Research On 3-D Elasto-plastic FEM Numerical Simulation Of Multi-process Neck Spinning Of Tube

Multi-process conventional spinning used as a method of metal plastic forming has been widely applied in fields of aeronautics, astronautics and weaponry. However, up to now, there has been so insufficient theoretical study of the process that the selection of roller motion locus still depends on trial-and- errors. So research on the forming law of Multi-process conventional spinning is one of the important subjects in the development of spinning technology. The research is of a significant practical value for improving forming limits, part quality, processing efficiency, and developing new products. In this dissertation, using a method of computer numerical simulation combined with theoretical analysis, research on 3-D elasto-plastic FEM numerical simulation has been carried out for multi-process neck spinning, a typical method in multi-process conventional spinning. In addition, a method of determining multi-process roller motion locus has been preliminarily explored. A brief introduction to the project and its main results are as follows: A mechanical model corresponding to reality has been established for 3-D elasto-plastic FEM numerical simulation of multi-process neck spinning of tube. Key techniques of the 3-D elasto-plastic FEM numerical simulation have been studied systematically, including space inclined constraint, dynamic boundary conditions and local loading and unloading etc, and some method to effectively treat those problems have been proposed. Frontal solution used in the simulation makes it possible to solve larger elasto-plastic forming problems such as multi- process conventional spinning on a microcomputer. A 3-D simulation system?D-CSPIN based on 3-D elasto-plastic FEM oriented to multi-process neck spinning of tube has been developed in the dissertation by using a modular approach which has a friendly function in pre- treatment and post-treatment and can be easily extended and expanded. The system can also be popularized to other finite element analysis of metal plastic forming with local loading and unloading problems. The eight-node hexahedron isoparametric element is used to mesh the ?The project is supported by the Foundation of National Key Laboratory of Defense Science and Technology for Precision Hot Processing of Metals of China (grant No 98JS61 .2.1 .HKO3 14)and the Aeronautical Science Foundation of China(grant No 00H53075). ?II ? whole deforming body into 2160 nodes and 1512 elements. By using the 3D- CSPIN system for simulation of multi-process conventional spinning, the stress and strain of deforming zone has been obtained, furthermore, the stress and strain distribution law has been revealed, which shows the characteristic of local loading and plastic deforming. How to determine reasonable multi-process roller motion locus has been preliminarily explored and a method proposed is the following. Establishing a work platform based on the 3D-MSPI7N system, computer simulation is used as a principal technical means to carry out determining multi-process roller motion locus, which makes clear the direction of further study for the roller motion locus.