Dormant failures and PM

[gkrasin]

I would like to modify BlockSim Example RC3 - Effect of Inspection Intervals (http://www.reliasoft.com/BlockSim/examples/rc3/index.htm) to include preventive replacement on fixed item age (e.g. 4 years). What should I do?

Thank you,
Krasin

[David]

A preventative maintenance (PM) policy can be specified on the Preventative tab of the Block Properties window after selecting the Maintenance tab on the left. Then on the right, under Preventative Maintenance Policy click on the icon to the right of the dropdown to create a new PM policy. On the Preventative Maintenance Policy window there is the Upon fixed time interval based on option. Select this option and the two options below will become enabled. One of these is Item Age. Then simply enter the interval to perform PM in the supplied text box.

I hope this helps.

[gkrasin]

That's what I am doing. Nothing changes in the results. Could you attach the example file with necessary changes?

[David]

I am not sure what diagram you are working with, so I just modified the 3 Year diagram and added a PM at 4 years. The new diagram is PM 4 Year. I also added a Fixed Duration greater than zero for each applied maintenance policy so that they could be more easily tracked. By default the durations were set to zero. See attached zip file. I removed the other diagrams and policies to keep the file small.

I hope this helps.

[gkrasin]

Thank you David, I'll study this example in details.
Krasin

[gkrasin]

The problem appears if I have IN and PM at the same time. I modified the 1 Year diagram and added a PM at 4 years. Fixed Duration is zero. If inspection interval is 0.999 everything is ok, but if it is 1, than I have the same results in both cases, with and without PM. Is the problem in my computer/installation? Modified file and diagrams are here (https://docs.google.com/leaf?id=0B6CQeWVsZdSzZTk5MWI5NmItNDlhMC00YzVkLWI2N GMtZjY3NzZiYmRkM2Jm&hl=en).

[David]

In the case of simultaneous events, only one event is executed. In this case the inspection and PM are set to occur at the same time. The following order of precedence is used: inspection, PM, CM. Therefore, since the inspection has higher precedence, it gets executed while the PM does not. This is the reason why the results do not change when adding the PM at the same time as the inspection.

I hope this helps.