Fatigue Analysis Of Magnetorheological Fluid Mount Rubber Based Onfluid-structure Interaction

With the development of new energy vehicles,new challenges are posed to NVH performance,and magnetorheological mounts that can be adjusted in real time to adapt to various working conditions have been emphasized.As a vibration isolation element in the power system,magnetorheological suspension is always subjected to the excitation force of different frequencies and amplitudes in operation,and the durability of the suspension is always tested,and its fatigue research is of great significance.When magnetorheological suspension operates,fluids and solids interact,and the properties of liquids change accordingly under the influence of the magnetic field generated by the current.Therefore,it is necessary to establish a magnetic circuit model to study the magnetic circuit structure,and in order to simulate the magnetorheological suspension performance closer to the real reality,this paper adopts the multi-physics method to study and explore a fatigue research method suitable for engineering applications.An electro-magnetic model of the magnetic circuit structure is established to predict the magnetic field distribution of the magnetic circuit.The Navier-Stokes equation of fluid dynamics is used to establish the equation of motion of the fluid in the inertial channel,and the magnetorheological suspension damping characteristics are analyzed.The experimental design method was used to analyze the sensitivity of each magnetic circuit parameter to the damping force,determine the number and range of parameters,and provide theoretical support for the research on magnetic circuit.Considering that the fluid model is suitable for steady-state situations,the model is checked and the extended equation is fitted.With large damping force and adjustable coefficient as the optimization goal,and external geometric size as the variable,the multi-objective optimization design is carried out.The results show that under the radial channel magnetorheological suspension structure,the core depth has the least influence on the damping force,and changing the inertial channel height can quickly improve its damping performance.The addition of extended equations further improves the accuracy of fluid models.The multi-objective optimization design can improve the strength and uniformity of the magnetic flux density of the magnetorheological suspension damping gap.After optimization,the damping force of magnetorheological fluid increases,the current continues to increase after magnetic field saturation,the controllable force increase is small,and the damping performance has been fully exerted when the field is full.Considering the interaction between solid and fluid and the nonlinear magnetization law of magnetorheological fluid and industrial pure iron,a multiphysics prediction model is established.Establish a coupled model of solid and fluid,and bring material parameters and liquid parameters fitted by electro-magnetic simulation into the fluid-structure interaction model to predict the performance of the suspension.The motion law of fluid and solid force is analyzed,and the dynamic stiffness and static stiffness of the suspension are calculated.By comparing with the dynamic characteristics test results,the accuracy of the model is proved.The results show that this method has high precision,and the motion law and dynamic characteristics of solid and liquid conform to relevant theories.The fatigue prediction model was established,and the fatigue prediction method suitable for magnetorheological suspension was studied.According to the fatigue life research method,a rubber fatigue prediction model was established and its accuracy was verified by experiments.The fatigue prediction methods under traditional rubber suspension and fluid-structure interaction were studied,and the results were compared.At the same time,according to the characteristics of magnetorheological mounting,the influence of current and magnetic circuit structure on fatigue life is studied.The results show that the fluid-structure interaction model can accurately simulate the performance of magnetorheological mount,and the fluid-structure interaction has a great influence on the fatigue life of rubber,while the magnetic field and magnetic circuit structure have almost no effect on rubber fatigue,and it is feasible to consider fluidstructure interaction to improve the fatigue simulation accuracy of magnetorheological mount.