Parametric Recurrence Data Analysis Case Study For Weibull++ 7

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Weibull++ 7 Case Studies

Case Study 9 - Parametric Recurrence Data Analysis Example

Software Used:
Weibull++ 7

Background
The repairs made to a system are tracked over a period of time. Each repair is capable of addressing any damage accumulated up to the time of the current failure. The objective is to determine how effective the repairs are.

Experiment and Data
The table below displays the failure times for the system.

0.7	121.9	285
3.7	125.5	304
13.2	133.4	315.4
15	151	317.1
17.6	163	320.6
25.3	164.7	324.5
47.5	174.5	324.9
54	177.4	342
54.5	191.6	350.2
56.4	192.7	355.2
63.6	213	364.6
72.2	244.8	364.9
99.2	249	366.3
99.6	250.8	373
100.3	260.1	379.4
102.5	263.5	389
112	273.1	394.9
112.2	274.7	395.2
120.9	282.8

Analysis
Step 1: Add a Parametric RDA Folio to an existing project by selecting Add Specialized Folio then Add Parametric RDA from the Project menu.

Step 2: Enter the data into the Data Sheet and select Type II for the virtual age either in the Settings Area of the Control Panel Main page or on the Control Panel's Analysis page. Select 3 parameters. The Folio will look like the one shown next. Note that you must enter the final observation time once as a a failure (F) and once as the end event (E).

Parametric RDA Folio Data Sheet

Step 3: Click Calculate to calculate the parameters, as shown next.

Parametric RDA Folio Data Sheet, calculated

In ReliaSoft’s BlockSim software for system reliability, maintainability and availability analysis, the restoration factor, r, can be a number from 0 to 1, where 1 indicates that the block (component) is "as good as new" after the maintenance action (i.e. with a new age of 0) and 0 indicates that the block has not been improved at all by the maintenance action (i.e. with an age the same as the age before the maintenance was performed). A restoration factor of 0.5 implies a 50% improvement to the block and sets the age of the block to 50% of the age of the block at the time of the maintenance action. A restoration factor of 0.75 implies a 75% improvement to the block and sets the age of the block to 25% of the age of the block at the time of the maintenance action.

When you are using the Type II virtual age model in Weibull++'s Parametric RDA Folio, the restoration factor is equal to 1 - the q parameter. Thus, the restoration factor here is 0.0684, which implies a 6.8% improvement to the system.