choices are:
• Minimize cost. When selected, the objective is to minimize the overall cost of the system over the long term. Fields for entering the costs associated with planned and unplanned replacements appear beneath Cost of replacement, which is shown on the right.
• Minimize downtime. When selected, the objective is to minimize the downtime of the system (unavailability). Fields for entering the time associated with planned and unplanned replacements appear beneath Downtime of replacement, which is shown on the right.
Replacement time interval
The starting and ending points in time for the replacement interval. The default for Minimum is 0. Before you can go to the next page, you must enter a value less than the default value for Maximum. You can also enter a different starting point value for Minimum.
Replace based on
Indicates the maintenance policy to use. Choices are:
• Failure or age. When selected, components are replaced upon failure or at a predefined age.
• Failure or block of time. When selected, components are replaced upon failure or at predefined time, regardless of the age of the component or part being replaced. Maximum number of failures in replacement Interval becomes available.
For more information, see Component Replacement Policies.
Cost of replacement
When the objective is to minimize cost, Planned and Unplanned are shown under Cost of replacement so that you can specify the costs associated with planned and unplanned replacements.
Downtime of replacement
When the objective is to minimize downtime, Planned and Unplanned are shown under Downtime of replacement so that you can specify the downtime associated with planned and unplanned replacements.
Maximum number of failures in replacement interval
The maximum number of replacements that can occur due to failure in the replacement time interval. This parameter is available only if Failure or block of time is selected as the maintenance policy for Replace based on. The default is 5.
6. When finished, click Next. The Wizard Complete page appears.
7. Click Finish. Once optimal replacements are calculated, the Optimal Replacement Results window opens and displays results. For more information, see Optimal Replacement Results Window.
8. When finished viewing the information in this window, click Close to close it.
Life Data Set How-Tos