The reliability calculation/prediction is usually the third stage (after Project Creation and Product Tree Building ) in RAM Commander Reliability, Availability, Maintainability and Safety analysis process. Create the project and build the product tree before you may proceed with the procedures explained in this chapter.

 

During this stage user should obtain failure rate for components in the product tree. RAM Commander will then calculate the sum of component failure rates to calculate the FR of assemblies, subsystems, systems and of the whole product:

 

RAM Commander may perform the reliability prediction for both Operating and Non-Operating modes.

 

There is a number of ways to calculate components Failure Rate:

1. Performing reliability prediction using one from more than 30 reliability prediction methods (such as MIL-HDBK-217, Telcordia, Siemens, FIDES, NPRD-95 etc.)

2. Specifying (manually or importing) fixed Failure Rate received from manufacturer or from field use failure statistics.

3. Specifying known Failure Rates for known temperatures and environments (using the GPRD library)

4. Allocating failure rates from assemblies down to the components (assign a required FR to an assembly and have RAM Commander allocate the required FR to each of its children)

 

Each way has its own advantages and disadvantages and is appropriate in particular conditions.