Numerical Simulation Research And Software Development Of Drawbeads In Sheet Forming

Computer Aided Engineering(CAE)technology is the core analysis technology of advanced manufacturing.It is the key for domestic manufacturing to improve product quality,improve mold design,and break away from empirical design.In order to break the monopoly of foreign sheet forming CAE software,independent research and development of sheet forming software is of great significance.Based on the nonlinear finite element theory of sheet forming and the calculation method of equivalent drawbeads,this paper uses C++ language to develop a numerical simulation software for drawbeads in sheet forming with adaptive mesh coarsening function.The specific work results are as follows:(1)A high-precision mathematical simulation model of rectangular and semicircular equivalent drawbeads has been established.Using the elastoplastic constitutive relationship and plane strain assumptions,the sheet is processed in layers along the thickness direction.At the same time,according to the principle of constant sheet volume,the effective radius and thickness of the strain neutral layer in the bending stage of the sheet are updated,and the Bauschinger is derived.The equivalent analysis model of rectangular drawbead and semicircular drawbead under effect,and the program of this model was compiled;the classic Nine semicircular drawbead test and B.D.Carleer semicircular and rectangular drawbead The test values of the test are used as a comparison.The errors of the drawing resistance values calculated by the model are all within 10%,which verifies the accuracy of the equivalent drawbead mathematical model.Taking the simulation of the equivalent drawbead of the air-conditioning cover plate forming part as an example,through the comparison and analysis of the Forming Limit Diagram(FLD)forming limit diagram before and after the drawbead is set,the change in the state of the sheet metal and the thickness change trend of the thickness distribution cloud map are shown The effectiveness of the rib model applied to actual engineering problems.(2)Based on the quadtree mesh refinement method,an h shaped mesh coarsening algorithm for sheet forming simulation is established.In order to take into account the calculation accuracy and efficiency of the numerical simulation of sheet forming,based on the balanced quadtree mesh refinement method,combined with the h-shaped mesh adaptive algorithm,a net suitable for the quadrilateral BT element in the numerical simulation of sheet forming is established.Grid adaptive coarsening algorithm.The algorithm follows the 1-irregular partition when processing the grid.Taking the real drawbead simulation of square box and automobile B-pillar forming as an example,it is proved that the algorithm can guarantee the mesh quality and calculation efficiency.(3)Developed a numerical simulation software for drawbeads in sheet forming with adaptive mesh coarsening function.Formulate the development process of drawbead numerical simulation software in sheet forming,and set the interface of drawbead numerical simulation software in sheet forming to module selection interface,sheet material parameter interface,process interface,equivalent drawbead interface,and solution interface.The h-shaped adaptive mesh coarsening algorithm established is placed in the solution interface.