The Mechanic Characters Analysis Of Rubber Bushing In Random Vibration Excitation Used In Subframe

In the last decades, rubber bushing and rubber bearings as a damping element arewidely used in automotive chassis, mainly in the connection between engine ortransmission and frame, as well as the suspension system. They are used mainly to decaythe engine, transmission and road vibration delivered to the body. So the NVHperformance can be greatly improved. Therefore, it is very importance to study themechanical properties and fatigue properties of rubber components.Because of the rubber material nonlinearity and geometric nonlinearity, the design ofrubber products is very difficult, and the study of rubber mechanical properties and fatigueproperties is stay in the stage of experiment. Because of the recent development of finiteelement method, finite element analysis software can be used for rubber nonlinear finiteelement analysis. So the design cycle has been reduced greatly, and the accuracy andreliability of the product have been improved.Firstly, a FE model of the rubber bushing was constructed by HyperMesh’ mappedmesh based on the3D model. Then the FE model was introduced into ABAQUS/CAE, andappropriate materials, units, contacts and other features were selected, and then the specificboundary conditions were setted to simulate the rubber bushing test excited by randomvibration. Then a simulation of the rubber bushing was performed, and the stressnephogram can be obtained, compared which to damaged parts in the experiment toconfirm the reliability of the simulation.Secondly, the fatigue test of rubber bushing has been finished. Static stiffness anddynamic stiffness have been determined through tests. The test results validate the finiteelement analysis is correct.Thirdly, the general idea of optimization for rubber bushing structural parameters hasbeen introduced. The structure of the rubber bushing Optimization of parameters has beenfinished with HEEDS software (mainly for the small displacement stiffness requirements),and achieved automatic control of the optimization. The optimization results can be used as a rubber bushing improvement program.Finally, limited by the maximum stress of rubber bushing, and the static stiffnesscurve of the bushing, topology optimization of the rubber bushing have been performedwith the OptiStruct software. The results of the topology optimization provide project tothe improved designing of rubber bushing.Based on the super-elastic model of rubber, the nonlinear finite element simulation ofthe rubber bushing has been finished. The comparison between the simulation andexperimental results showed that the position with maximum stress on the rubber bushingstress nephogram is just the position where the rubber bushing fatigue crack start. So it isvery useful of the nonlinear finite element analysis in the design of rubber bushing. Theoptimization results of the rubber bushing provide a feasible method for the bushing’simproved design.