A Sheet Metal Forming Simulation of a Fuel Filler Door Considering the Behavior of Air in a Die Cavity

摘要

During a sheet metal forming process (especially when outer panels are involved), air trapped between a blank sheet and an upper/lower die tool can become highly compressed, ultimately influencing blank deformation. To prevent this problem, vent holes are drilled in die tools based on expert knowledge and experience. This drilling process takes much time and thus can increase lead time. Therefore, the influence of vent holes in sheet metal forming process should be optimized for reducing development costs. CAE can be used to analyze the behavior of air in a die cavity during a forming process, incorporating both the elasto-plastic behavior of a blank sheet and the fluid dynamics of air. This study presents a sheet metal forming simulation that simultaneously simulates the behavior of air in a die cavity. The die velocity during the forming process affects the pressure of the trapped air. To include air behavior (based on the ideal gas law and FPM) in an industrial sheet metal forming model, a parametric study is performed for efficiency including reduction of the CPU computational time. The proper technique for reducing the CPU computational time is then applied to a forming simulation of a fuel filler door to correctly understand the process. In this study, the commercial software PAM-STAMP (TM) and PAM-CRASH (TM) is used.