Mechanical Property Analysis Of Rubber Spring And Structural Optimization Of Rubber Suspension

For heavy vehicles,the driving conditions are often harsh,and the suspension system determines the ride comfort and reliability in the driving process.Therefore,many new suspension continues to be applied in heavy vehicles,rubber suspension mainly uses a pair of rubber spring as bearing and vibration damping components,the use of rubber material unique nonlinear characteristics,can achieve good driving characteristics.Compared with other suspension types,rubber suspension also has the characteristics of light weight,maintenance free and low cost.In this paper,a company is developing a rubber suspension as the research object,aimed at the rubber spring and balance beam assembly research.The main research contents are as follows:1.The constitutive model theory of rubber material was summarized,and the constitutive model parameters were obtained by combining with the mechanical test of rubber material.The uniaxial tensile test was carried out on the rubber sample,and the stress-strain data obtained from the test were fitted according to different hyperelastic constitutive models.Through comparison,the Ogden constitutive model with the best fitting effect was selected and the parameters of the hyperelastic constitutive model were obtained.Dynamic thermal mechanical analysis(DMA)test was carried out to obtain the dynamic modulus data of rubber materials.According to the generalized Maxwell viscoelastic constitutive model,the parameters of the test results were identified by the least square method,and the parameters of the viscoelastic constitutive model were obtained.2.The rubber spring is one of the most important load damping components in the rubber suspension system.The finite element model of the rubber spring is established.The static characteristics of the rubber spring were analyzed by statics,and the error was 4.6%compared with the static stiffness test results.The hysteretic curves of rubber springs with different frequencies and amplitudes were obtained by using implicit dynamics analysis.The dynamic stiffness values were calculated by ellipse method.The results show that the dynamic stiffness is affected by amplitude and frequency.Finally,according to the analysis results of static and dynamic characteristics of rubber spring,the forced vibration model of rubber spring was established to calculate the dynamic response of the system under specific working conditions.3.For rubber suspension,the structural performance of metal structural parts determines the safety of rubber suspension.The structural performance of the balance beam assembly is analyzed by finite element method,electric strain measurement technology and displacement measurement system.After establishing the finite element model of the balance beam assembly,the static simulation of the balance beam assembly under the four working conditions of full load bending,emergency turning,emergency braking and full load torsion is carried out.The analysis results show that the balance beam assembly can meet the basic requirements of use.The electric strain measurement technology and displacement measurement system were used to test and analyze the balance beam assembly under full load bending condition.Compared with the simulation results,the error was within the allowable range,which verified the reliability of the finite element model.4.Lightweight design has always been the main development direction in the automotive field.Structural optimization of the balance beam assembly with the largest mass proportion in rubber suspension has potential application value.The variable density method was used to optimize the topology design of the balance beam assembly structure.The minimum strain energy was taken as the objective function and the percentage of volume was taken as the optimization constraint to obtain the topology optimization results under different working conditions.Combined with the actual working requirements and machining characteristics,the optimization scheme was developed,and the weight of the optimized model was reduced by 7.9%compared with the original model.The static test of the optimized model is carried out,and the results show that the optimized model can improve the structural performance on the basis of lightweight.