Application Of Surface-flattening Technology In Blank Development Of Automotive Cover

The process planning of automotive panel sheet metal forming is a complex task. The distribution and path of strain and stress in sheet metal is much intricate during deformation. We should take into account the problem of deformational coordination in different place to avoid the emergence of rip or wrinkle in process planning because of overladen attenuation and control the springback of sheet metal within the permissive scope. With the demands of the above, Die design of automotive panel depending on traditional experience is waste of time and energy in optimizing technological parameters and probably couldn't abtain prospective aims. Recent years, with the development of non-linear finite element technology in metal plasticity deformation area, numerical simulation and analysis method hav been a key technology in industrial design and production process. It can largely improve product quality, reduce product cost and shorten development cycle by applying such technology.This research derives from NSF and named as"The Independent Research of High-speed Simulation and Optimal Process Planning aiming at the Formability of Automobile Panel"(NO.50575080). Based on the simulation software of FASTAMP with updated finite element inverse approach and dynamic explicit algorithm, which is developed by State Key Laboratory of Plastic Forming Simulation and Die & Mould Technology of HUST, paper presents a novel any complex surface flattening, which could develope any complicated surface.Researching abundant traditional algorithms of developing surface and comparing their advantages and disadvantages respectively, author puts forward a new algorithm for transforming surface into plane by using incremental finite element method. The traditional algorithms, such as geometry flattening, mechanics flattening and geometry flattening/ mechanics revision, separately discuss part geometric feature and deformation with load, which results in their's large calculation and low precision. Considering both geometrical feature and deforming condition, a new algorithm for transforming any complex surface into a plane presented by combining the method of geometry unfolding with finite energy-based model actually solves the problem of flattening any intricate surface. Paper validates the correctness and precision of this algorithm by large number of double curved surface. It shows that it not only could be applied in the field of sheet metal forming, but also could be widely applied in the field of aircraft, automobile, costume-designing, toy-making, shoe-making etc. Furthermore, paper applies the flattened results in fimite element inverse approach with initial guess and triumphantly attains high precise blank. All this will reduce the times of mould-test of automotive cover and then decrease product cost, shorten development cycle and improve product quality.