Research On Automobile Suspension Rubber Bushing Structural Optimization And Methodology

Suspension is an important component of a vehicle,which has to satisfy the performance of handing,ride and NVH simultaneously.As the flexible joint of suspension linkage sets,rubber bushing’s stiffness is playing a vital role in suspension performance.While structure optimization of rubber bushing is the foundation of meeting stiffness objective.Reasonable optimization and design technique ensures that integral stiffness of rubber bushing agrees well with the design goal.Consequently it illuminates the disparity between vehicle performance and the target,cuts down on the test and time cost of repetitive adjustment.Most studies in the field of rubber bushing have been carried out in the bushing stiffness affecting vehicle dynamics,viscoelastic properties of rubber-like material,durability estimation,bushing formula,static mechanical simulation etc.Researchers have not treated structure optimization of rubber bushing in much detail.Therefore,the study on structure optimization of rubber bushing becomes extremely indispensable,which are discussed in this paper combining vehicle projects in writer’s company.To begin with a brief summary of rubber properties and six common hyperelastic constitutive models was presented.We deduced equation of engineering strain and stress of each constitutive models,as well as described the least square fitting method of constitutive coefficients.The test on rubber-like material was conducted,including uniaxial、biaxial and planar test.This paper obtained some results of constitutive coefficients fitting by dividing the test data to small strain level,medium strain level and large strain level with differential technique.Then the effectiveness and range of application of six hyperelastic constitutive models were compared.The coefficients obtained from test data fitting were applied to rubber bushing stiffness simulation.The analysis verified the coefficient fitting reliable.Secondly,this would be followed by a detailed presentation of how the structure coefficients such as bushing outside diameters、inside diameters and length affect stiffness and a description of coupling properties between different orientation’s stiffness.According to the coupling properties,we can adopt the half-experience design to optimize bushing structure,whose radial、axial and swing stiffness match the design goal.In the last section,a structural optimization example of rubber bushing was presented.Given that the stiffness of bushing do not match goal,Meshworks was employed to set structure dimension of origin bushing as shape parameter here.Then a design matrix was obtained by DOE analyze of design variables with application of Isight.Stiffness of all directions was calculated by Abaqus to establish the stiffness and shape parameter approximate Response Surface Model.New size parameters matching target were obtained after numerical optimization of approximate model.Stiffness of new bushing structure was calculated again to verify the all direction of stiffness matching the goal.The conclusion of this paper can be outlined as follow: the structure optimize method can solve the rubber bushing design problem which has highly coupled stiffness of different orientations.It improves the efficiency and accuracy of bushing designand stiffness matching.Besides,it avoids repeated parameter adjustment and test in the bushing structure design process.This methodology can be effective for shortening debugging time and manufacturing cost.Therefore the optimization technique has a wide application prospect in engineering design.