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Reliability for Failure Rates Different over Time Intervals

Failure rate serves as a pivotal role in reliability study. Of all, the constant failure rate is the most popularly used in field exercises. In reality, however, the electrical and electronic parts’ life is represented by not only the constant failure rate but the decreasing and/or increasing failure rates. Explicit consideration and incorporation of them into the model development may yield more desirable results. In this study, we built a reliability model for failure rates varying over time intervals and derived well known measures such as probability density function, reliability function, mean life, moments, and mission time. We then evaluated mean life with consideration of the first-year multiplier and compared the results those with constant failure rate. The results given in the study may provide a reference applying for practical decision making.