Simulation study on the vibration durability test of an automotive plastic fuel tank based on fluid–structure coupling

In this study a new simulation technology based on fluid-structure coupling is to solve the problem of plastic fuel tank lifting lug fracture during vibration durability test, which has not been reported in the existing literature. The basic principle of fluid-structure coupling is summarised and the finite element model (FEM) of the fuel tank system established. Modal simulation analysis is carried out, and the FEM is updated and verified via the modal test method. A harmonic response analysis of the fuel tank system is performed. Simulation results show the maximum stress at the lifting lug is 29.69 MPa in the Z-direction vibration, exceeding the allowable fatigue strength. The resonance occurred, which is consistent with the result of the vibration durability test. To enable the fuel tank to pass the vibration durability test, this study proposes to optimise the fixture, thereby enhancing the natural frequency of the entire fuel tank system and avoiding an excitation frequency of 30 Hz. Through the harmonic response analysis and test verification, the fuel tank passes the vibration durability test. Therefore, the numerical simulation method based on fluid–structure coupling and the fixture optimisation scheme adopted is feasible and can considerably shorten the test cycle and improve efficiency.