The Estimation And Properties Of Reliability And Mean Life For Complex System Under Constant-Stress Accelerated Life Tests

Reliability is one of the important indexes for evaluation of product quality, and the performance index of the product is one of people’s concern, so the research on the product reliability is very important. With the development of science and technology, there are more and more products with high reliability and long life. It is unable to conduct life testing to evaluate the reliability under normal conditions.Using accelerated life tests can evaluate product reliability in a short time.The method of accelerated life tests was introduced into our country since the nineteen seventies. The method was widely used in machinery, electronics instrumentation and other industries, and our country has formulated related national standards. Accelerated life tests have three main types, namely, constant-stress accelerated life tests, step-stress accelerated life tests and progressive-stress accelerated life tests.In this paper, the research problems are as follows:Firstly, this paper introduces the implementation conditions and related content of statistical inference about constant-stress accelerated life tests; this paperalso introduces the reliability of the complex system and expression of the mean life based on the description of the minimum path matrix.Secondly, under the assumption of constant-stress accelerated life tests and the knowledge about the minimum path matrix of the complex system, when the life span of each subsystem subject to the exponentialdistribution of different parameters, we can get the conclusion that the life sample of each subsystem is the censored sample. Under this condition, it comes out the estimation and the estimation’s asymptotic distribution of reliability of a complex system. And on the basis of this conclusion, this paper introduces the application of determining the lower confidence limit of the reliability of complex systems.Finally, on the basis of knowing the expression of the mean life of the complex system, combining the estimation of the mean life of the subsystem, this paper gets the estimation and the estimation’s asymptotic distribution of the mean life of complex systems under constant-stress accelerated life tests. And on the basis of this conclusion, this paper introduces the application of determining the lower confidence limit of the reliability of complex systems.