Optimization Of Suspension Rubber Bushings For The Handling Stability And Ride Performance Of Distribution Drive Electric Vehicles

Rubber bushing as connection between chassis, body and power transmission systems,because of its super-elastic, viscoelastic, elastic-plastic characteristics, can play tocompensate for manufacturing tolerances, reduce vibration and noise, and load transfer.Also it has a great effect on the vehicle’s handling stability and ride performance. Asdistributed drive electric cars combine the tire and motor together, makes the unsprung massincrease and the motor has a high-frequency excitation, thus, make a very significant impactto the performance of suspension system. As the mechanical properties of bushings issensitive to frequency and amplitude,the modeling of bushings has higher requirements.So it is very necessary to establish nonlinear rubber bushings.In this paper, some work has been done around the optimization of suspension rubberbushings for the handling stability and ride performance of distributed drive electricvehicles, the main contents include the following aspects:First of all, discuss the super-elastic and viscoelastic of rubber material, study theimpact of amplitude and frequency on rubber mechanical properties. Then make a briefintroduction on the history of the model for the rubber bushings.Secondly, study the constitutive models of the rubber super-elastic and viscoelastic.According to the requirement of constitutive models, take some static tests on the rubbermaterial uniaxial tensile test bench and dynamic tests on the dynamic mechanical analyzer.Use the visco-elastic-plastic model in Abaqus to express the mechanical properties of rubber,establish the finite element model of rubber bushings and verify the accuracy of the finiteelement model.Again, the mathematical expression of several common models for rubber bushings arecompared, Berg three-unit model is selected by contrasting from the calculation speed, accuracy and other factors to express the rubber bushings. According to rubber bushings testdate on the viscoelastic material testing machine and finite element simulation data, theparameters of the model are recognized in Matlab with sub-unit identification method.Then, the Berg three-unit model is applied to the Adams suspension dynamics modelby GFOSUB user subroutine, and compare the difference with Kelvin bushing model fromstatic and dynamic suspension simulation. And the Berg three-unit model is verified moreaccurate on the expression of the rubber bushing’s dynamic stiffness. The next, establish thevehicle multi-body dynamics model, analyze and compare the different impact betweendifferent bushing models on handling stability and ride performance simulation calculations.Finally, based on the establishment of vehicle multi-body dynamics model, optimizethe parameters of the rubber bushings for handling stability and ride performance, In orderto reduce the workload,sensitivity analysis has been done to find the key directions of thebush and the key parameters before optimization. The Isight software provide optimizationalgorithm, Adams simulate the model, Matlab process the results of simulation, unite threesoftware to optimize. At last, compare the difference of vehicle performance before andafter the optimization.