Research On The Friction Vibration And Thermal Coupling Of Brake Joint Surface

The rotating joint surface is a common connection structure and contact form in mechanical systems,such as the braking system of various transportation tools,the machined surface such as drilling and grinding,and the problem of vibration friction and thermal coupling generally exists between rotary joint surfaces.The friction between rotating joint surfaces usually causes vibration of the system,which has an impact on the stability of the system,such as vehicle braking noise and vibration,machine tool cutting vibration,so as to reduce ride comfort and machining accuracy.Therefore,it is great significance for the study of the friction vibration and thermal coupling of the rotating binding surface.In order to study the vibration and thermal coupling characteristics of the relative movement between the joint surfaces,a more common disc brake is selected as the research object.The influence of the parameters of the brake disc joint surface on the vibration characteristics of the brake system and the influence of the thermal coupling characteristics of the brake joint on the brake during the working process are emphatically analyzed.This research provides a theoretical basis for controlling the vibration and thermal stability of the rotating joint surface.The main contents of this paper are as follows:(1)On the basis of related literature on dynamic analysis of braking system and thermal coupling problems at home and abroad,a summary of the current research status and development trend at home and abroad in this field is completed.The relevant data on brake dynamics modeling and dynamic characteristics at home and abroad are analyzed,and its research results are grasped.The existing problems are found.Combined with the research direction and characteristics of the research group,the specific tasks and tasks of this thesis are worked out.(2)Based on the fractal theory,a three-dimensional fractal normal contact damping model of friction disc and friction disc is established,and the influence of micro morphology parameters on contact damping is completed.Based on the three-dimensional fractal theory,the three-dimensional fractal normal contact damping model of friction disc and friction disc is established by using fractal dimension,scale parameter and actual contact area.The influence of the parameters on the contact damping model is studied by changing the different micromorphology parameters.(3)A system dynamic model of braking bonding surface considering the contact characteristics of joint surface is established.Based on the three-dimensional fractal contact stiffness and the contact damping model,the dynamic model of the braking interface was established.The influence of the braking stability on the friction plate and the average roughness of the friction plate was studied.(4)The thermal structural coupling simulation analysis of the braking system simplified model is completed.Based on the simplified model of braking system,the distribution of temperature,stress and deformation in the radial direction,axial direction and circumferential direction of the brake disc and the friction plate under the condition of emergency braking are studied.Brake disc thermal fatigue failure causes.(5)The three-dimensional fractal and finite element temperature rise model of brake combined surface is established.Through the established three-dimensional fractal temperature rise model,the effect of the micro-topography parameters on the maximum temperature rise of the joint surface was studied by numerical simulation.By using the established finite element model of temperature rise,the temperature variation of the rough surface with fractal features during the relative movement was studied.(6)Completed the braking system temperature rise test and vibration test and other experiments.Based on the built simulation platform of vehicle braking system,experiments of temperature rise and vibration of friction plates and friction plates under different operating conditions were carried out through different emergency braking modes.