Springback of sheet metal induced by elastic recovery is one of major defects in sheet metal forming processed. Springback is influenced by many factors including properties of the sheet material and processing conditions. In this paper, springback simulation is conducted and comparisons between results based on different processing variables are illustrated. Furthermore, the discovery of knowledge of the effects of geometry and process parameters on springback from FEM results becomes increasingly important, as the number of numerical simulation has grown exponentially. Data mining is an effective tool to realize knowledge discovery in simulation results. In the present paper, a data-mining algorithm, rough sets theory (RST), is applied to analyze the effects of process parameters on springback in U-bending.

On the basis of the practical situation of cold forging process planning, the disadvantages of a rule-based solution are discussed, and a case-based reasoning-based cold forging process planning (CFPP) system model is proposed. Several key problems involved are analyzed, among which a feature-based part representation scheme and a two-level retrieval mechanism are introduced to solve the problems of case representation and case retrieval. It is established in this paper that case-based reasoning-based CFPP is a promising technology for both long-term research and the promotion of efficiency for current cold process planning systems. 2001 Elsevier Science B.V. All rights reserved.

A rate-inderpendent polyerystallme plasticity constitutive model considering sclf and latent hardening was develped. Next, a new orientation probabillity assignment method was proposed and the crystal orientations were assigned to FE integration points, which reprcenet crystals and can rotate individually. Then eup drwing of FCC aluninum sheet was studied usig erystalline plasticity finite fimite element analysis. The results show that the validity of proposed model is proved throuth compatison bet ween numerical results and experimental. For the roled aluminum sheetm which contains strong {001}<110> texture, caring is formed at 45

In the present paper, a 3-D rigid visco-plastic finite-element method coupled with void damage was developed for analyzing the fine-blanking process with an ineremental implicit algorithm. Based on the Gurwon Tvergaard-Needleman plastic peoteial equation and the orthogonal rules, the effect of of void volume fraction was introduced into the material constitultive law to document the ductile damage of the deformed material. A principle of variation of rigid visco-plastic material was presented considering both the shear work and the work caused by the cahange of vloume. This proposed principle revals both the effects of equivalent stress and bydrostatic pressure. The related FEM equations coupled with void damage based on this principle of ductile fracture in the blanking process. Based on the obtained system. the fine blanking process was simulated and the onset of the micro-crack of the sheet wais predicted. Furthermore, the influence of the studied work-piece shape on the deformation process was also discussed.

Based on the Curson-Tvergaard void damage plastic potential equation and by using orthogonal rules of plastic material, the influence of void volume fraction on stress and strain fields was introduced into Levy2Mises flow rules. The variation principle of rigid plastic material with void degradation was demonstrated. Furthermore, FEM equations coupled with damage factor were presented to study the void growth and the criterion to judge the damage was also given. Using the developed system, the fine blanking process was simulated and the sheared surface of the part edge was predicted. Meanwhile, the influence of process parameters, such as punch-die clearance, V-ring force, counter force, radius of punch and die edges, on the height and quality of the sheared surface was analyzed. The calculation results were compared with the experiments, which can be used to guide the design of fine2blanking process.