Research On The AA7075Vehicle Body Structure Based On Side Impact Crashworthiness

With more and more attention to the safety and environmental performance of thecar, high strength aluminum alloys gradually get into the carmakers’ vision for itsadvantages of high strength, low density and high recovery performance. The7-seriesaluminum alloy as the highest hardness strength aluminum alloy series has been takenmore and more attention. Aluminum alloy7075is a typical representative of7-seriesaluminum alloy, which belongs to the Al-Zn-Mg-Cu hard aluminum. AA7075has theadvantages of high hardness, high strength, good abrasion resistance, corrosionresistance and thermal formability, etc.Both at home and abroad has made detailed regulations on vehicle side impactsafety. Our official release the regulations "car side impact occupant protection" in2006, which puts the vehicle side impact safety into the vehicle mandatoryimplementation standards. In side collision, B pillar as the main protection structureplays a very important role in resisting side impact forces, transmitting the forces tothe other side impact structures around uniformly and efficiently and thusguaranteeing the occupants safety space to release occupants injury.This paper applied AA7075material to the main body side collision parts todecrease vehicle body weight while guarantee the side impact crashworthiness.The first chapter introduced the research background, and analyzed the researchmethods and research status on the car side impact, vehicles lightweight, thenpresented our country’s side impact regulations and the technical route and feasibilityanalysis of this paper;The second chapter analyzed the mechanical properties of high strength aluminumalloy7075, obtained the static and dynamic mechanical tests data by static anddynamic Hopkinson tensile test, selected the Johnson-Cook material constitutivemodel to accurate represent the mechanical properties of AA7075, then determinedthe parameters of the mechanical constitutive model;The third chapter mainly carried out a particular car model vehicle side impactsimulation analysis, and verified the accuracy of the model vehicle simulation, thenbased on the vehicle side impact analysis chose the main deformation region to be thesimplified side impact model to improve the computational efficiency and comparedthe result between the simple side impact model and the vehicle side impact model; The fourth chapter mainly applied the7075aluminum alloy material to the innerand middle strengthen B-pillar panels of the simplified simulation model in sideimpact simulation. And compared the safety between the replaced and originalsimplified side impact model after side collision and on the consideration of the sideimpact safety performance, through further optimization of the thickness and structureto achieve the ultimate lightweight structure;The fifth chapter chose the mechanical clinched joint as connections method inconsideration of the aluminum alloy’s unique physical and chemical properties, thenanalyzed the mechanical clinched joints forming and mechanical property betweenAA7075plates to obtain the connection CAE model used in the side impactsimulation. Based on the connection model, doing some structural improvements onthe B pillar to achieve the effect of lightweight with the guarantee of meeting thesafety requirements.