外文翻译--板料成形中有限元仿真及相关技术的研究进展(编辑修改稿)

外文翻译--板料成形中有限元仿真及相关技术的研究进展(编辑修改稿)内容摘要：

ent of this endeavor is focused on the reduction of the tooling costs and the leadtime related to the stamping of auto body panels, even under increasing technological difficulties such as the use of aluminum alloys and highstrength steels, and requirements for higher geometrical accuracy of stamped parts. To deal with the problems brought about by these trends, which are beyond past experience, numerical methods for sheet forming simulation bee more and more important, replacing the physical tryout of stamping dies by a puter tryout. The success of numerical simulation depends mainly on the advances in forming simulation codes, but progress in other related technologies is also important. Examples of related technology are the CAD systems that rapidly construct and modify tool surfaces, modern mesh generators to, more or less automatically, create Famishes CAD surfaces, visualization hardware and software, which enables users to grasp the huge data, and, finally, the puter hardware, which makes it possible to perform large scale simulations within reasonable time. The objective of the paper is to present an overview of the current state of sheet metal forming simulation and related technologies realized in industries, and to suggest the future directions of research. Many international conferences have been held and numerous papers are published related to sheet metal forming simulation in the 1980’and 1990’. However, the information obtained through these events is not sufficient to address the above issues. For this reason the authors decided to visit automotive industries and sheet steel suppliers in Europe, Japan and the United States to discuss these specific topics with engineers and researchers working at die shops and in sheet stamping sections of industries. 2. HISTORICAL BACKGROUND Analytical study of sheet metal forming process was already started in the middle of this century [1, 2] and numerical procedures (finite difference methods) were applied to analyze ax symmetric drawing process in the 1960’ [3].Although such work contributed greatly to develop the theory of sheet metal forming analysis, this kind of approach could not be applicable to the actual production parts. Nonlinear finite element methods opened the path for the simulation of real industrial stamping processes [46]. A symposium on puter modeling of sheet metal forming process was held in Ann Arbor, Michigan in 1985 [7], in which three dimensional autobody panel forming processes are modeled by elasticplastic finite element methods using shell elements[89]. In these studies drawing process of a lift window outer and binder wrapping process of a decklid were simulated, but they were in the stage of testing and evaluation, since finite element. Simulation was still an extremely time consuming and unreliable tool to the engineer in the press shop. So that, in this symposium, geometric modeling methods [1012] and simplified mechanical modeling methods [1314] were much more appreciated by participants from industries. In NUMIFORM39。 9[15], numerous papers concerning the sheet forming simulation were presented, and among them two important directions were suggested which brought sheet forming simulation to a new horizon。 one was the application of a dynamic explicit code[16] and the other was the proposal of the one step method. In[16]Honaker and Madison demonstrated the deep drawing of an oilpan and a radiator part by using DYNA3D,obtaining deeply drawn shapes including wrinkle on the flange, which was not possible by using the static implicit code ABAQUS. After this conference several dynamic explicit codes specialized to the sheet forming simulation, such as PAMSTAMP and OPTRIS, were developed, and many automotive industries started to try these codes. On the other hand the one step method proposed by Batiste al. was developed based on idea of Chang and Lee, in which a single large time step was used, deforming the sheet inversely from the final part configuration to the initial blank configuration. A major advantage of this method is the very short putation time, and thus, based on this strategy, many codes have been developed mainly in Europe. These are ISOPUNCH, SIMEX, and FAS。