The Reliability Analysis And Optimal Design Of Metal Structure Based On Stochastic Finite Element Method

As the construction of machinery products is becoming more complex and the work environment is changing worse to meet the growing demand from society, so the traditional safety factor design cannot meet the need in engineering. The modern probability of reliability design based on the probability theory and mathematical statistics becomes the trend of development. For complex structures, the structural optimum design based on the reliability would be more economical, reliable and rational.Firstly, the dissertation introduced the reliability theory of the current situation and the past at home and abroad, the existing problem and the basic content of the probability of reliability design after reading a lot of documents, then briefly provided information of the basis method of probability of reliability design, included random sampling method, analytic method, mixing method and SFEM. Put forward the way of combining SFEM Monte-Carlo method and ANSYS to calculate mechanical structural reliability.Secondly, we created the FEM model of gantry crane by a parameterization method(APDL), and analyzed the mechanical properties. Calculated reliability of the whole structure with the data after 500 circular sampling by LHS Monte-Carlo method.At last, this dissertation studied the result of sensitivity analysis and inverse probability analysis, found key variables act on mechanical properties of the objective component. Optimized the less reliable component by the way of optimum design based on the reliability, putting the reliability target and mechanical properties as constraint conditions, using ANSYS as analyzing tool, though 20 loop iterations calculating of first order reliability method. Reduced the structure weight by selecting a reasonable section size of the objective component with a higher economic benefit as a result.This dissertation also introduced the progress and means of reliability growth through the whole lifecycle of mechanical structure. From the analysis of this dissertation, we could see that this structural optimum design of mechanical structure based on the reliability would be widely applied to the engineering practice in the future through some improvements.