某车载油箱在随机振动环境下的疲劳寿命研究

目的 针对某车载油箱高周疲劳寿命难以预测问题，研究该设备在随机载荷环境下的疲劳寿命。方法 首先通过模态试验得到油箱固有频率及振型，然后利用Solidworks建立该车载油箱的仿真模型，在ANSYS Workbench软件中进行模态分析、随机振动分析、谐响应分析。最后利用ANSYS Workbench软件中的nCode SN Vibration (DesignLife)模块，在随机振动疲劳寿命频域分析法基础上，通过nCode模块中的Narrowband法进行油箱在多个加速度功率谱密度下的疲劳寿命研究。结果 该油箱在约束模态试验和仿真分析下所表现的动力学特性基本相同，油箱纵向为振动严酷方向。在已知加速度功率谱密度下，油箱疲劳寿命随低阶固有频率处功率谱密度幅值的增加而降低，但油箱薄弱部位始终保持不变。结论 建立的仿真模型准确，可为油箱优化设计及后续油箱疲劳试验提供参考。

Fatigue Life of a Vehicle Tank Under Random Vibration

The working environment of fuel tank is complex and changeable. The paper aims at the problem that it is difficult to predict the high cycle fatigue life of a vehicle fuel tank and to study the fatigue life of the equipment under random load environment. Firstly, the natural frequency and mode shape of vehicle tank are obtained by modal test, and the simulation model of the vehicle fuel tank is established by SolidWorks. Modal analysis, random vibration analysis and harmonic response analysis are carried out in ANSYS Workbench. Finally, through the nCode SN vibration (DesignLife) module of ANSYS Workbench software, the fatigue life of fuel tank under multiple acceleration power spectral density is studied by using the narrowband method of nCode module based on the frequency domain analysis method of random vibration fatigue life. The results show that the natural frequency and mode shape of modal test and simulation are basically the same, the longitudinal direction of the tank is severe. Fatigue life of the tank decreases with the increase of power spectral density amplitude at the lower natural frequency under known power spectral density spectrum, but the weak part of the tank remains unchanged. The established simulation model is accurate, this study can provide a reference for the optimization design of fuel tank and the subsequent fatigue test of fuel tank.