Research On The Combination Algorithm Of Multiple Failure Domains For Reliability

Reliability is an important index to measure the quality of products, so obtaining the higher accurate reliability is great significance to improve the quality of products. According to the approximation ideas of FORM and SORM, the paper presents a calculation method based on minimum cut set, in order to improve the calculation accuracy of reliability in the complex state function failure.For the implementation of this method, the paper carried out a series of detailed research work. The paper detailedly introduced the development of the approximate algorithms of reliability, as the research work has been clear about the direction. The basic train of thought and computing results about FORM and SORM reveals the deficiency of these methods, and the paper detailed studies the two important parameters in the reliability analysis:the main curvature and the reliability index. The scope of FORM and the SORM were expanded, through the reasonable rules of main curvature and the reliability index were used. In the provisions of the principal curvature and the reliability index, the quadratic state function was transform into the linear state function on the basis of using the reliability index obtained by SORM. The paper will redefine the main curvature and the reliability index is introduced into two dimensional standard normal distribution function approximation algorithm, and realizes the two linear state function failure domains of overlap more accurate calculation of probability, basing on the combination of the intersection relations. Applied the minimum cut set to reliability calculation, the combination of multiple failure domains was turned into the combination of multiple minimum cut sets, and then the probability of this combination was turned into the algebraic addition of the probabilities on the intersections of multiple failure domains, the transformation and calculation of the minimum cut sets was realized. The predecessors’ research of the calculation method on the failure domains intersection of three linear state functions for failure probability is introduced into the probability calculation of the failure domains intersection of multiple linear state functions, and probability calculation on the intersection of multiple failure domains was accomplished, thus to ensure the successful implementation of the method in the paper.These examples and analysis not only proved that the method presented in this paper is feasible, but also pointed out that choosing the appropriate calculation failure domain is the key to improve the calculation precision of the method.