Research On The Theory And Application Of Adaptive Mesh Generation For Thin Metal Parts

The forming process of many thin-walled metal parts is prone to large deformation,large strain and stress concentration.The finite element method based on variational principle and partition interpolation is an important numerical method.Therefore,the density of region subdivision has an important influence on the result precision and calculation.In addition,in engineering practice,it is often necessary to modify the shape and size of components and process parameters repeatedly,and carry out multiple calculations.At this point,according to the characteristics of the structure and load,it can be simplified into a two-dimensional model for calculation,so as to preliminarily determine the optimized structure size and process parameters,and then use the threedimensional model for more accurate calculation.How to achieve higher accuracy with less computation is a hot research field in the field of numerical computation.Therefore,based on the finite element calculation software ABAQUS and the numerical calculation software MATLAB,this paper studies the adaptive mesh technology for the nonlinear forming process of thin-walled metal parts,and develops the corresponding two-dimensional adaptive finite element calculation module.The main research contents of this paper are as follows:(1)The research and improvement of error estimation theory.Three main reasons for the low precision of stress and strain in the conventional displacement finite element solution are summarized,and the research focus is placed on the theory of superconvergent posterior error,and the problems of low precision and too many sampling points in the practical application of this theory are improved.(2)The research and development of mesh refinement methods.The characteristics,advantages and disadvantages of two-dimensional triangle mesh and quadrilateral mesh refinement method are studied,and corresponding refinement program is developed.The application of different mesh refinement methods to the same example proves that the refinement methods developed in this paper have good feasibility,and determines that quadrilateral refinement is suitable for the optimal comprehensive performance of the development environment in this paper.(3)A two-dimensional adaptive finite element calculation module has been developed.Determine the basic calculation flow,module structure,sub-module data structure and so on.The module mainly includes the following parts:extraction and processing of calculation data,calculation of posterior error and cell marking,mesh refinement,and modification of inp files.The developed adaptive module is applied to the calculation of an example,which is proved to be feasible and reliable,and has a wider application area than the self-adaptive module of ABAQUS,which greatly reduces the workload and operation difficulty of conventional finite element calculation under the same mesh size.