Finite Element Analysis And Optimization Design Of Vehicle Ventilated Disc Brake

With the advancement of automobile production technology and the development of social sciences,people's requirements for vehicle safety and comfort have increased year by year.The driving safety of the vehicle is largely affected and restricted by the performance of the brake.The performance of automotive brakes has a direct impact on the safety of vehicle drivers and their occupants.The function of the vehicle brake system is not only to slow down the car in motion to stop,but also to ensure that the car maintains a stable speed under certain conditions(such as downhill).Brakes usually contain disc brakes and drum brakes.Compared with drum brakes,disc brakes are simple in structure and easy to dissipate heat.Due to its stable brake efficiency,it's widely used in automobiles.However,during braking,it is easy to produce braking efficiency failure,through the analysis of temperature field and stress field in braking process,it can effectively improve the noise,vibration and thermal fatigue caused by "hot spots" during braking.How to improve braking performance has become an important issue in automotive research.In this paper,the finite element analysis method is used to analyze the finite element analysis and thermal-structural coupling of vehicle ventilated disc brake.The structural parameters of the brake are optimized by the analysis results.The main research contents include:(1)Research and analyze the development status of automobile disc brakes at home and abroad,the research level of finite element analysis and the development trend of future brake research,and clarify the research direction,research content and implementation methods of this paper.(2)Select the ventilation brake disc in the brake system as the analysis object,and establish a three-dimensional model according to the brake structure of a car.Through the analysis of the force of the wheel during braking and the analysis of the ground braking force and braking torque,the dynamic parameters during the braking process are determined.Based on the study of contact analysis theory,the finite element model is established to determine the physical property parameters of the material with temperature and the displacement load boundary conditions.By analyzing and calculating the maximum load value under the emergency braking condition,the braking condition is determined,which provides the basis and suggestion for the design and improvement of the ventilated brake disc.(3)Without considering friction heat generation,to make static analysis and modal analysis for ventilated disc brakes.The static analysis analyzes the stress distribution of the brake disc,which provides a reference for the strength check of the rear brake disc.During the modal analysis study,the pre-stressing modes of the brake disc under different brake fluid pressures are extracted and analyzed.The analysis result provides a reliable basis that preventing brake disc resonance,designing brake disc which pressed variable load,the selection of brake condition,and prevention of brake disc damage.(4)To explain the basic method of thermal-structural coupling,and analyze the stress field and temperature field by finite element coupling analysis method.Based on theoretical analysis,the finite element simulation analysis of the thermal-structural coupling of emergency braking conditions is carried out.Through the simulation analysis,the temperature field,stress field and contact friction cloud distribution of the brake disc are obtained,and the following conclusions are drawn: the stress field cloud map and the temperature field cloud map of the brake disc are displayed under the emergency braking condition of the brake disc.It is a non-axisymmetric distribution;the frictional contact area of the brake disc is a concentrated area of the high temperature zone and the high stress zone.With the emergency braking of brake,the temperature field cloud map and the stress field cloud map of the brake disc are gradually close to the axisymmetric distribution.On the basis of the thermal-structure coupling simulation,it is determined that the "hot spot" of the brake disc is easy to appear,which provides basis and suggestion for the design and improvement of the ventilated brake disc.(5)Comprehensive analysis of the finite element results to optimize the structure of the brake disc.Firstly,the venting hole is designed on the surface of the brake disc to facilitate the heat dissipation of the brake disc.Secondly,the size of the aperture is optimized.Due to the spacing of the ribs,the size of the aperture is optimized,and the aperture is optimized by the optimization result.The optimization results show that the aperture in four millimeter is more conducive to ventilation and heat dissipation.Finally,compared with the analysis of the temperature field distribution and stress distribution before and after,this scheme is reasonable.