Study on Fatigue Life of Vehicle Fuel Tank Under Random Vibration Environment

Abstract The working environment of oil tank is complex and changeable. Aiming at the problem that it is difficult to predict the high cycle fatigue life of a certain vehicle fuel tank, The fatigue life of the tank was studied. Firstly, the natural frequency and modal shape of the structure are obtained by identifying modal parameters of the structure using Eigensystem Realization Algorithm (ERA). Then, the simulation model is established by SolidWorks, and imported into ANSYS for modal analysis. Compared with the bench test, the results show that the errors between dynamic characteristic of modal simulation and modal test are acceptable, which verify the accuracy of simulation model. Finally, the fatigue life of fuel tank is analyzed by frequency domain analysis method in ANSYS nCode DesignLife. The results show that the weak position of the oil tank vibration is always unchanged under multiple power spectral density (PSD) spectrum types, and its life decreases with the increase of PSD amplitude at low frequency. To further verify the accuracy of numerical simulation results, the PSD spectrum corresponding to the shortest life tank will select for random vibration fatigue life experiment in the future.