Research On The Experiment And Continous Process Numerical Simulation Of Autobody Panel's Dent Resistance

The dent resistance of exterior panels is very important for autobody quality. Many researches on the dent resistance of exterior panels focused on basic experiments and numerical simulation based on FEA. But the design of experimental system is not standardized, the reliability and accuracy of experiment needs to be improved. Although many useful studies had been taken and the precision has been greatly improved in numerical simulation, but implicit algorithm made the calculation results difficult to converge, as well as too long calculating time. The simulation results show that it is difficult to apply to the pratical exterior panels with complex geometry.In this paper, the dent resistance of the double-curved autobody panel had been investigated. The main work included the analysis of double-curved exterior panel′s static dent resistance and establishing a high precision test system with single point incremental loading. Based on ABAQUS the numerical simulation of continuous process from forming, springback to static dent resistance deformation had been studied .The main conclusions are.1,Incremental load test on single point can keep the uniformity in load points every time, which reduced the error caused by the different load location in the test. This method can shorten the testing period and improve the experimental efficiency.2,Experimental study shows that the panel's static dent resistance can be improved by increasing holding force of forming or selecting specimen with high yield stress.3,Continuous process numerical simulation of autobody panel's dent resistance was established based on ABAQUS. The precision of simulation model was improved by comprehensive consideration of material properties, geometry characters, processing conditions, work harden, sheet metal thinning, springback and so on.4,The relationship in different stages was fitted between local dent load and dent depth. And small displacement sinking stiffness K1 and big displacement sinking stiffness K2 were regarded as important indexes to evaluate exterior panel′s static dent resistance.5,Influence on the precision of simulation model by element mesh size and material anisotropy was studied. And the precision of simulation modelwas improved by selecting the best element mesh size and adopting Hill yield criterion. The deviation between test results and simulation results was decreased from 19-26% to 11-19%.6,Simulation analyses showed that for the same material increasing the panel's thickness could improve the dent resistance of autobody panel.Through the research the evaluation of exterior panel′s static dent resistance will be more accurate , This work will be helpful to establish uniform and standard system of evaluating exterior panel′s dent resistance.