Fatigue Analysis And Structure Improvement Of The Heavy Truck Lateral Thrust Rod Based On Combined Strain Test

Because the original design method of the company is more conservative,it is difficult to realize the lightweight design of the lateral thrust rod of a heavy truck.This paper attempts to use a new design method to improve the structure of the lateral thrust rod in order to achieve the goal of light weight.The new design method mainly includes two parts:the load of the lateral thrust rod which is derived by the strain test,and the strength of the lateral thrust rod which is checked by fatigue life analysis.In strain test,based on the principle of Wheatstone bridge,a plurality of the strain gauges are combined into axial force,bending moment,torque sensor,and is pasted on the lateral thrust rod.these sensors are calibrated to correct the measurement error of the sensors.After completion of the calibration,the lateral thrust rod is assembled on the vehicle,and strain time-domain data is tested on the actual road.Finally,the functional relationship between the strain and the load is established,and the strain time domain data is converted into the load time-domain data of the lateral thrust rod.Compared with the original design method,the load of the lateral thrust bar obtained by this method is closer to the reality,which improves the accuracy of the strength analysis.In the fatigue life analysis,this paper mainly predicts the fatigue life of the ball head,the connecting rod and the ball core of the lateral thrust rod.Firstly,the static finite element model of the original lateral thrust rod is established,and the relationship between the load and the maximum stress of the dangerous region of the ball head,the connecting rod and the ball core is obtained by CAE analysis.Then,the load time-domain datas are converted into the maximum stress time-domain datas of the dangerous region of the ball head,the connecting rod and the ball core.Finally,the stress time-domain data and the S-N fatigue curve of the materials are introduced into the fatigue analysis software,to carry out the fatigue life.The analysis results show that the three parts of the original lateral thrust rod have very high residual strength.The new lateral thrust rod is obtained by optimizing the structure of the original lateral thrust rod.After that,the fatigue life of the ball head,the connecting rod and the ball core of the new lateral thrust rod is predicted according to the same method.The analysis results show that the new lateral thrust rod can meet the design requirements.Finally,the new thrust rod has been successfully verified by the reliability test,which proves that the new thrust rod can meet the design requirements,and also proves that the new design method is feasible.Compared with the original design method,the new design method is more conducive to achieve lightweight of the vehicle.It is a more advanced design means,and has certain application value.