无水与充水塑料燃油箱的振动试验模态分析

Modal analysis of vibration test on plastic fuel tank with or without water

为设计轻量化汽车,在自行设计的测试台架上,对塑料燃油箱进行振动测试和模态分析。该测试台架具有足够的刚度,以测量得到有关频段内振动。在自由悬挂和安装两种状态下,在无水和不同充液量条件下,采用锤击法,再现燃油箱实际工作状态下的约束条件。以频响函数、模态频率和振型、模态相位共线性(MPC)和平均相位偏差(MPD)为指标,分析了边界条件对燃油箱振动特性的影响和充液量对安装状态下燃油箱的模态频率和振型等的影响。结果表明:随着充水量的增加,燃油箱的固有频率减小,振型也发生改变。

The vibration characteristics of plastic fuel tanks during the actual vehicle operation were measured in a test bench designed with modal analyses for a light-weight vehicle designing. The vibration modal of the fuel tank were compared and analyzed by using a hammering method for dry mode and the wet mode with different water contents under free suspension state and installation state. The test bench has sufficient rigidity to ensure measure the vibration characteristics of the fuel tank in the frequency band of interest, and to regenerate the constraints to the fuel tank in a actual running vehicle. The influence of boundary conditions on fuel tank vibration characteristics was analyzed with the norms of frequency response function, modal frequency and vibration mode, modal phase collinearity(MPC) and mean phase deviation(MPD). And the influence of the liquid filling amount on the modal frequency and vibration mode of the fuel tank in the installed state was focused on analysis. The research results show that as the water filling increases, the natural frequency of the fuel tank decreases with a changing vibration mode.