| The noise of disc brake pairs has always been a difficult problem for enterprises and researchers.Many factors induce the noise of disc brake pairs,among which the influence of particle flow of the third body has not been paid much attention.The generation of such noise is considered to be a problem of multibody dynamics or tribology.As the disc brake is exposed to the outside environment,sand,wear debris and water mist may enter the brake disc,while the surface of the brake pair will also produce particles due to wear.This results in three-body contact.Three-body and two-body have different friction characteristics,and a new friction model is needed to describe them.(1)Based on the existing two-body contact theory and three-body contact theory,a three-body friction model with particle flow is established in this paper,taking into account the nonlinear characteristics of friction coefficient.The model was used to analyze the influence of different parameters on the contact type,and then four key parameters were selected to study their influence on the friction coefficient.The results show that the geometric parameters of the particle and the mechanical parameters of the brake block have influence on the nonlinear characteristics of the friction coefficient.(2)Using the newly established friction model,the dynamics numerical analysis of the single block brake model was conducted,and the effects of the parameters of particles and brake blocks on the stability of the system were studied.The results show that stickslip vibration occurs when the excitation velocity is low,and the phenomenon of stickslip can be reduced by increasing the geometric parameters of the particles.At very low excitation velocity,the geometric parameters of the particles and the mechanical parameters of the brake block can also reduce the chaos interval.(3)The friction model was also used for numerical analysis of the two-block brake model,and it was found that the limit cycle amplitude could be reduced when the connection stiffness and particle geometric parameters were properly configured,and the chaotic interval could be reduced by adjusting these two parameters when chaotic vibration occurred. |
