FSI Simulation And Abnormal Structure Noise Analysis Of Hydraulic Shock Absorber

Shock absorber, as an indispensable damping elements of vehicle suspension system, its dynamic characteristics has a great compact on vehicle comfort performance, handling directional stability and ride performance. In recent years, the main noise sources of vehicle have been better controled, the hydraulic shock absorber of the abnormal noise is relatively exposed, this abnormal sound reducing the vehicle quality and affecting sales. New research shows that indicate that the clearance impact of the piston and the fluid of shock absorber, the alternation of static friction and moving friction and the interaction process between hydraulic shock absorber throttle slice and shock absorber liquid all result in impact to the piston. Then the transference of impact yield abnormal structure noise. They indicate that the clearance impact of the piston and the fluid of shock absorber, the alternation of static friction and moving friction and the adherence between valve and piston all result in impact to the piston. Then the transference of impact yield abnormal structure noise. However the microcosmic high frequency fluid structure interaction process mechanism between hydraulic shock absorber throttle slice and shock absorber liquid is very complicated, which has important effect on the vibration of the valve, the deformation and stress distribution and also determines the fatigue strength of throttle slice, and ultimately determines the shock absorber damping characteristics, the occurrence of abnormal noise and life.Actual hydraulic shock absorber throttle slice is usually constituted by the same thickness of multi-piece valve superposition together in order to ensure the shock absorber damping characteristics and reduce the possible occurrence structure of abnormal noise. For these advantages, research of the vibration characteristics of different throttle slice thickness and stress distribution on the shock absorber damping characteristics and structure of abnormal noise effects, and to improve the quality and life of shock absorber have great engineering value.To further analyze the interaction process mechanism between hydraulic shock absorber throttle slice and shock absorber liquid to the shock absorber damping characteristics and the abnormal structure noise effects, In this paper, adopt a single throttle slice (hereinafter referred to as shock absorbers A) and superposition throttle slices (hereinafter referred to as shock absorber B)of two kinds shock absorbers for research, using the dynamic mesh fluid-structure interaction technology of ANSYS CFX software, two kinds shock absorbers throttle slices dynamic characteristics and shock absorber liquid high flow is simulated analysis under sinusoidal inlet velocity loads conditions. The valve vibration acceleration curve, the stress and strain distribution and shock absorber liquid flow field characteristics has been obtained.By comparing the vibration acceleration curve and shock absorber liquid flow field characteristics distribution of two different structures throttle slices of shock absorber, the results show that the superposition throttle slices has a smaller vibration acceleration amplitude, which can reduce the shock absorber structure of abnormal noise. Comparison the stress and strain distribution of throttle slices, obtained that that the superposition throttle slices has a better intensity, and further through the shock absorber noise bench test to verify the correctness of the simulation results. The above analysis shows that based on dynamic mesh technique of One-way fluid structure interaction analysis method can better achieve the microcosmic high frequency fluid structure interaction process between hydraulic shock absorber throttle slice and shock absorber liquid analysis and calculations.This article first establish the geometry model of the throttle slices of shock absorber and shock absorber liquid with the 3d solid modeling software Pro/E Wildfire3.0 and ANSYS 3d solid modeling module DesignModeler. Secondly, proposes a method which takes ANSYS Workbench as a platform, adopt the dynamic mesh technique of ANSYS CFX to calculate the transient fluid dynamics of flow field, and then get the flow field characteristics analysis result to exert in the structure model by"the body load"that is in the form of CFX Pressure for transient structural dynamics simulation in Simulation module, finally obtained the dynamics characteristics of solid models, which form completing the fluid-structure interaction analysis that is to say One-way fluid structure interaction analysis.Finally, to prove the feasibility of this method, this paper comparative analysis research of a simple model of similar problems which adopted Two-way fluid structure interaction analysis method and based on dynamic mesh technique of One-way fluid structure interaction analysis method, the simulation results within an acceptable error range, which shows that based on dynamic mesh technique of One-way fluid structure interaction analysis method is feasible, at the same time compared the simulation results with the empirical formula results, indicating the correctness of simulation methods.