ANALYSIS OF THE INDUSTRIAL SHEET METAL FORMING PROCESS USING THE FORMING LIMIT DIAGRAM (FLD) THROUGH COMPUTER SIMULATION AS INTEGRATED TOOL IN CAR BODY DEVELOPMENT Gleiton Luiz Damoulis Edson Gomes Gilmar Ferreira Batalha Laboratório de Engenharia de Fabricação - Escola Politécnica da Universidade de São Paulo – Depto of Mechatronics & Mechanical Systems Engineering - Av. Prof. Mello Moraes, 2231, 05508.970 - S. Paulo, SP - BRAZIL. Fone 00 55 11 30915763 - e-mail: gilmar.batalha@poli.usp.br Abstract: New market requirements have becoming more persistent through the introduction of new technologies that can lead the actual vehicle designs to reach very high safety standards, reduce of weight (improvements on fuel consumption, emissions and performance trends), world class quality levels at reasonable production costs and schedule timing for product development, due new design features and mainly the introduction of new technological materials for a so called Lightweight Car Body Concept. A new generation of simulation software’s based on explicit or implicit Finite Element Method (FEM) are becoming more affordable and are increasing their reliability in the presented results. The question is, how can these software support the process/product development engineer in the choose of the right body-in-white component design, blank and tool geometries, the right process parameters and moreover the right material choose, mainly due the market introduction of many new technological steels families for car body construction in the last years. As an example, in the car body-in-white development, the design of body panels can be supported effectively by the use of the Forming Limit Diagram (FLD), through the computer simulation of the sheet metal forming process with the FEM. This work describes how an explicit finite element program can be applied to lay out industrial deep drawing processes, accomplished by the use of the FLD methodology and the updating procedure for the model data and the computational process. The main part of the paper discusses simulation applied skills and explains in an example of industrial process how the use of the FLD can helps to improve the interpretation of the simulation and in the choice of the best steel. Keywords : sheet metal forming, forming limit diagram, computer simulation, finite element . 1. INTRODUCTION To reach the new market requirement targets for the automotive body development, process integration since the early concept development phases until the start of production, must provide a streamlined scalable environment that encompasses every step in the process from early design feasibility to the process final validation. High safety standards, the high reduction of weight that improves fuel consumption, emissions and performance trends, a world class quality at reasonable production costs and schedule timing are changing the development chain in the automotive industry. Mainly regarding automotive lightweight construction based on the use of lightweight materials, meaning that building materials of low specific density and high-strength can be used, automotive engineers and designers are being challenged everyday, through the introduction of many new materials for their applications. And for this, new design aims and methodologies should be developed [Batalha, Damoulis & Schwarzwald, 2003]. Vehicle body-in-white (BIW) complains usually complex geometry, irregular pressed parts. Forming these blanks is normally a combination