dc.description.abstract | The engine hood is one of the major outer skin panels in an automobile body structure. The commercial quality requires the engine hood being free from cracks and wrinkles. In addition, the surface stretch at the center region of the engine hood needs to meet a strength requirement. Though the stamping technology on the forming of an engine hood has been developed by both the automotive industry and die makers, the success of the die design still relies mainly on the experience of professional engineers. Also, in response to the current market trends and the consumer concerns, the engine hoods look more and more diverse, making the die design even more difficult.
Since the shape of an engine hood is mainly produced in the drawing operation, the die addendum design is the key to the success of manufacturing a defect free product. In order to analyze the addendum design, the part shapes of different engine hoods were first surveyed and the geometric characteristic features were identified and categorized. The existing die addendum designs corresponding to those engine hoods collected were also reviewed and the design parameters were constructed. The finite element analysis was then conducted to simulate the drawing process of an engine hood with flat addendum die face, i.e., without die addendum design. The defects occurred in the part were examined and the factors causing these defects were then analyzed. The preliminary study was then performed to examine the influence of the process parameters, such as stamping die angle, binder surface shape, and die open line shape on the defects occurred in the part. Based on the simulation results, the optimum design for the die addendum face was then investigated. The effects of the design parameters constructed in the present study on the occurrence of the defects were then examined and a systematic design guideline was proposed.
In order to validate the proposed design guideline, actual engine hoods were stamped with the dies designed according to the finite element analysis. The production part shapes, thickness distributions, and the stretch at the central region were then compared with those obtained from the finite element simulations. The consistent agreement between the product parts and the simulation results confirms the validity of the design guide proposed in the present study for stamping an engine hood. | en |