Research On The Dynamics Effect Of Brake Disc Surface Groove On Braking And Groove Optimization

The brake is an important component to ensure the safe operation of the device,so it has become an important scientific research project to study the braking characteristics of the brake in the braking process to ensure the speed and effectiveness of braking.Various studies have shown that a smoother friction surface does not provide better braking performance.Instead,the surface groove structure has the advantages of changing the interface contact state to achieve friction reduction and noise reduction.Therefore,based on the commonly used braking conditions of high-power wind turbine disc brake,this paper studies the effect of groove parameters on various braking characteristics during braking by establishing parameterized grooves on the surface of the brake disc,and provides a reference for the design and optimization of the parametric groove structure on the friction surface.The main research contents and results of this paper are as follows:(1)According to the multi-body dynamics theory and a certain type of wind turbine brake,the brake rigid-flexible coupling model of the mechanical assembly is established.Based on this model,the parameterized grooves are established on the friction surface of the brake disc,and the groove brake discs with different parameters are brought into the rigid-flexible coupling model under the common brake working conditions for mechanical dynamics simulation to study the influence of the groove parameters of the friction surface of the brake disc on the brake vibration characteristics.The research results show that the angle and cross-sectional shape of the groove have a greater influence on the braking process,while the width and depth of the groove have less influence on it.During braking,the axial amplitude of the brake disc is related to the braking efficiency.The larger the axial amplitude,the higher the braking efficiency.(2)Based on the mechanical dynamics simulation results,the influence of groove parameters on the braking force between the friction interfaces is analyzed.It is concluded that the change of the groove parameters of the friction surface of the brake disc have different effects on the force fluctuation between the friction interfaces.Based on the collision theory,the influence of the groove parameters on the collision process is analyzed,and it is concluded that the change of the groove angle has a greater influence on the collision process between the brake and the groove,and the cause of this phenomenon is numerically solved.The research results show that the grooves at a certain angle make the braking force between the upper and lower friction interfaces appear for zero period,and the zero period difference of the upper and lower braking forces increases the amplitude of the braking component.Within a certain angle range,the greater the groove angle,the more violent the collision process between the brake pad and the groove.(3)A simplified brake thermal-mechanical coupling model is established based on friction heat generation theory and material heat conduction conditions,and the angular velocity and axial vibration amplitude of the brake disc with time in the multi-body dynamics results are loaded into the model as boundary constraints.By analyzing the changes of the temperature field and stress field of the brake components during braking,the influence of the groove parameter changes on the friction heat generation,dissipation and stress is obtained under the premise that the groove affects the brake vibration characteristics.The research results show that during braking,the temperature accumulation value of the brake disc is related to the change of the angular velocity of the brake disc.The maximum stress of the brake disc is mostly at the groove,and the brake disc of some parameter grooves generates a much higher than average stress in the friction zone,forming a local hot spot.(4)By comparing the braking characteristics of symmetric-asymmetric grooved brake discs involved in braking,the difference between the two structural grooves on the braking process is studied.Based on a certain basic angle,arc-shaped grooves with different shapes are established on the friction surface of the brake disc,and the influence of the arc-shaped structure in the quadrant on the braking performance is studied.Based on the skew distribution theory and the effect of parameterized grooves on the braking process,the groove parameters on the surface of the brake disc are optimized.The research results show that the asymmetrical grooves on the upper and lower surfaces of the brake disc have the advantage of improving braking efficiency,and also significantly reduce the axial amplitude of the brake disc.The arc groove has a high influence on the braking efficiency.The optimal groove foundation angle is generated between 67° and 72°.This paper studies the dynamics effect of the brake disc surface groove on the braking process,and obtains the results and related laws of the influence of groove parameter changes on brake vibration characteristics,brake efficiency,brake component temperature and stress changes.This provides a theoretical basis for the optimization and determination of the final groove structure parameters.