BlockSim Example: CM Triggered by Subsystem Down

CM triggered by subsystem down

Purposes

The purposes of this example is to illustrate how to model the case when CM is triggered by failure of subsystem.

Description

Three devices A, B and C are in parallel. A and B form a subsystem. Only both A and B fail (subsystem fails), then start to repair A and B. The repair of C is depend on its failure. When C fails, then start to repair C.

BlockSim Solution

The BlockSim modeling of this system is shown in Figure below.

Reliability of all blocks follow Weibull distribution with Beta =1.5 and Eta=500 hours.

Block A and Block B are belong to maintenance group MG_AB.

CM of Block A and B are set to "When found failed during an inspection". The CM duration is 120 hour and upon repair, they are as good as new.

There is an inspection for both block A and B. The inspection is performed based on events in maintenance group MG_AB. If "Block fails" or "Start of corrective maintenance" event occurs for any of the blocks in the maintenance group MG_AB, then the inspection is performed. The inspection duration is set to "Immediate Repair" and upon inspection, the device is restored to same as it was when it failed (as bad as old).

CM of Block C is performed upon failure of Block C and the duration is 20 hours. It is as good as new upon repair.

 Block Up/Down plot

The system event log is shown in Figure belwo and is as follows:

1. At 100, Block A fails, and activates Block AA.
2. At 110, Block AA fails, and activates Block C.
3. At 230, Block B fails, and activates Block BB.
4. At 240, Block BB fails, and activates Block A.
5. At 340, Block A fails, and activates Block AA.
6. At 350, Block AA fails, and activates Block B.
7. ...