Study On The Influence Of Test Paramaters On An Engine Connecting Rod Fatigue Simulation Test Results

Connecting rod as one of the key components of internal combustion engine,its working reliability is very important for the normal operation of engine.Domestic and foreign scholars have done some research on its reliability.As one of the main methods to study the reliability of connecting rod,fatigue simulation test has been widely used.The connecting rod fatigue simulation test rig is used as a simulation test equipment,and its parameters have a direct influence on the performance of the equipment.During the fatigue simulation test of connecting rod,the main test parameters affect the test results are the test frequency and the connecting rod installation process.The research object of this paper is a self-developed fatigue test rig for connecting rod.Based on the numerical calculation method,the numerical analysis of the natural frequency of the test bench is carried out first.By comparing its natural frequency and test frequency,analyzing whether the resonance of the test bed will occur within the test frequency range.Secondly,using the numerical calculation method,the stress of the connecting rod and the tension pressure sensor at different test frequencies is calculated.By comparing the stresses at different frequencies,the influence of test frequency on the fatigue simulation test results of connecting rods is obtained.The results show that this factor has little effect on the test results and can be ignored.Finally,the influence of the connecting rod installation process parameters on the fatigue simulation test results is calculated and analyzed.The parameters in the connecting rod clamping process mainly include two aspects.One is the interference amount of the connecting rod small head,the othet is the angle between the connecting rod and the vertical direction.The results show that within the critical interference volume,the small head interference has no effect on the fatigue test results of the connecting rod.When the interference exceeds the critical value,the failure location of the connecting rod changes.At the same time,the installation angle has a great influence on the test results,which can not be ignored.In order to improve the test accuracy and correct the test results of the fatigue test,this paper quantitatively studies the influence of interference and inclination on the fatigue simulation test results of connecting rods by comparing the test results with the theoretical calculation results.The research results show that the theoretical test results are quite different from the fatigue test results of the connecting rod before the influence of interference and inclination is corrected.Based on the above research,the theoretical calculation model of the correction coefficient of interference and dip angle was obtained,and the accuracy was verified by the test data.It provides guidance for the selection of test parameters in the test process,and a verification method and theoretical basis for the correction of fatigue test results.