| The vibration of automobile pipeline is caused by the external environment of automobile body,and the continuous dynamic load may lead to the local fatigue failure of the pipeline system.To ensure the safety of vehicle,the design of pipeline system structure and vibration control are very important.Based on the actual demand of automotive pipeline system design and development,combined with the leakage problem of transmission oil cooling system pipeline in the running process of a certain model,the vibration characteristics of pipeline are studied,and the structural improvement scheme of pipeline is proposed.The research is mainly conducted from the following aspects:Firstly,on the basis of analyzing the vibration principle of the automotive pipeline system,the finite element model of the oil cooling pipeline system was established by using the three-dimensional modeling software,and its structure was simplified.The frequency response analysis and fatigue analysis of the pipeline system were carried out by the finite element software of ANSYS Workbench,and the maximum stress was calculated at the frequency of85.333Hz.And the minimum service life is 2.045×10~6 cycles,lower than the standard design life of the pipeline 10~7 cycles.Secondly,combined with pipeline simulation analysis,the shaking table vibration test of oil-cooled pipeline was carried out,and frequency sweep test was carried out on the pipeline system.According to the actual resonance position of the oil-cooled pipeline,the frequency corresponding to the maximum amplitude point of the pipeline was identified as 82.544Hz,and then fixed frequency vibration was carried out at this frequency.The results showed that the pipeline leakage occurred 33h after vibration,and the leakage failure position was at the connection of the transmission oil pipe and the temperature control valve thread nozzle,which was basically consistent with the dangerous weak point position obtained by the simulation analysis.Finally,a structural improvement plan is proposed for the parts of the pipeline system that are prone to failure.The structure of the pipeline system is improved by adjusting the wall thickness of the pipeline,increasing the fixed support points and changing the direction of the pipeline.At the same time,the finite element simulation calculation of the improved pipeline structure was carried out one by one,and combined with the vibration test results of the test bench,an optimal scheme was selected,which showed that the pipeline could vibrate for 60h at the frequency of 113.4Hz,thus greatly improving the service life of the pipeline. |
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