Prediction Algorithm For Initial Field Of Sheet Metal In One-step Reverse Forming Based On Isogeometric Analysis

In the early stage of the design of parts,the determination of the size and shape of stamping blanks is an extremely crucial technology.In the early production,engineers usually use the trial and error method based on personal experience to get the size of the blank,but for the complex parts of the structure,the requirements for engineers are very high and they often do not be satisfied with the blank size.With the rapid development of computer technology and finite element method,finite element numerical simulation analysis provides an effective solution for determining the dimension of stamping blanks.In the early stages of part design,the determination of the size and shape of balk is predicted by one-step reverse forming method.The isogeometric analysis method is a new numerical simulation method developed in recent years.It has the advantages of geometric accurate description,high order continuous coordination element,high precision and so on,and has been applied in various fields.In recent years,some scholars have done some researches on the simulation of stamping process combined with geometric analysis and incremental method,and have made some progress.However,the incremental method needs to consider various factors of stamping in the analysis,which makes the analysis is complicated and it cannot be applied in the early stages of part design.The above problems can be avoided by combining the geometric analysis with the One-step inverse forming method based on deformation theory.However,for One-step reverse forming,the selection of initial solution is a key technology.The selection of the initial solution directly affects the calculation efficiency,convergence and stability in the solution process.Therefore,based on the prediction of the initial solution of One-step reverse forming of isogeometric analysis,it becomes the most important question in the analysis,and the initial solution is solved in this paper.The following research work is done:Based on the CAD date used in the isogeometric analysis,a element local coordinate system suitable for One-step inverse forming isogeometric analysis is established.The coordinate system solves the problem that the isogeometric analysis cannot directly be employed to describe the element of One-step reverse forming deformation precisely,which produces the effective date source for further work.Derivation of membrane elements suitable for geometric analysis,combined with the iso-geometric analysis and One-step inverse forming method,the algorithm of One step inverse forming initial solution based on isogeometric analysis is presented.The numerical examples show that compared with the finite element mesh method,the method has high efficiency and feasibility,it can be integrated seamlessly with CAD modeling work in the early stages of part design and can effectively solve the problem of initial solution prediction in One-step inverse forming analysis of stamped parts.It lays a solid foundation for the study of the One-step inverse shaping algorithm based on isogeometric analysis.