The Research Of Vehicle-used Metallic Material's Dry Friction Characteristic

The vehicle system is a complex mechanism, a mass of metallic accessories are assembled together with various joints and has a lot of metallic vibration-noise and friction problem. So the research of vehicle-used metallic material's dry friction characteristic is important for theoretical analysis and practical engineering.This thesis studies on the metallic material's dry friction according to a great quantity of home and abroad research. On the basis of predecessor's fruits, this thesis deeply researches on two theoretical models of dry friction damper, one is the single-degree spring damper vibration model, and another is the Mindlin theoretical model. The metallic material's dry friction characteristic is measured by the quasi-static and dynamic test platforms which are designed by us. The experimental results are compared with the results of two models of dry friction damper, and show the validity of the Mindlin theoretical model. At the same time, the changing laws of the effective stiffness and effective damper with the dimensionless relative displacement are demonstrated. Also, the changing trends of friction coefficient with the dimensionless relative displacement and the changing trends of surface tangential stiffness with normal load are analyzed.Based on the metallic material's dry friction characteristic, the FEM numerical model of metallic material's dry friction is created by the nonlinear FEM code MSC.Marc. Compared the FEM model results with the experimental results and theory results; it can be found that the FEM model results have higher coincide degree with the experimental and theory results. It can help to analyze dry friction damper characteristic in the practical engineering, and can provide a reliable calculation basis to the vehicle and engine design and the corresponding NVH simulation analysis.