CAE Analysis And Optimization Design Of Car Door System

Along with the increasement of car sales and growing population of privatecars, auto industry has already become a sunrise industry in China since thebeginning of21st century. Recently, several provinces have issued the “purchaseorder” from which shows that China has become the automotive industry country.But the sustained development of automotive industry is also a double-edged sword.On the one hand, the short supply leads to a reduction of automobile productioncycle time and a fall in the quality of automobile. Only a year in2012, China’s autorecall has amounted to3.2millon. On the other hand, the sharply increase of vehiclepopulation brings tremendous pressure on road trips and traffic accidents occurfrequently. Based on the above situation, the thesis selects car door system forstructural performance and passive safety performance analysis. In addition, throughthe matching optimization of part thickness, material and structure, front and backdoors response in the collision make synchronous improvement.Firstly, the thesis analyzes the structural performance of car door system andsums up a complete set of analysis modeling process. According to the process, ahalf car model that can be used for stiffness analysis and a door assembly model thatcan be used for modal analysis are both established. Stiffness of drooping, frame,belt line, torsion and free modal frequency are evaluated. The result shows that thestructural performance meets the design standards well.ECE R95regulation of side impact is collated and analyzed. According to thetechnical requirements, positive rigid collision of mobile barrier model is carried outto make sure that the force-dispalcement curve of each block falls within the rangeas regulated. In this way, the mobile deformable barrier model is proved to beaccurate. A side impact model is then established and through the simulation of sideimpact, a conclusion is reached that total energy in the process maintainsconservation and hourglass energy remains under5%. So the result of simulation iscredible.To meet the need of multi-target inspection, the concept of regional stiffness isput forward. By analyzing the influence of part thickness on regional stiffness,sensitive parts are selected as optimization variables, such as front door inner panel,side door beam and rear door inner panel. In addition, the invasion of car doors,invasion velocity of B pillar and total mass are all set as target values.18sets ofsample points are obtained by way of orthogonal experiment. With these data,response surface model is established and a multi-objective optimization of sideparts thickness is carried out with the method of NSGA-Ⅱalgorithm. In combination with F test result, the most significant factors of each targetvalue are selected out as variables for a further material matching optimization.Materials that have been adopted are B340/590DP, CR420/780TRIP and B340/LA.Furthermore, structure improvement scheme that aims at the defects of force transferpath, B pillar and side impact beam is put forward. Finally, the three indexes areimproved by25.22%,25.84%and19.83%respectively. That is to say, a balance hasbeen found between the invasion of front door and back door. The passive safyperformance of side impact is promoted.