Automotive Covering Parts Of Surface Denting Numerical Simulation

As energy shortage and increasingly serious air pollution, the car is becoming more and more attention of lightweight, cars as an important part of automobile body covering parts, and to reduce the quality in order to reduce energy consumption and air pollution is a veryimportant role.And automotive covering parts, especially outer covering parts is an important factor to cause consumers to buy, its production quality directly affect the sales of cars.however some surface defects such as dents, distortion and rupture, often appear on the automobile outer covering parts, appear this kind of defect may be drawing force is not enough or rebound, whatever the reason, once appear this kind of defect, is time consuming work of refinement automotive covering parts or repair mold, resulting in great waste of time cost.Surface sag is a kind of do not conform to the unreasonable phenomenon, we expected as Gao Jiangban application, this kind of phenomenon is more and more obvious.General company and dalian university of technology in 2008, a joint research project, the surface defects of automobile covering parts forming mechanism and the correction method.Experimental results show that in the corner of the sheet with mild collapse, the same is true in the process of production, and simulation is always predict defects of sheet metal upward bulge, although raised the amount of basic same, but the direction of the springback completely wrong, to this hypothesis is that there may not be fully detailed simulate the stamping process, also may be existing stamping simulation software exists some error on the algorithm.This article mainly aims at the first hypothesis, accurate simulation of the stamping process, in-depth study the influence of the stamping before and after springback for surface defects, mainly divided into the following three steps:1) on the basis of the project from mould, to build a simulation model, as much as possible, reduce the error brought by dimensions, stamping analysis was carried out on the built model, forming limit diagram analysis in the post-processing, the thickness of the cloud, etc.To explore some of the parameters (drawbead, pressure control mode, blank-holder gap circle, unit type, material type) for sheet metal formability.On the basis of guarantee the formability, springback calculation, analysis of springback results.2) general simulation software in the stamping process are the default upper die down to the lowest, after stamping, stamping process, including the return parts, namely the upper die and blank holder ring down exactly, upper die and blank holder circle after the return to a certain degree, the pressure to coil, upper die to return, until completely leave blank holder, will the whole return parts considering the simulation calculation, analysis of the whole process of springback.3) Used in the simulation software of drawbead is equivalent drawbead, that does not take into account the actual shape of drawbead, can only simulate the size of the drawing force, this will create constant error and the actual, in order to accurately simulate the stamping process, must consider the actual drawbead shape, to find a way to to join the actual shape of the drawbead on the mould, the springback calculation.Exploration work of this paper, in order to explore the root causes of automobile covering parts surface concave provides the theoretical basis and real simulation analysis, for further simulation software in the surface sag and the actual production of made outstanding contributions to the cause of the rebound in the opposite direction.