Name four distinct items that would be on a system life-cycle reliability review checklist
- Are reliability requirements properly defined?
- Are the reliability requirements realistic and compatible with other requirements?
- Has the complexity been minimized?
- Have the failure modes and effects been identified?
- Rest of them
- System life-cycle reliability review checklist:
- 1. Were the reliability requirements properly defined at the beginning of
- the project in the conceptual design phase?
- 2. Have the requirements established in the conceptual design phase been
- properly allocated down to the sub-system level?
- 3. Are the reliability requirements realistic and compatible with other
- system requirements?
- 4. Has system design complexity been minimized?
- 5. Have system failure modes and effects been identified?
- 6. Are system, subsystem, unit, and component-part failure rates known?
- 7. Are the failure characteristics (i.e. physics of failure) known for each
- applicable component part?
- 8. Has the system or product wear-out period been identified?
- 9. Have the component parts with excessive failure rates been identified?
- 10. Have fail safe characteristics been incorporated where applicable
What is reliability?
- – the probability that the system will perform in a
- the satisfactory manner for a given period when used under specified operating conditions
- Elements of reliability include:
- • Probability of failure
- • Satisfactory performance
- • Time
- • Specified operating conditions
Name the two reliability methods analyzed. Briefly describe
- Reliability prediction
Name the four reliability prediction techniques
- Prediction may be based on the analysis of similar equipment
- New equipment reliability similar to one used
- Prediction may be based on an estimate of active element groups (AEG)
- An AEG is the smallest functional building block that controls or converts energy.
- An AEG includes one active element (transducer, transistor, pump, etc…) and a number of passive elements.
- By counting the number of AEGs and considering their complexity one can predict the reliability of a system
- Prediction may be accomplished from an equipment parts count
- Design parts are listed and categorized according to their tendency to fail
- Failure rates are assigned and combined to predict the MTBF for the system
- Prediction may be based on a stress analysis
- Stresses on components can be analyzes