Random Reliability Analysis Based On Fuzzy Theory

Quite great progress in mechanical fuzzy reliability theory and its application have been made since the eighties of the twentieth century, but the meanings of some important concepts in fuzzy reliability theory are not accepted by all of people. Although some correlative theory have been proposed, most of these theory are obscure, and the expressions are complex, so they are difficult to put into practice. A new method of calculation of the reliability with theoretical and practical value was provided by this paper.The basic principles of reliability analysis by random fuzzy theory of this paper is put random variables into a fuzzy variable and use the concept of fuzzy math cut sets put the fuzzy variables into a uniform distribution of interval numbers and then reliability analysis. First of all, this paper subject to two random variables are uniformly distributed the difference between random variables and their joint probability density function. Its purpose is to facilitate the use of fuzzy theory to reliability analysis ,finally, reliability analysis.Secondly, in this paper the fuzzy variables and random variables on the basis of mutual transformation derivation of linear distribution of random variables with the parabolic distribution of the fuzzy variables can be mutually converted with equivalence relation.Finally, the Stress and the intensity are supposed to be fuzzy variables and then discussed calculated reliability in detail. In this paper, three methods are used to calculate the reliability.Through the calculations show that the first method has largest error and the second method has larger error and the third method has the same calculation results with stress-strength interference model. So this approach is feasible in theory.