轻型货车轮胎接地压力分布实测

利用自主开发的轮胎接地压力测试仪,进行了轻型货车不同花纹和不同使用年限轮胎,在不同轮胎胎压和不同负荷作用下,轮胎的接地压力分布规律测量。实测结果发现:轻型货车轮胎与路面的接触形状更接近于矩形;新胎比旧胎的接地压力要均匀些;轮胎胎压与平均接地压力、轮胎负荷与平均接地压力、轮胎负荷与有效接地面积基本上呈线性关系。     

胎面沟槽内异物对轮胎接地特性的影响

接地特性是影响轮胎磨损的重要因素。针对轮胎沟槽嵌入异物可能影响轮胎接地特性参数的问题,以205/55R16型子午线轮胎为研究对象,利用Abaqus软件构建3种不同胎面花纹的轮胎有限元模型,采用控制变量法对比分析静态工况下异物直径大小对胎面接地压力分布及接地面积的影响规律。研究结果表明,胎面接地处因异物与沟槽挤压形成了关于异物对称的空区域,且靠近胎肩一侧面积较大,减小了轮胎有效接地面积;随着异物直径增大,胎面平均接地压力与接地压力偏度值均呈非线性上升,影响程度排序依次为S型轮胎、Z型轮胎、纵沟轮胎,影响轮胎正常磨损。该结果可为进一步研究轮胎瞬态磨损和偏磨损提供参考。     

长大纵坡路段轮胎接地压力分布的研究

轮胎形式与长大纵坡对于沥青路面的影响难以通过目前的均布荷载的分析得出,从而会低估荷载对路面造成的损伤.为此,利用有限元软件建立载重子午线轮胎与纵坡路段路面结构耦合的有限元模型,分析不同坡度条件下的轮胎接地压力分布,并模拟车辆爬坡过程,分析一定坡度条件下车辆受不同牵引力作用的轮胎接地压力分布.结果表明,通过建立轮胎-路面耦合的有限元模型,在路面模型建立过程中通过设置纵坡进行长大纵坡段轮胎接地压力分布的研究,在长大纵坡条件下的行车荷载对于路面的作用力在切向以及法向上都呈现出非均布特征,数值也都大大高于标准胎压.在坡度为6％,考虑牵引力系数为0.5时,坡面切向接地压力最大值达到法向接地压力最大值的95％,即达到1.23 MPa.     

沥青路面结构有限元建模计算误差研究

建立轮胎接地形状分别为圆形和矩形两种沥青路面结构有限元模型,并对建模计算结果误差进行对比分析,并与HPDS设计程序计算结果进行比较。结果表明,沥青路面轮载接地形状对路表的影响大于面层层底和基层层底,对剪应力的影响比较大,但这些结果对HPDS设计的结果影响不大,基本接近,矩形形式的荷载结果更接近HPDS程序设计结果。说明轮胎接地形式在有限元分析中采用矩形形式是可行的。     

实测轻型货车轮载作用下沥青路面力学响应分析

作者利用自己实测的轮胎接地压力分布,用三维有限元方法分析了轻型货车不同轮胎,在不同胎压和不同负荷作用下,沥青路面结构层的力学响应。结果表明:实际的轮胎接地压力分布具有明显的非均匀性,且随轮胎的结构类型、花纹、胎压、负荷甚至使用年限的不同而有很大的差异。轻型货车对路面结构产生的应力响应不能忽视。     

外倾和侧偏联合作用下轮胎接地印迹研究

基于德国Daimler Chrysler研发的Dtire轮胎模型，对外倾和侧偏联合工况下轮胎接地印迹形状和接地压力分布进行了研究，旨在为提高轮胎的附着性能，改善车辆的操纵性能以及改善轮胎磨损寻找可行的途径。     

不同车型非均布轮载作用力对沥青路面结构应力影响的三维有限元分析

轮胎与路面的接地形状呈较明显的矩形，且随着轮胎负荷及胎压的不同，对路面的作用力也发生不规则变化，呈现出非均匀分布。本文采用三维有限元分析方法，对不同车辆及其轮载作用力的均匀和非均匀分布情形下沥青路面的力学响应进行了分析。     

重载沥青路面荷载图式研究

现场调查货车的轴重及胎压分布,发现两者之间存在一定的对应关系。改变轴重和胎压,用轮胎上涂油漆的方法测试了轮迹,发现轮迹由一个矩形加端部的两个小圆弧组成,轮胎接地压强和接地面积均随轴载的增加而增加,荷载中心距保持不变。结合轮迹测试以及轴重和胎压的现场调查,得到我国重载车辆轮迹各几何尺寸以及平均轮胎接地压强与轴重的对应关系。根据轴重与胎压的对应关系确定两者的合理组合,用压力传感器法测试了移动车辆的轮胎接地压力分布,发现在全轮迹范围内基本属于均匀分布。最后,根据测得的重载车辆轮迹及轮胎接地压力分布,得到了重载车辆荷载作用图式。     

沥青路面非均布荷载下层间接触条件不同时力学响应的三维有限元分析

轮胎与路面的接地形状呈较明显的矩形，且随着轮胎负荷及胎压的不同，对路面的作用力也发生不规则变化，呈现出非均匀分布。本文采用三维有限元分析方法，分析柔性基层和半刚性基层路面结构的层间接触条件不同时，在不同的车型荷栽及其不同的荷栽分布情形下路面结构应力响应的差异。分析结果显示，不同的层间接触条件会对沥青路面结构的力学响应产生很大的影响。     

基于胎面咬合与压力胶片技术的路面抗滑机理研究

为了给路面抗滑性能的评价提供参考,基于压力胶片技术高精度测量压强的特性,探究胎面咬合在抗滑性能中的作用,设计进行了制动条件下轮胎在路面主骨料颗粒上滚动的动态简化模拟试验。用钢珠钢板简化体系模拟路面主骨料,在不同的荷载条件下,用压力胶片测量轮胎和简化路面之间的压强。分析试验数据表明:并非随着骨料颗粒粒径增大,轮胎与路面的咬合效果越好,随着主骨料颗粒增大,应力集中的峰值减小,同时应力集中分布度指标的值也降低。试验表明:胎面咬合力的阻力作用在制动过程中影响很大。同时混合料中的大颗粒在抗滑性能上的表现为增加了咬合深度,但是在力学上的咬合效果不是更加显著,相比于大颗粒,4.75～9.5 mm骨料与轮胎有更好的咬合效果。此外,试验数据阐明了轮胎与路面制动接触过程中,主骨料颗粒先与轮胎接触的一侧对轮胎存在拉扯作用的接触力学规律。     

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.     

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.     

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.     

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...     

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.     

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.     

Numerical method for simulating tire rolling noise by the concept of periodically exciting contact force

For the numerical simulation of tire rolling noise, an important subject is the extraction of normal velocity data of the tire surface that are essential for the acoustic analysis. In the current study, a concept of periodically exciting contact force is introduced to effectively extract the tire normal velocity data. The ground contact pressure within contact patch that is obtained by the static tire contact analysis is periodically applied to the whole tread surface of stationary tire. The periodically exciting contact forces are sequentially applied with a time delay corresponding to the tire rolling speed. The tire vibration is analyzed by the mode superposition in the frequency domain, and the acoustic analysis is performed by commercial BEM code. The proposed method is illustrated through the numerical experiment of 3-D smooth tire model and verified from the comparison with experiment, and furthermore the acoustical responses are investigated to the tire rolling speed.     

An optical tire contact pressure test bench

An optical tire contact pressure test bench developed by the IMMa group is described. The measurement system is based on the frustration of total internal reflection (FTIR) of light. The test bench allows performing normal pressure distribution and patch contact shape measurements on passenger car tires. The system is based on the use of a laterally illuminated glass on which the tire leans. Between them a plastic interphase is located that will cause the FTIR of light. A video camera catches the formed shining image through the glass. The brightness level in each pixel of the image can be related to the existing normal pressure. The study of the contact patch provided by the bench makes it possible to characterize tire behaviour under different loading states, inflation pressure, tire defects and toe and camber angles. The bench incorporates a computerized load and control system of the tire operation parameters, an image acquisition module and a data acquisition system that allow monitoring and acting on the experimental variables of interest in the tests such as load on the tire and environmental conditions. A supporting mechanical system incorporated to the bench allows providing the tire with variable toe and camber angles. From the images obtained with this system, the maximum normal pressure points, total force, size and shape of the patch can be determined, which are related to the tire-use conditions. As an application example, results that show the patch size and shape under different load and tire inflation pressures are presented. A further application, which is the use of the system for the detection and study of defective tires is also presented.     

An optical tire contact pressure test bench

An optical tire contact pressure test bench developed by the IMMa group is described. The measurement system is based on the frustration of total internal reflection (FTIR) of light. The test bench allows performing normal pressure distribution and patch contact shape measurements on passenger car tires. The system is based on the use of a laterally illuminated glass on which the tire leans. Between them a plastic interphase is located that will cause the FTIR of light. A video camera catches the formed shining image through the glass. The brightness level in each pixel of the image can be related to the existing normal pressure. The study of the contact patch provided by the bench makes it possible to characterize tire behaviour under different loading states, inflation pressure, tire defects and toe and camber angles. The bench incorporates a computerized load and control system of the tire operation parameters, an image acquisition module and a data acquisition system that allow monitoring and acting on the experimental variables of interest in the tests such as load on the tire and environmental conditions. A supporting mechanical system incorporated to the bench allows providing the tire with variable toe and camber angles. From the images obtained with this system, the maximum normal pressure points, total force, size and shape of the patch can be determined, which are related to the tire-use conditions. As an application example, results that show the patch size and shape under different load and tire inflation pressures are presented. A further application, which is the use of the system for the detection and study of defective tires is also presented.