A Decreasing Failure Rate, Mixed Exponential Model Applied to Reliability

摘要

Decreasing failure rates for electronic equipment used on the Polaris, Posiedon and Trident missile systems have been observed. The mixed exponential distribution has been shown to fit the life data for the electronic equipment on these systems. This paper discusses some of the estimation problems which occur with the decreasing failure rate mixed exponential distribution when the test data is censored and only a few failures are observed. For these cases sufficient conditions are obtained that maximum likelihood estimators of the shape and scale parameters for the distribution exist. Actual data, obtained from the testing of missile electronic packages, are provided to illustrate these concepts and verify the applicability and usefulness of the techniques described. (Author)