Simulation Of Closed Force Of Car Door Seal System And Optimal Design Of Variable Section

Benefited from the super elasticity of rubber materials,the automotive sealing system is able to fill the inevitable gap between the body opening parts and the closing parts,thereby playing an important role in vibration reduction,appearance beautification,sound insulation,dust prevention and water resistance.The traditional sealing system is designed with a single section or a double section joint,with simple structures and few geometric variables,however,the door system contours are mostly complex three-dimensional surfaces.Under the influence of three factors,namely,the difference of sheet metal gap,the rotating compression of the door and the large curvature of the installation contour,the local st ress and sealing performance of traditional sealing system fluctuate greatly,making it difficult to meet the requirement of the overall closing force of the target.By taking the front door sealing strip of a certain car type as an example,the material nonlinearity,geometric nonlinearity and contact nonlinearity of the door closure sealing process are studied.Facing the complex space contour of the car body,the compression model of the 2d and 3d sealing system of the car door,including the 3d assembly analysis of the sealing strip are established,to simulate the prestress caused by the bending of the sealing strip,and the fluid-solid coupling simulation model is used to calculate the internal air damping force of the sealing strip.Finally,the optimization design of variable section sealing system for passenger car door is presented,and the two-dimensional theory and three-dimensional numerical simulation are utilized to make it meet the target closing force requirement.The contents of this work are as follows:(1)Firstly,a two-dimensional plane simulation model of the sealing strip in the process of door closing is established using Abaqus,including the selection of material model of sealing strip,selection of element type in simulation model,b oundary condition,and the setting of solution control.Then,compression load tests on existing sealing strips are conducted,so as to verify the accuracy of simulation model and simulation results.(2)A reasonable sampling and quantitative analysis of the clearance value of the door/frame sheet metal is made through the real car experiment,and the distribution pattern is obtained.From the figure,for roof,b pillar,threshold,and hinge,the sheet metal gaps between them and the flat section are different but approximate equivalent,while the corner is the transition area of the sheet metal gap changes,the change of this area is relatively large.Coupled with the installation of the contour of the large curvature and door rotation compression,it is proved that the "piecewise-Cumulative" method has large error in the traditional two-dimensional model based on plane strain.(3)Three-dimensional simulation model of door closing is established based on Abaqus,and the sealing force is solved without rega rd to the air of the bubble tube in the sealed strip;the air damping force of the sealing strip exhaust hole is solved by the flow-solid coupling simulation analysis of Mpcci combined fluent and Abaqus,and t he total sealing force is obtained by adding the two.The accuracy of the three-dimensional simulation model is verified by the closing force experiment.(4)Taking the sealing strip of the vehicle as an example,the method of modeling the variable section seal system is illustrated.First,four sections of the large curvature corner section of the first-line sealing strip are extracted to carry out three-dimensional finite element analysis respectively,in order to be investigated for the dynamic change characteristics of the closing force,based on the bending torsional deformation and the inherent stress of the sealing strip under the influence of large curvature.Then the remaining four approximately straight sections of the first-line sealing strip are considered,this is still based on the traditional two-dimensional finite element simulation data because the pressure direction for them is almost constant.Overall closing force and sealing performance requirements are finally met with multiobjective optimization redesign of sealing section.