| At present, automobiles becoming one of the necessary parts of human being’s life which causes the worldwide problems of oil energy consumption and environmental pollution. It’s necessary to conduct the research on automotive lightweight design in order to avoid these two problems. The structure optimization design for auto parts is one of the main ways to achieve the automotive lightweight design. However, current studies rarely take the uncertainty load into consideration of the influence on design result, and there are few scholars checking the fatigue life of design results.Aiming at this situation, this paper selected the control arm of automobile as the research object, used the targeted method- structure topology optimization design, at the meantime considering the effect of random road and limit working conditions to the design results respectively. For both the topology optimization design results, this paper rebuilt their models, and estimated the fatigue life of the models based on the nominal stress method. The results show that the design result based on random road has a better performance in terms of the strength, stiffness, lightweight and fatigue life requirements. The main work is as follows:(1) First, we briefly introduced the suspension and control arm, and then adjusted the suspension topology model in ADAMS/Car according to actual model. Second, we calculated the tire contact force of the selected limit working conditions which was used to obtain the control arm’s load by the suspension static simulation. Last, suspension dynamic simulation was performed to obtain the control arm’s load curve using the established road model corresponding to the selected random road.(2) First, we briefly described the variable density method. Second, we built the finite element model of control arm boundary model for topology optimization design based on the actual model. Third, the topology optimization simulations of the two cases were performed with the minimum compliance constraint and the minimum volume objective. And at last, we would check whether the results meet the strength, stiffness and lightweight requirements.(3) First, the fatigue life estimation methods were described, and then established the S-N curve of the control arm based on the material S-N curve. Second, we selected six load conditions for the fatigue life estimation of the control arm, obtained the stress of both optimization design results and the original model of the six load conditions by using the finite element method. With the S-N curve and the stress, the fatigue life can be estimated to check whether the results meet the fatigue life requirements. |
