Research On The Fuzzy Reliability Optimization Design Of Mechanical System

With the scientific and technological development, Reliability engineering is increasingly being valued by the world. The reliability of products directly affect the function of products, thus affecting the competitiveness of products. Efforts to improve product reliability, can effectively prevent frequent breakdowns and accidents, especially the catastrophic accident occurred, also avoid the frequent development of products, "after change" phenomenon, the maintaining expense is saved and the developing perid is shortened for raising product's reliability, the failure rate of product is decreased and the competitiveness of product is improved.With the deepening of the reliability of the study, people found many practical engineering problems not only exist random factors, are also widely exist in fuzzy factor, the reliability of the fuzzy theory is introduced, with the fuzzy reliability of research methods to solve the problem is the current engineering practice requirements. Mechanical design of fuzzy reliability optimization is involved in mechanical engineering in the process of optimization problems that exist in the fuzzy factor is optimized.In this paper, the reliability of mechanical system analysis, fuzzy theory is combined with fault tree, fuzzy fault tree analysis of the whole process is proposed,and combining the fuzzy comprehensive evaluation with FMECA, the failure mode and effects fuzzy analysis is proposed.Fuzzy reliability method based on reliability theory and fuzzy math is applied to optimization design of mechanical structure and part. Main jobs are done, establishing the mathematic model of practical problem,regarding the reliability and other constraints as fuzzy factor, transforming these special constraints into ordinary ones and then solving ordinary optimization design by Genetic Algorithm Optimization Toolbox in Matlab Optimization Toolbox, obtaining the optimal design.In addition, predicting the reliability of the design of the mechanical system is also a method of the reliability analysis. In the reliability analysis model, considering loading, material strength, scantlings, boundary condition and processing tolerances, and other basic variables are influned by measurements errors and other random factors. Probability finite element method were used. ANSYS parametric design language is used to model and mesh the part, and then the Monte Carlo method is used for reliability analysis, reliability analysis files is generated.