| Heavy and low speed vehicles such as special trucks and armored vehicles have strict requirements on the wear resistance characteristics of brake discs.The smooth and nonsmooth surface topography of brake discs has a significant impact on the wear resistance characteristics of brake discs.Therefore,in order to obtain an effective way to improve the wear resistance characteristics of brake discs,it is necessary to reveal the mechanism of the impact of surface topography on the wear resistance characteristics of brake discs.Based on the relevant theory of thermo-mechanical coupling,took the brake disc of heavy-load and low-speed vehicle as the research object,the smooth brake disc model of a heavy-load and low-speed vehicle and the brake disc with non-smooth surface topography structure have been established successively.The finite element thermo-mechanical coupling analysis has been carried out on a large number of three-dimensional models of brake disc.After optimizing and eliminating some models,the numerical simulation of the brake disc finite element model has been sorted into three levels for friction and wear tests,Characterized the braking process of the brake disc,verified the influence of the non-smooth surface morphology structure on the wear resistance of the brake disc itself,creatively propose the ventilation duct structure,and analyzed the results of the temperature change,stress and strain,friction coefficient fluctuation,noise and wear rate of the brake disc under the braking condition.This article mainly conducts the following three aspects of research:(1)Several 3D models of heavy-load and low-speed vehicle brake discs were established using CATIA 3D software.The 3D models were imported into ANSYS software and converted into finite element models for model simplification.The theoretical basis involved in the thermal-mechanical coupling simulation analysis was described in detail,and the thermal-mechanical coupling module was used for simulation.(2)The simulation analysis of three levels includes smooth brake disc of the first level,straight groove and bend groove were added to the second level,and air inlet structure was innovatively added to the third level.The purpose was to further simulate and analyze the influence of air inlet on wear resistance of brake disc based on morphological structure of non-smooth surface.The results of each cloud diagram showed that the design of each level had obvious superposition effect in improving the wear resistance of brake disc: the maximum braking temperature under 60 km/h braking condition was reduced from 169.028 ℃to 138.725 ℃;the setting of grooves enlarges the contact area between friction surface and air and interrupted the continuity of transfer of friction heat source during braking process;The setting of air intake duct guides air flow impact and enhances air flow rate inside the groove,further made the friction heat inside the groove dissipate quickly,effectively restrains the spread and accumulation of friction heat into the brake disc,and enhances the dispersion failure effect and wear-resistance characteristics of friction heat of the brake disc.The simulation analysis was divided into three levels.The first level is smooth brake disc,the second level is added with straight groove and curved groove on the basis of the first level,and the third level is innovatively added with air inlet duct on the basis of the second level to further simulate and analyze the impact of air inlet duct on the wear resistance characteristics of brake disc on the basis of non-smooth surface morphology.The three levels are progressive layer by layer,and the results of each cloud chart show that the design of each level has obvious superimposed effect on improving the wear resistance of the brake disc: the setting of grooves increases the contact area between the friction surface and the air,and interrupts the continuity of friction heat transfer during the braking process;The setting of the air inlet duct guides the impact of air flow,enhances the air flow rate in the groove,further makes the friction heat in the groove dissipate rapidly,effectively inhibits the diffusion and accumulation of friction heat into the brake disc,and enhances the dissipation effect and wear resistance characteristics of the brake disc friction heat.(3)Five different brake disc samples were prepared and characterized by friction and wear test.The maximum temperature,friction coefficient fluctuation,maximum noise and friction and wear rate before and after the test were measured with relevant instruments.Comprehensively analyzed and compared the advantages and disadvantages of five brake disc samples,selected the best sample and applied for patent.The research results clarified the influence mechanism of the surface morphology structure on the wear resistance of the brake disc,revealed the dynamic change characteristics of various parameters of the brake disc of the heavy-load and low-speed vehicle in the braking condition,and obtained the targeted theoretical basis for the development of the brake disc of the vehicle with excellent wear resistance characteristics,which had practical application significance for the design and optimization of the surface morphology structure of the brake disc of the heavy-load and low-speed vehicle. |
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