The Structure Reliability Analysis Of Aluminum-alloy Car Body Based On Finite Element Method

At present, China’s high-speed rail is in a period of rapid development. The high-speed EMU has been large studied and the noteworthy results are made. However, the design of the aluminum-alloy car body is still only calculated static strength and modal, and the concept of reliability is still ignored. Therefore, this paper aims to explore a static strength reliability analysis method of the large and complex structure like aluminum-alloy car body.Firstly, the common reliability analysis methods are introduced, and their respective advantages and disadvantages and applicable scope are summarized. Based on the characteristics of the aluminum-alloy car body, the reliability analysis method and process are proposed.Then, through further research of ANSYS PDS module, this paper studies on the ways and methods of aluminum-alloy car body reliability analysis. Among, the main point is fitting the response surface equation based on the ANSYS FEA results. For the response surface analysis, ANSYS provides two sampling methods:Central Composite Design and Box-Behnken Matrix. The two methods make a significant reduction in the number of sample points. So, this is a most efficient way for the reliability analysis of the large and complex structure like aluminum-alloy car body.Finally, through the calculation of the TC-02aluminum-alloy-car body, this paper verifies and optimizes the proposed method and process, and summarizes a set of easy-engineering applications and high accuracy reliability analysis method of aluminum-alloy car body:1. Analysis of aluminum-alloy car body structure, then simplify and mesh it;2. Determine the random variables and distribution;3. Choose the response surface analysis sampling method, and FEA calculation;4. Fit the response surface based on the ANSYS FEA results;5. Calculate the reliability using the MC simulation or the FOSM check dot method;6. Analyze the sensitivities by ANSYS PDS.From the TC-02four conditions results, although with a certain safety factor, the structure still exist the possibility of failure. The compressive condition is more dangerous, and the reliability is70%to80%. Therefore, only static strength check is not enough, the reliability analysis should be combined with it.