Reliability Engineering: From Failure Probability to Decisions

Reliability is probabilistic

Reliability is the probability that an item performs its function for a stated time under stated conditions.

Failure distributions

Weibull and other models describe early failures, random failures or wear-out. Parameter interpretation must match mechanism.

System architecture

Series systems are limited by the weakest element; redundancy can improve reliability but introduces complexity and common-cause risk.

Data limitations

Censored tests, small samples and changing populations can make apparently precise life estimates misleading.

Engineering takeaway

Tie statistical life models to physical failure mechanisms and the actual duty cycle.