用于公路车-桥系统振动分析的精细化轮胎模型

Refined Tire Model for Analysis of Highway Vehicle-bridge System Vibration

为了解决当前公路车桥耦合振动模型中轮胎模型过于简化、车轮-路面接触力与桥梁响应计算结果不够精确的问题,提出了一种精细化轮胎模型。首先基于车辆橡胶轮胎的几何、力学特征,建立了径向弹簧力学模型并进行了理论推导;然后考虑轮胎与路面接触面的刚度分布特征和高速状况下轮胎的惯性力,提出了轮胎接触面分布刚度的计算方法,保证了轮胎接触面的变形协调和力学平衡关系。通过与现有研究结果进行对比,验证了轮胎模型的准确性和可靠性。研究结果表明:车辆轮胎惯性力引起的不平衡离心力会随车轮荷载和轮胎刚度的降低及车速的增加而增大,当车速达到60 km·h^(-1)时,不平衡离心力可能超过车轮荷载的10%并对轮胎的变形产生影响,进而改变车辆、桥梁2个子系统的接触关系,因此在车桥耦合振动分析中有必要考虑轮胎的质量及其产生的不平衡离心力;基于不同轮胎模型获得的接触力计算结果不同,从而引起车辆、桥梁动态响应计算结果的显著差异,且这种差异可能会随车速和车轮荷载的增加及路况的恶化而显著增大,因此实际运用中应尽可能选择精度较高的轮胎数值模型;采用不考虑面接触的单点模型可能明显高估车辆、桥梁的动态响应,而应用未考虑刚度重分布的改进弹性滚子模型在车速较高时会低估车辆的动态响应,与这2种模型相比,基于所提的刚度重分布模型进行车-桥系统振动分析时,其计算响应与实测结果更为接近,且对于桥梁动力冲击系数的估计更加准确。

This paper proposed a refined tire model to improve the applicability and accuracy of the numerical simulation on highway vehicle-bridge coupling vibration problems.Firstly,the radial spring tire model was established based on the typical truck tire’s main geometric and mechanical characteristics.Then,considering the distribution characteristics over the tire-road contact patch and the influence of the tire inertia force at high speed,the function of the contact patch’s distribution stiffness was developed per the principles of deformation coordination and mechanical equilibrium.Finally,the proposed tire model was verified by comparing it with some existing research.Results show that the unbalanced centrifugal force caused by tire inertia force can exceed 10%of the wheel load.It will increase with the decreasing wheel load,tire stiffness,and the increasing vehicle speed.As the unbalanced centrifugal force may further affect the tire behavior,the mass and dynamic characteristics of the truck tire should be fully considered.Different tire models can cause significant differences in the simulation results of the vehicle and bridge dynamic response.The difference will increase with higher vehicle speed,heavier wheel load and the deterioration of road roughness condition,so an appropriate tire numerical model should be selected if conditions permit.Using the single point contact model may overestimate the dynamic response of vehicles and bridges,while adopting the revised flexible roller contact model without considering the redistribution stiffness over the contact patch will underestimate the dynamic response of vehicles at high speed.Based on the proposed redistributive tire model,the simulated dynamic responses of the bridge-vehicle system are closer to the field data,which can predict a safer and more accurate impact factor(IM)for the bridge.