车轮双轴疲劳虚拟试验的胎-轮间载荷传递机理及模型

Fatigue life is the key point of lightweight design for automobile wheel. Since the biaxial fatigue test of the wheel is expensive and lasts long time, it is extremely urgent to develop a virtual biaxial fatigue testing method for wheel. The mechanism and discipline of non-linear loads transferring form between three-dimensional surface among the tire and wheel is unknown. In order to handle this issue, the project studies the load transfer mechanism between the wheel and tire. Then a model is established to describe the distribution of the load on the surface between the wheel and tire. Therefore, the wheel biaxial fatigue life can be predicted. Firstly, a tire model that can accurately reflect the tire and wheel load is established. By combining the simulation and experiment a modeling method is explored to calculate the interaction force between the tire and rim. With this method the ability in convergence of the computation can be improved, and also the cost is reduced. The loading condition of the biaxial fatigue test for automobile wheel is simulated. Then the characteristics of the coupling transfer in three directions between tire and wheel is studied. Biaxial fatigue life of the wheel can be evaluated through the critical plane multi-axial fatigue prediction method according to the stress calculation result for the wheel under biaxial load condition. The project can provide theory and simulation method for the virtual biaxial fatigue test. Besides, the possible achievement can reduce the cost of the wheel biaxial fatigue test, and also provide a more accurate basis for the wheel lightweight design.

汽车车轮轻量化设计疲劳寿命问题是关键，而车轮双轴疲劳试验价格昂贵，且周期长，因此发展车轮双轴疲劳虚拟试验方法十分迫切。针对胎-轮间三维曲面非线性载荷传递机理及规律不明对双轴疲劳虚拟试验的制约等问题，本项目将研究胎-轮间载荷传递机理并在此基础上建立胎-轮间曲面分布载荷模型，进而实现车轮双轴疲劳虚拟试验寿命预测。首先建立可准确反映轮胎与车轮间载荷的轮胎模型；考虑胎与轮间非线性摩擦力的影响，通过仿真与实验相结合，探索既能准确计算轮胎与轮辋间相互作用力又能提高计算收敛性、降低计算量的建模方法；模拟汽车车轮双轴疲劳试验时加载工况，通过仿真研究车轮双轴向动态变载作用下的胎－轮间三向耦合传递特性；基于双轴载荷下车轮的应力计算结果，采用临界平面多轴疲劳预测方法评估车轮双轴疲劳寿命。本项目将为车轮双轴疲劳虚拟试验提供理论及仿真方法，其成果的应用可降低车轮双轴疲劳试验成本，并为车轮轻量化设计提供较准确的依据。

车轮双轴疲劳试验是将车轮径向疲劳试验和弯曲疲劳试验结合在一起，按照一定的加载程序，对车轮同时施加两个相互垂直的作用力，以模拟在道路上的实际运行工况，从而更加真实地评价车轮的疲劳可靠性。本项目针对车轮双轴疲劳试验缺乏完善仿真方法的问题，在轮胎模型建立、胎-轮间压力分布规律、胎-轮整体建模方法、车轮双轴疲劳试验仿真方法及车轮双轴疲劳寿命估算等方面开展了相关工作，提出了一套完整的车轮双轴疲劳试验仿真方案，解决了已有方法过于简化难以实质性指导工程设计的问题。. 本项目通过实验测试，获得了某型车轮以及轮胎的非线性材料属性，建立了可用于车轮双轴疲劳试验仿真的轮胎等效模型及轮胎-车轮整体模型，通过对车轮在不同径向载荷作用下的静态、动态应力测试，验证了轮胎-车轮整体模型的有效性；采用薄膜压力传感器，测试并分析了胎-轮间压力分布特点；对比分析了胎-轮接触面的不同处理方法对仿真结果的影响；建立了车轮双轴疲劳试验的台架模型，基于多刚体模型假设，获得车轮在双轴载荷谱中不同载荷作用下的侧倾角；基于车轮-轮胎弹性体模型，实现了车轮在双轴载荷作用下的应力应变分析；基于各载荷工况下的车轮应力分析结果以及多轴疲劳理论，获得了车轮在双轴载荷谱作用下的疲劳寿命。. 通过本项目的研究，在车轮进行双轴疲劳的台架试验前即可通过仿真确定其危险点的位置，预测其疲劳寿命，基于仿真结果可对车轮结构进行改进，提高其双轴疲劳试验一次性通过率，降低试验成本，加速新产品开发速度，为提高我国钢制车轮在国际市场的竞争力提供技术支持。