| After the research situation of suspension dynamics modeling and simulation,structural optimization, and fatigue life is introduced, the multi-link suspension dynamicmodel is built according to the actual mathematical model from the company. Then, thetypical extreme working conditions are chose to simulate the entire suspension model toextract the loads of control arm. After that, the finite element model of the control arm isestablished and its structural strength and modal are analyzed. In view of themanufacturability of control arm, the size optimal proposal is raised and the structuralstrength and modal of optimized control arm are re-verified. Finally, the fatigue life of theoptimized control arm is estimated and the fatigue strength is also checked through thefinite life design method for nominal stress. In this dissertation, main research works arefocused in the following four aspects:(1) Dynamic modeling and simulation of the multi-link suspension. Thedynamic model of multi-link suspension is built on the base of actual mathematical model.The simplicity of the model is raised and the flexible connection elements in suspensionare also described in detail. As a motivation for dynamic simulation of the entiresuspension, the grounding force of tire is calculated by vehicle parameters. Then, the loadof each node of control arm was extracted and the force and moment balance are alsoverified.(2) Finite element analysis of control arm. The finite element model of controlarm is established according to the actual mathematical model. A detailed description ofthe finite element modeling, which involves cleaning-up geometry, meshing, mesh qualitycontrol, simplifying solder joints is represented. Then the stiffness, strength, naturalfrequency and other data of the control arm are reached by the application of inertia relief,which will provide reference to the performance validation after the optimal design.(3) The structure optimization of the control arm. The reason of using size optimization to the control arm is intensively analyzed and the steps and precautions of thesize optimization are also concretely defined. After the size optimization, the stiffness,strength, natural frequency and other properties are verified.(4) The fatigue life estimation and fatigue strength checking of the control arm.Based on the12working conditions from the company, the staple6working conditions areraised, and this is the basic working conditions for fatigue life research. Then the finite lifedesign method for nominal stress is applied to estimate the fatigue life and check thefatigue strength of the control arm. After that, the results of the fatigue research areanalyzed in detail and the appropriateness of working conditions is also intensivelydiscussed.Through the above research work, the optimization design and fatigue liferesearch of the control arm have been completed. The optimization proposal and fatiguelife research will provide reference to not only the design of suspension control arm butalso some other important parts of mechanical products in the future. |
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