Reliability Growth Projections and Management - Only in RGA!
An effective reliability growth test planning and management strategy can contribute greatly to your ability to meet desired reliability goals on time and within the project budget. RGA provides exclusive support for several innovative reliability growth projections and planning methods based on the Crow Extended and Crow Extended – Continuous Evaluation models.
Failure Mode Classifications and Effectiveness Factors
Although traditional reliability growth analysis requires the assumption that all design improvements are incorporated before the end of the test (test-fix-test), many real-world testing scenarios may also include some failure modes that are not fixed, and others where some or all of the fixes are delayed until a later time (test-fix-find-test or test-find-test). With the Crow Extended and Crow Extended – Continuous Evaluation models, you can use Failure Mode Classifications to provide the appropriate analysis treatment for any of these management strategies.
- A indicates that no fix will be applied (i.e., management chooses not to address the failure mode because of technical, financial or other reasons).
- BC indicates that a fix was applied at any time during the test (Crow Extended) or immediately after the failure and before testing continues (Crow Extended – Continuous Evaluation).
- BD indicates that the fix will be delayed until after the completion of the test (Crow Extended) or until some later time during testing or after the last test phase (Crow Extended – Continuous Evaluation).
For delayed fixes, both models use Effectiveness Factors to indicate how much the failure intensity of each mode will be reduced once the fix has been implemented (e.g., EF=.7 indicates that 70% of the failure intensity from the mode is expected to be removed while 30% will remain).
Growth Planning Metrics and Projections
Analysis with either of the Crow Extended models makes it possible to calculate and plot some additional metrics that are useful for managing your reliability testing program.
- Projected MTBF (or Failure Intensity) - the reliability that will be achieved after delayed fixes have been implemented.
- Growth Potential MTBF (or Failure Intensity) - the best reliability that could be achieved by applying the current reliability growth management strategy. If this metric indicates that your goal cannot be achieved with the current level of testing and fixing, you may be able to adjust the strategy.
- MTBF BD Unseen - the rate at which new unique BD failure modes are being discovered at any given time.
- Cumulative Number of BD Modes - the total number of unique observed BD failure modes at any given time.