Reliability Elements: Internally Handled Actions

This is a simple model of a car starter that uses internal actions. The car is started three times per day, and the starter requires the battery, and the starter solenoid and motor to be operable. When the starter's action is triggered, GoldSim triggers the Actions of components within the starter to determine whether the car was able to start successfully.

While the battery and components of the starter can fail, obviously leading to failure of the action each time it is triggered, the child Action elements in this model make use of the Unreliable failure mode. Unlike other failure modes, this does not actually cause components to fail in the sense that they need to be repaired, but rather causes a proportion of triggered actions to fail.

We can see the number of actions that fail by subtracting the number of actions successfully completed by the starter from the total number of times its action was triggered.

If you view the time history, it is apparent that failures begin to occur after about 2 years. While some fail completely early on, many simply experience a handful of failures due to the unreliable failure mode. This can be seen by viewing the time histories for individual realizations. Standard causal analysis and reliability values are available for the starter. However, it is important to note that failure to complete a triggered action has no bearing on the reliability of a component. You'll notice that all of the realizations, even where the component does not fail, have a handful of failed actions (caused by the unreliable failure mode), but the Starter still has a reliability of approximately 60% over five years.

To Open the Model File:

1. Start GoldSim
2. Click on the File and select Open Example...
3. Browse to Reliability Examples
4. Select the file called InternallyHandledAction.gsm