Tolerance Analysis Of Sheet Metal Parts Based On Finite Element Method

With the development of science and technology, People put more highlights on the requirements of the assembly tolerance analysis. more and more studies are devoted to the flexible parts’ deviation analysis as the tolerance analysis based on the rigid pipe is not that precise which often greater than the actual situation. Mostly, flexible assemblies with various parts are assembled in multiple stations. Each work station does significantly effect on the assembly quality. Therefore, controlling the assembly quality of each workstation is an important portion in flexible assembly quality control.As an influential aspect of assembly quality’s measure, assembly dimensional variation affects the performance of the products directly. Assembly deviation analysis which quantitative evaluates the quality of flexible assembly product is the most primary means of flexible assembly dimensional deviation control. What’s more, the developed Finite Element Method also provides the strong back for the flexible parts tolerance analysis. Single-station flexible parts assembly process is generally divided into positioning, clamping, connection and release. However, the dominant joining method is welding whose quality directly plays an major role on the performance of the assembly. So during the flexible tolerance analysis, spot welding heat and springback effect must be considered.In order to improve the accuracy and efficiency of simple-station assembly deviation analysis, this paper introduces a flexible parts analysis method based on the Finite Element Method, and the influence of spot welding was also included. The main contents of this paper are listed as follows:(1) Review the history and research background of spot welding deformation and the flexible tolerance analysis;(2) Refine the flexible parts’ tolerance modeling process with the combination of general assembly steps and the influencing factors of the flexible assembly variation analysis;(3) Propose the method of getting parts’ stiffness matrix,more further, to obtain clamping force with the characteristics of the flexible parts and the finite element structure analysis;(4) Conclude characteristics of flexible welding, modeling in this process in the finite element software which divides part into shell units simulates the interaction between components with contact elements, and presents deviation with displacement constraints;(5) Verify the feasibility in 3D model after defining flexible parts in the finite element modeling, thermal analysis and structural analysis...