Research On One-step Inverse Isogeometric Analysis Initial Guess Solution Of Automobile Panel

Sheet metal stamping is usually used in the manufacture of automobile panel.For most of the complex automotive panel,the size of the blank largely affects the final cost and quality of the components.In the early stage of production activities,technicians usually relied on personal experience and trial and error methods to determine the size of the stamping blank,but the experience was often not accurate,for some parts with complex spatial configuration,these methods can not get good results.With the continuous development of finite element method,computer technology and the research method of metal sheet stamping,the finite element numerical simulation analysis method provides solutions to predict the size of stamping blank.The design of the stamping blank size belongs to the early stage of product development,it needs fast iteration,therefore,in the industrial stamping production,one-step inverse forming finite element method is usually used to indicate the blank size.At this stage,some scholars combined isogeometric analysis and incremental method in the field of stamping,and achieved good results.However,the incremental method needs to consider all aspects in the stamping process,the analysis process is complex and time-consuming,and it's not suitable for the early stage of product development.The combination of isogeometric analysis and one-step inverse forming finite element method based on full-scale method can solve the above problems.In one step inverse forming finite element method,The acquisition of the initial solution has a crucial effect on the computational efficiency,stability and convergence of the solver,therefore,the initial field prediction based on isogeometric is one of the key issues that need to be addressed firstly to solve the related problems.In view of this problem,this paper has carried out the following research work:Based on NURBS theory and isogeometric analysis,the development of isogeometric analysis membrane element,plate element and thin shell element is given,and numerical examples which have finished are given.The numerical examples show that the isogeometric analysis element has higher accuracy and efficiency than the traditional finite element method.The method of quasi-conforming triangular membrane element,quasi-conforming RF(Rotation-Free)triangular plate element,quasi-conforming quadrilateral membrane element is given.Based on the partitioned "cutting-sewing" initial field prediction algorithm,the quasi-conforming element is considered.In this paper,starting from the NURBS control point grid of the final configuration of the stamping parts,an algorithm for the initial field prediction of isogeometric analysis based on quasi-conforming element is proposed.The relevant examples show that,compared with the finite element method starting from the grid,the method is efficient and versatile,which can effectively solve the problem of the initial solution in the one-step inverse forming isogeometric analysis of complex stamping parts,which lay a solid foundation for the research of one-step inverse forming algorithm based on isogeometric analysis.