Tire wear by ablation

The transient temperature profile of a slipping tire is calculated by taking into account the frictional heating due to slip, temperature build-up due to hysteresis, convection and radiation loss into the air, and conduction cooling into the ground. Specific attention is directed to the calculation of tire surface temperature. Calculated surface temperature shows a value which may exceed the melting point of tread rubber. The phase change of the tread rubber at the surface leads to a particular wear mechanism. Wear of the tire is calculated for the transient process which occurs at the contact area between tire and ground.The governing equations for temperature profile and the associated wear process are solved numerically by a finite difference technique. Tire surface temperatures for different service conditions agree well with the available data for automobile tires. Tire wear data agree with those reported for airplane tires. The proposed wear model may be applicable to automobile tires when the service condition is severe.From the thermal analysis one can see the effect of surface properties of both tire and ground on the wear process. Other parameter studies provide some information about the effects of some important factors on tire wear.     

Evaluation of tire contact properties using nondestructive testing. Part 2: Experimental determination and fuzzy model of the contact parch in the static state

The paper presents the results of experimental determination of the contact parch area of various automobile tires in response to normal loading on the wheel and tire inflation pressure. The data are obtained for test bench conditions by visual processing of tread footprint. The test program covers five tire types of different manufacturers with different rubber blends. The experimental results are used to construct regression dependences and a multipurpose fuzzy model for determination of the contact parch area in response to loading on the wheel and tire inflation pressure.     

Numerical calculation of irregular tire wear caused by tread self-excited vibration and sensitivity analysis

Tire wear negatively affects vehicle safety and riding comfort. Abnormal wear is more dangerous and wears tires out more quickly. In this paper, numerical and sensitivity analyses of polygonal wear caused by unstable vibration are presented. The model used for this study was based on the works of Sueoka. Tread self-excited vibration was analyzed in a quantitative sense, which was qualitatively different from the work of Sueoka. Wear was plotted on tire circumference visually. The mechanism governing polygonal tire wear was investigated as that both the polygonal wear and the standing wave are caused by two types of tread vibrations that only differ in the extent of the tread vibration. Sensitivity analysis shows that decreases in tread mass and stiffness and increases in tread damping lead to noticeable reductions in tire wear. This information could help tire manufacturers produce tires that exhibit less wear caused by tread vibration.     

一种新的轮胎印痕测量及压力分布数据处理方案

介绍了一种基于压阻阵列成像方法的轮胎外圈表面花纹磨损检测技术,该技术通过检测轮胎在特定载荷下印痕的变化来估计轮胎的质量与使用寿命。在介绍测量原理的基础上,重点介绍了印痕图像处理技术与评价方法,针对轮胎花纹与地面接触产生的印痕图像确定边界与接触面积,研究了一种基于圆模板滚边的方法来获取图像外包络线的算法。研究表明该方法能有效处理凸壳与非凸壳图形,自动获取带凹槽图形的外包络区域,具有较好的鲁棒性和较高的精度。     

基于有限元方法的轮胎磨损特性研究

在基于有限元法的轮胎磨损性能评价方法的基础上,建立了205/55/R16型子午线轮胎2种胎面结构的有限元模型。使用ABAQUS软件的显式分析方法获得轮胎接地区域节点在汽车行驶过程9种工况下的法向反力和滑移速度,通过摩擦能量损失和磨损量之间的关系,求得轮胎在组合工况下行驶特定里程的磨损量。光面轮胎的磨损量明显小于花纹轮胎磨损量的仿真分析结果,说明了仿真分析方法的有效性。同时,通过对ABAQUS软件的二次开发,实现了轮胎接地区域摩擦能量损失率分布的实时描述。     

轮胎稳态运动学与六分力预报Ⅰ:理论与方法

提出一种新的轮胎运动学描述和六分力预报理论。滚动接触是汽车轮胎力学、轮轨动力学的核心问题,由于涉及刚体转动与有限变形,滚动接触运动学与动力学的描述与求解非常困难。用拉格朗日—欧拉混合描述法分析大变形滚动接触结构的速度场、加速度场和接触变形。以车轮定位角为卡尔丹角,用拉格朗日描述,得到了包含刚体转动和弹性变形的轮胎速度场。而接触区域的变形和受力用欧拉描述,通过欧拉网格和拉格朗日网格的信息传递,完成滚动结构动力学分析。所提出的理论可以退化到Fiala模型,并可以从理论上解释子午线轮胎的伪侧偏和伪侧倾现象。基于所建立的运动学理论和非线性有限元,建立轮胎六分力预报方法。针对某轿车子午线轮胎,分析轮胎接地面滑移速度、接地面积、接地压力、侧向剪力分布等随着侧偏角的变化规律,并研究该轮胎侧偏力和回正力矩随着胎面刚度和摩擦因数的参数敏感性。结果表明轮胎侧偏刚度和回正刚度主要受结构刚度控制,而峰值侧偏力和峰值回正力矩主要受摩擦因数控制。将利用所建立的方法和试验,探讨带束层结构对大规格子午线轮胎侧偏特性的影响规律,进一步验证所提出的理论和方法的正确性。所提出的理论和方法开辟了直接从轮胎设计预报轮胎六分力的新途径。     

Assessment of tire contact properties by nondestructive analysis. Part 1. The contact length in the region of adhesion at slow rolling velocities

The article discusses methods of nondestructive analysis for describing the contact interaction between the tire and the bearing surface. The problems of qualitative comparison of automobile tires are discussed. The contact length in the region of adhesion at individual points over the tire surface during rolling was selected as the criterion of assessment. The influence of load on the wheel and pressure in the tire on the contact length was explored in the region of adhesion at slow rolling velocities. A tire stand with a device to monitor the point of contact between the tire and the surface was used to obtain experimental data using methods of image processing. The results show different extents of wear of winter and race tires.     

Aerodynamic Characteristics of Isolated Loaded Tires with Different Tread Patterns:Experiment and Simulation

The current research of tire aerodynamics mainly focus on the isolated and simplified tread tire.Compared with the real complex pattern tire,the tread pattern structure and deformed profile of a loaded tire has a greatly influence on tire aerodynamic drag.However,the mechanisms of the isolated loaded tires with different tread patterns effects on the aerodynamic drag are subjects worthy of discussion.The purpose of this study is to experimentally and compu-tationally investigate the aerodynamic characteristics of three tires 185/65 R14 with different patterns under loaded.A wind tunnel test model was first established using three-dimensional(3D)printing with a ratio of 1∶1,and the pres-sure coefficients Cp of the three tires with different patterns are measured.The paper then conducted computational fluid dynamics(CFD)simulations for analyzing the pressure and flow characteristics.The accuracy of CFD simulation is verified by comparing the simulation results with the test results of pressure coefficients Cp,and they are of good consistency.While,the general analysis of pressure coefficients Cp results of the three tires indicates high-pressure area on the windward surface,and occurrence of low-pressure area on the leeward surface,the pressure coefficients Cp of all three tires decreased firstly and then increased along in the air flow direction.The authors finally analyzed the effect of tread patterns on the flow field around the tire and revealed the differences between flow characteristics and aerodynamic drag.The results show that,angle of tire lateral groove has great effect on the flow field characteristics such that;the more the angle of lateral groove agrees with the air flow direction,the less the flow separation and flow vortices,and a minimum observable aerodynamic drag.The research provides a guidance for the design of low aerodynamic drag tires,and helps to illustrate the impact of tire aerodynamics on the car body in the future.     

子午线轮胎的非自然平衡轮廓设计及性能分析

在分析现有子午线轮胎非自然平衡轮廓设计理论的基础上,以12.00R20和385/55R22.5两种规格载重子午线轮胎为研究对象,利用酒井秀男非自然平衡轮廓理论、Frank非自然平衡轮廓理论及新非自然平衡轮廓理论对胎体轮廓进行设计。利用有限元分析技术,从轮胎磨损、滚动阻力、抓地力等方面,对三种轮廓理论设计的两种规格轮胎的性能进行综合对比分析。结果表明：酒井秀男的设计理论适合于断面高宽比较大的轮胎;Frank的设计理论适合于断面高宽比较小的轮胎;新非自然平衡轮廓理论设计能够减小轮胎磨损,降低滚动阻力等;轮胎胎体轮廓设计对轮胎性能具有重要影响,尤其对滚动阻力具有显著影响,新非自然平衡轮廓设计理论为低滚阻轮胎设计提供了方向参考;新非自然平衡轮廓设计理论可解决轮胎性能间不相容的难题。     

CHARACTERIZATION OF EFFECTIVE TIRE CONTACT AREA FOR VARIOUS TREAD PATTERNS

The effective tire-pavement contact area affects the relative damage of asphalt pavement and should be incorporated in both mechanistic and empirical response analyses of pavements. A new machine called ROTOCOM Wheel Tracker (RCWT) was designed and fabricated to capture the effective tire contact area apart from slab compacting, and conducting simulative laboratory wheel tracking tests. The main focus of this paper is laboratory measurement of effective tire contact areas for various tread patterns. Seven tire treads were selected for the footprint image analyses at five tire loads and four tire inflation pressures. An image processing MATLAB-based program was coded to calculate the contact areas of the 280 imprints obtained from both sides of the RCWT. Factorial analysis indicated significant effects of tire tread, tire load, and inflation pressure on the resulting contact area. Comparison between effective and traditional contact areas indicated that the current pavement design procedure with traditional circular contact area extremely overestimates the actual tire-pavement contact area up to 92%.     

The influence of wheel/rail gap and rotating mechanism on dynamic performance of APM

The dynamics equations of Automatic passenger mover (APM) vehicle with the middle-guiding single-axle tire running gears were derived using linearized tire model, in which side force and rolling contact effect on running tire are taken account. A simulation model of APM vehicle based on Simulink environment was built using object-oriented programming technique, and the effects of contact statues between guiding tires and rail and different rotation modes on of curving performance and ride quality were studied. The simulation has shown that the preload force on guiding tires don’t improve curving performance but significantly worsen lateral ride quality, whereas the gap between guiding tires and rail will increase the running tires side force and guiding tires radial force on curve. The gap between guide tires and rail should be controlled between 0 and 5 mm on compromising the curving performance and ride quality of APM vehicle. The cornering force of the rotating mechanism above the springs mode is greater than that of the below mode, and decreases with the increase of the curve radius, which is unfavorable to the curve passing.     

冰面和干燥路面上轮胎侧偏特性的试验研究

采用自行研制开发的平台往复式轮胎力学静特性试验机,研究了两条规格和胶料性能相同但胎面花纹不同的子午线轮胎在干燥路面和冰面上的侧偏特性,并进行了对比分析。重点讨论了冰面温度、轮胎负荷、轮胎气压和胎面花纹等因素对侧偏特性的影响规律。结果表明:低温冰面上轮胎的侧偏特性与干燥路面上的轮胎相似,但胎面花纹对冰面轮胎的侧偏特性产生更明显影响;在允许范围内适当降低气压有利于轮胎的操纵稳定性。     

Method of Constructing a 3D Friction Map for a Rubber Tire Tread Sliding Over a Rough Surface

An experimental methodology for constructing a 3D friction map, which depends on normal pressure, sliding velocity, and temperature, for tire tread rubber has been presented. The methodology of constructing a 3D friction map is based on the principle of temperature–velocity superposition, which makes it possible to combine the obtained experimental data into one sculpted surface. Two types of the tread rubbers were investigated that are used in summer passenger tires and heavy-loaded all-metal tires. The results of analyzing the obtained 3D friction maps have been presented. The influence of normal pressure and sliding velocity to the amount and position of the values of coefficient of friction of the rubber sliding over the sandpaper surface with the specified abrasive grit has been considered.     

ADAMS在汽车轮胎动力学研究的应用

汽车轮胎的力学特性是优化轮胎设计,提高轮胎性能的重要依据。然而汽车轮胎的行驶条件的复杂多变,给轮胎的力学特性的掌握和计算带来不少困难。将ADAMS应用于汽车轮胎的动力学研究,可以利用软件来模拟汽车轮胎的各种行驶条件,并利用数学模型计算出汽车轮胎在各工况下的力学特性参数。通过这一过程,工程技术人员可以减少汽车轮胎设计过程中试制试验的轮次,从而达到降低轮胎试验成本,并优化轮胎设计的目的。     

湿滑状态下轮胎路面摩擦特性的数值分析方法

为研究湿滑状态下轮胎路面的摩擦特性,以胎面橡胶和沥青路面作为研究对象,利用谐波叠加法建立三维粗糙路面模型,采用“伪”流体动力轴承作用等效反映路面水膜“密封”作用,综合使用有限元软件ABAQUS和计算流体动力学软件Fluent得到湿滑状态下橡胶与路面滑动接触时的橡胶接触压力、滞后摩擦力及路面水膜承载力,由此形成了综合兼顾橡胶材料、接触压力、滑动速度、路面形貌和路面水膜等多因素的轮胎与湿路面摩擦特性的仿真方法。通过橡胶与干-湿路面摩擦特性的变化与公开的试验对比,证明本方法的合理性和可行性,并进一步分析滑动速度、接触压力和路面特征对湿滑状态下轮胎路面摩擦特性的影响规律。研究结果为轮胎和路面的抗湿滑性设计及优化提供理论依据。     

汽车轮胎磨损机理的研究

综合分析了汽车轮胎和路面间相互作用产生的磨损形式和磨损机理,以及研究轮胎磨损常采用的方法。运用摩擦学原理提出了轮胎磨损的分类形式,为正确预测正常工作条件下的轮胎磨损率提供了必要的基础知识。     

Shape design of a tire contour based on approximation model

The basic purpose of a tire is to enhance vehicle performances such as driving performance, rolling resistance, durability, ride comfort, noise, wear resistance, etc. by acting as a flexible cushion. To meet the demand for increased vehicle performances, the design method of a tire has advanced. This study proposes a structural design method for tire contour by considering both the tread contour and the sidewall contour, simultaneously. Existing studies of tire contour optimization have focused on the tread contour and the sidewall, separately. Durability, maneuverability and ride comfort are performances that are commonly investigated in tire contour design. Durability, maneuverability and ride comfort can be measured by the values of the strain energy density, tension and vertical stiffness, respectively. The optimization technique using a metamodel is introduced to maximize durability while satisfying the imposed constraints of tension and ride comfort. To achieve this, the responses defined in the optimization formulation are expressed mathematically in explicit form with respect to the design variables by using the kriging surrogate model, resulting in a simple optimization problem. Then, the simulated annealing algorithm is utilized to find the global optimum.     

[轮轨磨耗及预测]列车紧急制动过程中踏面温度分布及磨耗预测

列车紧急制动过程中踏面温度急剧升高导致车轮踏面的摩擦磨损机理与稳态运行时有显著差异。为了准确预测列车紧急制动过程中踏面磨耗,同时考虑踏面制动过程中车轮踏面与钢轨及闸瓦接触,基于有限元软件ABAQUS建立了踏面制动过程热机械耦合有限元模型,综合考虑制动温升对车轮踏面力学性能、硬度及摩擦因数的影响,仿真得到了紧急制动过程中车轮踏面上温度分布、硬度分布以及接触应力分布,并利用轮轨动力学软件UM得到了紧急制动过程中轮轨接触斑形状以及轮轨蠕滑区相对滑移分布,在此基础上结合Archard磨耗模型对单次紧急制动结束后的踏面磨损深度进行了定量预测。结果表明：对于制动初速度为130 km/h、160 km/h两种工况,踏面最高温度分别达到了397.0 ℃和485.9 ℃,踏面最大累积磨损深度分别为5.90 μm和7.43 μm,与踏面制动实验对比发现,预测结果与实验结果磨损位置及形貌分布趋势一致。     

飞翔智能轮胎的仿真设计

长期以来,由于轮胎而导致的各种问题频频出现,为此对汽车轮胎进行优化设计,以SolidWorks软件为三维建模平台,运用多传感技术对轮胎和路面情况进行实时监测,采用RFID射频技术标识和跟踪轮胎,使用机械传动方式控制轮胎的花纹形状和深度,能够实现轮胎的智能化,保障道路行车安全。项目组运用压力、温度传感器对轮胎内压强、温度进行检测,在轮胎中增加RFID电子标签对轮胎出厂信息,车辆轮胎匹配信息进行记录,在不同路况下,改变轮胎花纹,使轮胎的摩擦因数跟路面信息相适应。     

复杂花纹轮胎湿滑路面制动距离FEM仿真分析及评价

以205/55R16型子午线轮胎为研究对象,对配有ABS系统的汽车在湿滑路面上的制动距离进行了仿真研究。基于制动过程离散分析方法,使用有限元商业软件ABAQUS仿真研究了不同复杂胎面花纹及不同胎面材料轮胎在1.5mm深积水路面、各离散速度下的制动情况。然后根据各有限元仿真结果,使用相关分析方法,获得了轮胎的制动距离。仿真结果均与对应的试验结果趋势一致,证明了轮胎湿滑路面制动性能仿真评价方法的有效性。