The Study And Application Of Simply Modeling Method In Mounting Rubber Bushing

The NVH performance is one of the important indicators for evaluating the comfort of a vehicle.When the car is running,it is mainly stimulated by the engine and the pavement roughness.The mounting system is an important component that connects the engine and the car body.The vibration isolation performance of mounting system has an important influence on the ride comfort of thevehicle.A good mounting system not only can effectively reduce the excitation from the engine,but also can extend the life length of the engine and other components.When the MPV vehicle was tested for mounting vibration isolation rate,it was found that the Z-axis vibration isolation rate of the was not sufficient,and it was necessary to optimize it and propose improvement measures.However,the vibration isolation rate analysis result based on the full vehicle finite element model is different from the experimental result.it is because the modeling method of mounting rubber bushings in the full vehicle finite element model is too simple and can not show its true dynamic characteristics,and then analysis accuracy of vibration isolation is not accurate.This article can be divided into two major parts: one is The study of simply modeling method in mounting rubber bushing;the another is the analysis and optimization of the mounting system vibration isolation rate.The main work of this paper is as follows:1.First of all,explained the basic information of the problem MPV,the basic theory of mounting system vibration isolation rate,the experimental method of suspension vibration isolation rate,and obtained the vibration isolation rate of the right mounting rubber bushing in Z direction at different speeds.2.Several characteristics of rubber materials are described,and the super elasticity and viscoelasticity of rubber materials are discussed in detail.Several commonly used superelastic mechanical models of rubber materials were analyzed,and the basic test methods for rubber materials currently used in the world were introduced.The basic viscoelastic mechanical model of rubber material was analyzed,and the mechanical equations of the five-parameter Maxwell model were deduced and it is used as the mechanical model to describe the mounting rubber bushing.3.The method for obtaining the dynamic characteristics of the mounting rubber bush is discussed.The basic theory of the finite element analysis method and the finite element analysis software ABAQUS are introduced.By describing the dynamiccharacteristics of mounting rubber bushings,the basic flow of finite element analysis was determined.With reference to the experimental procedure,HyperMesh was used to pre-treat the mounting rubber bushings,and conditions were set in ABAQUS.Finally,the dynamic stiffness curve and hysteresis angle curve of the rubber bushings were obtained.It is the basic for the simply modeling method in mounting rubberbushing in the full vehicle model.4.A new simplified model of mounting rubber bushing was established.The vibration isolation rate of the mounting system was analyzed,the dynamic stiffness of the passive side of the mounting system was analyzed,and the model of the mounting system truncated model was analyzed.From the perspective of analyzing the dynamic stiffness of the attachment point on the passive side of the mounting system,the reason for the insufficient vibration isolation rate is divided.5.From the point of view of strengthening the mounting bracket structure,the dynamic stiffness of the attachment point on the passive side of the mounting system is optimized.After the three optimization schemes are tried,the results are found to be unsatisfactory;from the perspective of the modal distribution of the full vehicle,the model is discussed.By analyzing the modal strain energy and the modal contribution,the reason of the insufficient dynamic stiffness of the attachment point on the passive side of the mounting system is found.After targeted enhancement,the dynamic stiffness of the passive side of the mounting system is effectively improved,and the vibration isolation rate of the mounting system is also improved.The prominent point of this paper is the a new simplified modeling method for mounting rubber bushes,which greatly improves the accuracy of vibration isolation analysis in the finite element model of the full vehicle,and has important theoretical and practical values.