Research On Temperature Characteristics Of Shock Absorborbased On Data Mining

At present,the double-cylinder hydraulic shock absorber is widely used in the automobile suspension system.It generates a damping force through the throttling action of the throttle valve to convert the energy of the vibration into heat energy,thus attenuating the vibration of the suspension system.Part of the generated thermal energy causes the shock absorber components and the oil temperature to rise,and the other portion is dissipated by heat exchange with the outside through the outer cylinder wall.During the continuous working process of the shock absorber,the temperature change has many effects on its performance.Firstly,the damping force decreases with the increase of the temperature due to the change of the viscosity,causing the phenomenon of “temperature decay”,which makes the vehicle smooth performance become more worse.Secondly,when the temperature rise of the shock absorber reaches too high and exceeds the limit temperature of the rubber,it will accelerate the aging of the sealed original parts and cause high temperature oil leakage;in addition,the higher temperature is also likely to cause the cavitation effect of the working fluid,resulting in the shock absorber characteristic distortion.In order to prevent and avoid the above problems,it is necessary to study and master the temperature characteristics of the shock absorber under complex internal and external conditions.To fully study the temperature characteristics of the shock absorber,and then predict and optimize the design of the shock absorber,different analytical models were established.Some scholars tried to build a mathematical model of the temperature characteristics of the shock absorber from the perspective of thermodynamics,but due to the complex internal structure of the shock absorber,and the heat transfer forms are diverse,the establishment of thermal machine coupling mathematical model is bound to simplify the actual physical structure,so the confidence of the research model still needs to be improved.In addition,the temperature rise of the shock absorber is a process of dynamic cycle of heat absorption and heat dissipation.If the conventional coupling simulation is used,it needs to be iterated for a long time and the performance of the processor need to be high.Another part of the scholars use the bench test method,although the method is successful in the research and application of the mechanical damping characteristics of the shock absorber,it is difficult to change the internal design parameters of the shock absorber,so this method is time-consuming and laborious,and the research efficiency is low.It can be seen that how to build a model with high precision and high efficiency is a key issue in studying the temperature characteristics of the shock absorber.Based on this,this paper will study the modeling of the temperature characteristics of the shock absorber.The specific research work is as follows:(1)Thermal mechanism analysis of the shock absorber.Analyzing the structure and working principle of the shock absorber to find out the heat generation mechanism of the shock absorber.Then according to the knowledge of engineering heat transfer,the process of radial heat transfer from the inside to the outside of the shock absorber is determined,and the types of heat transfer processes,the method of heat calculation and the required hydrothermal parameters are clarified for subsequent experiments and Modeling research to lay the foundation.(2)Experimental study on the temperature characteristics of the shock absorber.Taking full account of the external environmental factors of the shock absorber,the MTS850 shock absorber test bench was retrofitted to simulate the external environment of the shock absorber.Then,according to the experimental conditions,the experimental procedure of the temperature characteristics of the shock absorber is developed,and the temperature characteristic experiment of the shock absorber under the external environment change is carried out.In order to determine the influence of loading conditions,ambient temperature and air flow rate on the temperature characteristics of the shock absorber,it also provides basic data and proof-of-test basis for the establishment of the research model.(3)Establishment of CAE simulation model.The CAE modeling method of " Thermal equivalent " was proposed for the first time,that is,the equivalent parametric simulation model for the mechanical damping characteristics and heat transfer characteristics of the shock absorber was established by means of the AMESim simulation platform,based on the " Thermal equivalent " method.The damping characteristics of the shock absorber are simulated by the damping characteristic model,and then the heating power of the heat transfer model is calculated to simulate the temperature characteristics.By comparing with the experimental data,the simulation curve is roughly consistent with the trend of the experimental curve,and the maximum error of the equilibrium temperature is 10.6%.At the same time,through the " Thermal equivalent " modeling method,the influence of frictional heat generation of the movable parts inside the shock absorber on the temperature characteristics of the shock absorber can be fully considered.Separate modeling and simulation can also reduce the time of iterative calculation of the model in multi-phase coupling and improve the efficiency of modeling and simulation.(4)Data mining modeling and CAE simulation model correction.Through the analysis of the cause of the error in the CAE model,the feature set including the four variables of heating power,loading speed,ambient temperature and air velocity is determined,and the target set including the equilibrium temperature difference and the equilibrium time difference is determined.Through the Latin square hypercube sampling,50 sample combinations were designed,and then bench experiments and simulation experiments were carried out to obtain sample data of data mining.Then,the sample data is normalized,so that the values of different features are quantized to the same interval,and then the support vector machine regression model is built using Python language.The K-fold cross-validation method was introduced to evaluate the model's accuracy and the model was tuned by the variance-bias tradeoff.Finally,the data mining model is used to correct the CAE simulation results and compare with the experimental curves,the error of the equilibrium temperature under multiple operating conditions is less than 5%,and the maximum error of the equilibrium time is about 300 s.Finally,compared with the existing research methods,the results show that the research method is higher than the existing methods in accuracy and efficiency.In summary,the method is effective and can be used for the research and estimation of the temperature characteristics of the shock absorber.