Mesh generation and hysteretic loss prediction of 3-D periodic patterned tire

This paper is concerned with the numerical prediction of the hysteretic loss-induced rolling resistance of 3-D periodic patterned tire. Elastomeric rubber compounds of rolling tire exhibit the hysteretic loss owing to the phase difference between stress- and strain-time responses. By virtue of this physical characteristic, the rolling resistance is considered as a pseudo-force resisting the tire rolling. The 3-D periodic patterned tire model is constructed by copying an 1-sector mesh in the circumferential direction, and strain cycles of each strain component are approximated by 3-D static tire contact analysis. According to the principal value of half strain amplitudes, the hysteretic loss is calculated in terms of the amplitude of the maximum principal strain and the loss modulus of rubber compound. The numerical results of 3-D periodic patterned tire are justified with the experimental data and compared with those of 3-D smooth tire.     

In-plane Dynamics of Tires on the Road Based on an Experimentally Verified Rolling Ring Model

The dynamic behavior of tires rolling on the road is predicted based on a ring model that is experimentally verified to well represent a real tire. The road contact is kinematically represented by two displacement constraints, one in radial and one in tangential direction. The displacement constraints are enforced via the receptance theory. The receptance matrix developed for the rolling tire is found to be Hermitian. Numerical results show that the natural (or eigen-) frequencies of the rolling tire with road contact are, as expected, higher than those of the tire with no contact. The influence of the rotating speed to the eigen-frquencies of the tire is also shown. Analytic expressions for the mode shapes of a rolling tire with ground contact are derived.     

In-plane Dynamics of Tires on the Road Based on an Experimentally Verified Rolling Ring Model

SUMMARY

The dynamic behavior of tires rolling on the road is predicted based on a ring model that is experimentally verified to well represent a real tire. The road contact is kinematically represented by two displacement constraints, one in radial and one in tangential direction. The displacement constraints are enforced via the receptance theory. The receptance matrix developed for the rolling tire is found to be Hermitian. Numerical results show that the natural (or eigen-) frequencies of the rolling tire with road contact are, as expected, higher than those of the tire with no contact. The influence of the rotating speed to the eigen-frquencies of the tire is also shown. Analytic expressions for the mode shapes of a rolling tire with ground contact are derived.     

载重子午轮胎与路面相互作用的分析

根据全钢载重子午线轮胎12.00R20的实际结构,考虑轮胎的几何非线性、材料非线性、接触非线性以及大变形等力学特性,应用有限元的方法建立轮胎的三维模型,橡胶材料采用Yeoh模型,橡胶-帘线复合材料采用加强筋模型,并通过轮胎径向刚度的测试验证了模型的有效性.在数值模拟中分析了轮胎在一定充气压力时,在不同垂直载荷和牵引速度的作用下,与地面在接触区域的变形情况、应力分布、摩擦应力分布等滚动接触规律.结果表明,轮胎与地面接触应力分布存在明显的非均匀性,轮胎的接地面积和地面总反力随着滚动速度的升高而增大.     

Index

A method is presented for the dynamic analysis of contact deformation for rolling tire on a road. The tire is modeled as an inextensible ring on elastic foundation with damping. Under known radial deflection, the ground contact region is predicted by solving simplified ring motion equation, treating ground contacting as a boundary condition. Furthermore, the effect of internal damping and rotating speed is analyzed on contact region.     

A Simple Analysis Method for Contact Deformation of Rolling Tire

A method is presented for the dynamic analysis of contact deformation for rolling tire on a road. The tire is modeled as an inextensible ring on elastic foundation with damping. Under known radial deflection, the ground contact region is predicted by solving simplified ring motion equation, treating ground contacting as a boundary condition. Furthermore, the effect of internal damping and rotating speed is analyzed on contact region.     

高速滚动汽车轮胎温度场的非稳态热分析

以试验数据为基础，分析了高速滚动轮胎温度场的非稳态热状况，应用最小二乘法对试验数据进行了拟合分析，建立了轮胎温升－时间历程关系式，并与理论计算公式作了对比，结果表明试验数据可靠；同时，分析了使用条件（速度、载荷、胎压及环境温度）对轮胎温升时间和大小的影响，结果表明，使用条件只影响轮胎温升大小，而不影响轮胎温升时间。用此方法建立了轮胎降温－时间历程关系式，分析了轮胎散热情况，分析表明温降时间也与使用条件无关。拟合关系式可用于初步预测轮胎温升及指导轮胎设计。     

汽车轮胎滚动阻力试验机测试方法分析

为了对汽车轮胎滚动阻力测试方案的可行性进行预先评估,基于检测设备的结构模型,提出了一种运用位移量对轮胎滚动阻力进行仿真分析的新方法。在简述滚动阻力有限元测试模型构建过程的基础上,通过改变轮胎的外部使用参数,分析传感器板在不同工况下位移场的分布情况,制定了设备的测试方案。以传感器的安装位置作为目标检测点,建立轮胎滚动阻力位移场与控制参数之间的关系曲线。最后将采集的数据经过平均滤波处理,与实验室的实测数据进行了趋势性对比。结果表明：采用该测试方法,轮胎滚动阻力随着轮胎负载和速度的增加而增大,随着气压的变大而减小;仿真结果和试验数据在相同工况下的变化趋势基本一致;该测试方法合理、可行。     

用于公路车-桥系统振动分析的精细化轮胎模型

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...     

轮胎滚动速度效应对轮胎侧偏动特性的影响

在利用试验模态参数建立轮胎侧偏非稳态模型基础上，本文重点分析了轮胎滚动速度效应对侧偏动特性的影响。解析模型计算结构的变化趋势和文献的试验研究结果一致。表明计入轮胎滚动所带来的速度对侧偏动特性的影响是不可忽略的，它会对不同速度下行驶汽车的操稳性及横向振动产生影响。滚动速度效应对轮胎侧偏特性影响的成功建械表明了利用模态参数对轮胎建模的优越性。     

轮胎在水平路面上的自由滚动接触分析

利用轮胎的模态参数直接对轮胎在水平路面上的滚动建立了便于解析计算的仿真模型。该模型可模拟轮胎稳态的滚动过程并可计算出不小同工况下的滚动特性、有效滚动半径、载荷与下沉量的关系以及印迹内变形和分布力。计算结果揭示了以往模型难以描述的微观现象,与以往文献的试验研究结果定性一致,充分显示了模型的合理性。     

Two-Dimensional Contact Area of a Pneumatic Tire Subjected to a Lateral Force

A mathematical model of a two-dimensional contact patch of pneumatic tires rolling over a rigid flat road surface at arbitrary slip and camber angles has been developed. The model is simple in concept, contains few parameters and is applicable to any tire simulation models. In addition to tire geometric parameters and vertical deflection, the carcass camber angle is introduced in the model. This angle is alone responsible for the asymmetric shape of the tire contact patch when the tire undergoes a lateral force. The computed contact patches agree well with the measured patches of an automotive tire at different slip and camber angles. Lastly, the influence of the contact patch geometry on the tire cornering and aligning properties has been discussed through a computational example. It has been shown that the effect of tire contact patch geometry on the steady state behavior is rather remarkable.     

汽车轮胎结构非线性有限元分析

本文综述了轮胎力学的发展历史与现状，阐明了轮胎结构分析的几各主要方法、研究内容及其优缺点，并重点介绍了在子午三维非线性有限元结构分析方面的工作，包括轮胎的充气，竖直加载、稳态滚动、滚动阻力及温度场分析，给出了相应的算例。由于采用一些新的方法和技术，考虑了更真实的轮胎材料模型，结构和载荷，使得分析更为有效、精确，分析结果可作为轮胎的设计，试验与改进的依据。     

高速滚动汽车轮胎稳态温度场分布的数值研究

建立了滚动轮胎热平衡状态下的简化传热数学模型。应用自行开发的传热和热弹性力学分析有限元软件对中型载货车用9．OO一20(12P．R)尼龙斜交胎进行了稳态温度场仿真计算，获得了胎体内部的稳态温度场分布。分析了轮眙的速度、几何结构参数及材料特性参数对轮胎最高温升的影响，通过回归分析建立了该轮胎速度与最高温升的经验计算公式。     

Prediction procedure for wear distribution of transient rolling tire

As a research method, finite element analysis (FEA) with ABAQUS can help researchers to study throughout the whole process of abnormal tire wear. For precise tread wear simulation, this paper introduces a tire finite element model building method. Then, the model is verified by comparing its simulation results with experiment data. Based on the verified model, tire high-speed rolling procedure is presented by combining steady-state transport analysis and dynamic analysis. To predict the wear distribution, micro tread wear calculation method is described. Finally, the wear prediction procedure of tread mesh evolving is introduced and tire polygonal wear pattern is simulated by this procedure.     

Vehicle Energy Dissipation Due to Road Roughness

Road roughness and surface texture are known to affect tire rolling resistance; however, little emphasis has been placed on the consequent changes in total vehicle energy dissipation due to road roughness. Thus, tire rolling resistance, in isolation from vehicle contributed losses such as dissipation in the suspension, appears to be a weakness in present evaluation procedures as they relate to fuel economy and pollution level testing: Recent work by Funfsinn and Korst has shown that substantial and measurable increases in energy losses occur for vehicles traveling on rough roads. The present investigation uses vehicle axle accelerations as a means of examining various road surfaces. Correlation with computer simulations has allowed the development of a deterministic road roughness model which permits the prediction of energy dissipation in both the tire and suspension as functions of road roughness, tire pressure, and vehicle speed. Comparison to the experiments of Korst and Funfsinn results in good agreement and shows that total rolling loss increases of up to 20 percent compared to ideal smooth roads are possible. The aerodynamic drag coefficient is also found to increase while driving on rough roads.     

Vehicle Energy Dissipation Due to Road Roughness

SUMMARY

Road roughness and surface texture are known to affect tire rolling resistance; however, little emphasis has been placed on the consequent changes in total vehicle energy dissipation due to road roughness. Thus, tire rolling resistance, in isolation from vehicle contributed losses such as dissipation in the suspension, appears to be a weakness in present evaluation procedures as they relate to fuel economy and pollution level testing: Recent work by Funfsinn and Korst has shown that substantial and measurable increases in energy losses occur for vehicles traveling on rough roads. The present investigation uses vehicle axle accelerations as a means of examining various road surfaces. Correlation with computer simulations has allowed the development of a deterministic road roughness model which permits the prediction of energy dissipation in both the tire and suspension as functions of road roughness, tire pressure, and vehicle speed. Comparison to the experiments of Korst and Funfsinn results in good agreement and shows that total rolling loss increases of up to 20 percent compared to ideal smooth roads are possible. The aerodynamic drag coefficient is also found to increase while driving on rough roads.     

Advanced Contact Mechanics–Road and Rail

The development of contact theories and numerical formula for various applications is a field which expands rapidly. This publication focuses on the rolling contact problem both for tire-road and wheel-rail contact. For the tire-road application a central problem is the modeling of the composite structure of the tire under internal pressure and axle load. One actual contact problem is the rolling on soft soil, which is discussed as the main application. In the wheel-rail case the contact area is much smaller and much more emphasis has been laid on the treatment of material changes, wear and creep phenomena. These approaches are discussed in detail as well as a more recent finite element formulation following the arbitrary Lagrange-Eulerian concept. Ideas about damage mechanisms finish the article.     

Advanced Contact Mechanics-Road and Rail

The development of contact theories and numerical formula for various applications is a field which expands rapidly. This publication focuses on the rolling contact problem both for tire-road and wheel-rail contact. For the tire-road application a central problem is the modeling of the composite structure of the tire under internal pressure and axle load. One actual contact problem is the rolling on soft soil, which is discussed as the main application. In the wheel-rail case the contact area is much smaller and much more emphasis has been laid on the treatment of material changes, wear and creep phenomena. These approaches are discussed in detail as well as a more recent finite element formulation following the arbitrary Lagrange-Eulerian concept. Ideas about damage mechanisms finish the article.     

山区高速公路坡面荷载的动态效应与实测研究

为了获取公路陡坡路段荷载对路面结构的动态效应,为理论计算分析和试验分析提供可靠的参数,利用自主开发的轮胎对地压力动态分布实时测量装置,进行了不同车型、不同载重、不同车速和不同纵坡条件下坡面轮胎接地压力的动态测量,得出了不同速度下坡面轮胎接地压力的分布及其变化规律。结果表明,高速运动状态下,重载货车轮胎接地形状近似于矩形,车速越高接地形状接近矩形的相似程度愈高;随着车速提高,接地压力的分布形式从凸起型分布逐渐向鞍型分布演变,接地压力峰值逐渐减小;运动状态下,车辆轮胎接地压力在行进方向上呈半正弦波分布,在横向上表现为非均匀分布。