Numerical Simulation and Analysis of Sheet Metal Based on Single-point Increnmental Forming

Abstract: Incremental forming is a new sheet forming technology which introduces Layered Manufacture (LM) method into the sheet metal processing, using a special forming tool processes sheet metal layer by layer along the programmed trajectory with the increments of continuous local plastic forming, so expected parts with complicated shape are formed. The whole process is easy automatization from modeling to CAE analysis and to machining contour.The SPIF (single-point incremental forming) process presents nonlinear on geometry、material and state, the boundary condition is also discontinuous, so the forming mechanism is complicated. At present, the technology is still in the laboratory stage, the study of the technology is not deep enough, and there isn't systematic theories system to support it. In order to reduce the times of the experiment and put the technology into practice as soon as possible, it is a good idea that the whole forming process can be simulated and the keys can be acquired by numerical simulation method.Firstly, the paper introduces the forming principle and characteristics and analyses the forming mechanism of the SPIF, analyses stress、strain states using slab method, discusses the design principle of formig traiectory and thickness distribution law of sheet. Secondly, the paper builts FEM models according to the forming principle of SPIF、based on software-ANSYS/LS-DYNA, describes in detail selection principles of various technological parameters in the whole simulation process.At last, the finite element simulation method is proposed. Finally, the influence of the different part size to thickness variation of main deformation area and the influence of the different forming angles to forming quality are researched by the simulation of square pyramids and a face-part. By the simulation results compared with the experiment measured value, it is proved that using the FEM to simulate the SPIF process is available. The finite element simulation method proposed by the paper may instruct the actual processing of incremental forming to obtain the optimal process parameters, the method has certain theory significance and engineering value…
Key words: Sheet metal incremental forming; numerical simulation; forming angles; complex surface