Friction Force Modeling And Stick-Slip Vibration Analysis Of Three-Body Disc Brake System

The empirical friction models often used in the research on the instability of the brake pair induced by friction often fail to reflect the intrinsic relationship among the relative motion speed,the friction interface characteristics of the brake pair and the friction force.However,the existing tribological experiments show that the morphological and mechanical properties of the friction interface have a significant effect on the stick-slip vibration of the brake system.Therefore,it is of great significance to establish a friction model that reflects the internal relationship among the above three,and then analyze the influence of relevant parameters on the system's stick-slip vibration.Firstly,based on the tribological experiments,this paper establishes a physical model that reflects the main characteristics of the friction interface of disc brake pairs.Then,based on the two-body elastoplastic contact theory and a new three-body contact model established in this paper,taking into account the creep effect of the brake pad asperities,this paper establishes the two-body and the three-body friction model that reflect relationship among the relative motion speed,the friction interface characteristics and the friction force,and analyzes the influence of related parameters on the curve relationship between speed and friction force.Finally,this paper establishes a single-degree-of-freedom dynamic model of the braking system introducing the two-body and three-body friction models respectively and analyzes the influence of relevant working condition parameters,morphological parameters and mechanical parameters on the bifurcation characteristics and stick-slip vibration of the braking system.The results show that the height of the asperities of the brake pad and its root mean square value,the plastic index,the micro-elastic modulus and damping parameters of the brake pad asperities,the maximum(small)particle diameter and particle density have a significant effect on the curve relationship between speed and friction force,the static and dynamic bifurcation characteristics,the amplitude and frequency of stick-slip.The above research provides new ideas for the study of the friction interface characteristics of the brake pair,especially the effect of the particles on the stick-slip vibration of the brake system.