Dynamic Simulation And Structural Optimization Of The Light Truck

Based on the theory of Multi-body System Dynamics, the models of the mainlyautomotive subassemblies including front and rear suspensions were built inkinematics and dynamics software, ADAMS/Car. Then, all subassemblies wereassemblied as a full vehicle. And systemic simulation and analysis off frontdouble-wishbone suspension were performed. The parameters which changed in badtrend were optimized and put forward the modifying strategies. Through a series ofsimulation about handling stability and ride comfort, the effect after modificationwere expressed by the comparison of the original and the modified, which analyzedthe front suspension's influence to full vehicle in simulation. The whole article include seven chapters:The chapter one reviewed on the growing history, primary task, research methodand the application in the research of vehicle system dynamics of Multi-body systemdynamics. Furthermore, it briefly introduced the research about handling stabilityand automobile ride comfort. The summarization about this article was done.The chapter two introduced the software-ADAMS and the expression ofgeneralized coordinate, movement joint, movement in view of Multi-body systemdynamics. Then, interpreted how to compute dynamic equation and analyzeinitialized condition. This chapter briefly discusses ADAMS' theoretical basementand calculate methods, which became the stabilized foundation for application ofADAMS.In chapter three, with some pickup truck for prototype, the major components'dynamic model were built in Multi-body system dynamics software-ADAMS/Car,then assembly the full vehicle which have 146 degrees. The front axle is consist ofdouble wishbone suspension whose model was built in UG according to engineeringdrawing offered by manufacturer, then lead into ADAMS to require its quality, size.The rear axle is consist of dependent suspension whose elastomer is leaf spring andthe absorber' characteristic was required by test. The tyre model adopt the type ofDELFT or SWIFT according to different simulating station. The engine model adoptthe one in ADAMS/Car.The chapter four introduced the application of ADAMS/Car in research anddesign to suspension. The suspension is one of automotive principal subassembly,which is most important to handling stability and ride comfort. The traditionaldesign methods are experiential design, mathematic calculation and geometricalconstruct etc, the design can satisfy the requirement but the precision and efficiencyis low, can't keep up the upspeed design requirement, new design method must beadapted in order to shorten the development period and cut cost. ADAMS/Carmodule has the professional kinematics and dynamic analysis template forsuspension, all kinds of suspension can constructed conveniently and more the thirtykinds of parameters curves about the suspension can be made rapidly. Thekinematics and dynamic analysis arm at front double wishbone suspension. Manyparameters concerned with handling stability were computed. Some parameter withbad tide in the change was optimized in ADAMS/Insight and the improving measureto key position of suspension was put forward. Then the effect after improvementthrough comparison can be attained. This kind of method could evaluateperformance of suspension rapidly and precisely, optimize parameters and designstructure which take on a widespread foreground to apply.The chapter five, in the basement of the chapter three and four, the two handlingstability station was done, steady static circular simulating test and pylon courseslalom simulating test. In comparison of the original vehicle model, the model afteroptimization to suspension and the model installing antiroll-bar, we can attain thatthe project of optimizing key point of front suspension can augment turning radiusand increase automotive understeer characteristics, the project of installingantiroll-bar can decrease rolling angle effectively and improve ride comfortcharacteristic. These two schemes mended either handling stability or ride comfort.The chapter six, the ride comfort simulating test was done. B-class road modelwas built through white noise first-order filtered in Matlab. According to GB/T4970-1996,the fullvehicle model ran straightly at 60Km/h. The acceleration signal of vertical vibrationin front and rear axle, floor were measured, then disposed to get relevant autopowerspectrum density curve and Root mean square value. Through comparison ofvehicle original and modified, a conclusion can be attained that the measureoptimizing suspension key point depressed Root mean square value of verticalvibration acceleration, ameliorate ride performance, the measure installingantiroll-bar influence the ride comfort little.The chapter seven was sum-up of whole-length which depicted this article'primary content and conclusion. The application to kinematics and dynamicssimulation in suspension and full vehicle' design would decrease capitals indevelopment and shorten the cycle of exploitation.In conclusion, dynamic simulation is efficient way to develop suspension and fullvehicle. The Multi-body system dynamics software packages provide powerful toolsfor the dynamics analysis of suspension and full vehicle. The dynamic simulationtechnic center around the Multi-body system dynamics will play more effective rollin suspension and full vehicle product development.