乘用车子午线轮胎泵浦噪声机理的实验-数值混合分析方法

汽车在中高速行驶(乘用车超50 km/h,卡车超80 km/h)时,轮胎噪声取代其他部分噪声成为行驶噪声的主声源。轮胎噪声产生机理主要分为三种:泵浦噪声、振动噪声以及空气动力学噪声。其中泵浦噪声与轮胎花纹设计有关,属于可设计噪声。如何确定声源的频谱特性,进而预测轮胎噪声仍然是一个难点问题。提出一种泵浦噪声源识别的实验-数值混合分析方法。其基本的假设是:花纹横沟在进入地面和离开地面时产生气流,花纹纵沟将该气流收集,在轮胎接地前端和后端辐射出噪声;该噪声的大小与轮胎和地面形成的声场有关,也和轮胎花纹的节距排列有关。所提出的方法包括雕刻花纹轮胎噪声测试、轮胎声场阻抗数值分析、以及声源辨识三部分;通过在频域反演噪声传播过程辨识不同横沟的声源;通过雕刻花纹轮胎进行了噪声实验验证,说明了本方法的有效性。     

轮胎花纹噪声及其降噪方法

从动力学观点阐述了花纹块和花纹槽的发生机理,对花纹块宽度和长度、花纹槽宽度、长度与走向、花纹条数、基本节距数、节距排列次序以及错位参数进行了分析,得出降低轮胎噪声的原理和方法.根据结构参数分析并结合模糊控制理论和遗传算法,提出了一种轮胎花纹结构参数进行优化的设计方法--模糊遗传算法.利用轮胎噪声仿真分析软件(TNS2002)和仿真优化软件(ODS002)进行轮胎花纹结构设计,达到了降低轮胎噪声的目的,同时也得到低噪声轮胎花纹结构方案.研究成果为低噪声轮胎花纹设计规范与方法提供了路径.     

轮胎横向花纹沟噪声影响因素的剖析

运用Abaqus对具有横向花纹沟的轮胎滚动进行有限元分析,提取不同速度、气压、载荷、摩擦系数条件下的轮胎花纹沟表面在轮胎接地过程中位移-时间的变形曲线。为分析横向花纹沟的泵吸噪声,建立单个横向花纹沟及其周围的空气域有限元模型,在沟表面加载位移-时间变形曲线,利用FSI方法分析速度、气压、载荷、摩擦系数等使用因素对横向花纹沟泵吸噪声的影响。结果表明：泵吸噪声随着速度和载荷的增大而增大;气压变化均会使泵吸噪声增大;而摩擦系数对泵吸噪声影响不明显。验证FSI方法分析轮胎泵吸噪声是可行的,对后续低噪声轮胎使用和花纹设计具有一定的指导作用。     

自适应免疫遗传算法在轮胎花纹节距参数优化中的研究

节距参数优化是低噪声轮胎花纹优化设计的关键环节,针对轮胎花纹节距参数优化寻优时易引发数据爆炸的特点,利用自适应免疫遗传算法(AIGA)的自适应策略和快速搜索能力对节距序列参数和节距比例参数进行优化分析,结果表明该算法的收敛性和效率较遗传算法和免疫遗传算法都有明显的提高,优化结果可降低轮胎花纹噪声水平,具有工程应用价值。     

基于MLE的滚动轮胎冲击振动噪声仿真分析

提出一种滚动轮胎冲击振动噪声预测的新方法。轮胎滚动接触引发的噪声是道路交通的一个重要课题,引发广泛关注,目前尚没有有效的分析预测方法。提出新方法包括用混合拉格朗日—欧拉描述法(Mixed Logrange Euler Method,MLE)分析大变形滚动接触结构的速度场、加速度场和接触变形。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。通过将轮胎花纹和胎冠整体三维建模,可以得到连续轮胎表面的加速度场。以参考空间中连续表面的加速度场作为声源,采用声学有限元方法得到滚动噪声的分布预测。实验和仿真结果对比证明本方法的可靠和准确,也证明1 000 Hz以下轮胎的滚动噪声主要是花纹的冲击振动引起的噪声。提出的方法为预测分析轮胎的滚动噪声开辟一条可行的道路。     

室内转鼓法中不同转鼓面对于轮胎噪声影响分析

通过采用室内转鼓法对在不同转鼓表面工况下的轮胎噪声进行测试,并对相同工况下不同实验室的测试结果进行对比分析。结果表明,在不同转鼓表面所测得的轮胎噪声在频谱上具有显著的差异,并且轮胎噪声的大小与转鼓面的粗糙程度正相关。在ISO 10844鼓面与钢制光滑鼓面工况下,轮胎噪声随着速度的增加呈现明显的线性增长趋势。在ISO 10844鼓面工况下不同轮胎的声功率差值在各频带内基本一致,并且表现出明显的随频率变化的趋势,说明该转鼓面的测试数据具有良好的稳定性。     

不同花纹轮胎噪声辐射特性

轮胎噪声是交通环境噪声的主要来源之一,也是汽车噪声的主要声源。用虚拟模型预测的方法对滚动轮胎的振动辐射噪声进行预测分析。通过对滚动轮胎施加路面简谐激励,获取滚动轮胎表面加速度响应并作为声学分析的边界条件。采用边界元的方法分析不同花纹形式的滚动轮胎在路面激励下振动辐射噪声特性,结果表明花纹形式直接影响着滚动轮胎振动辐射噪声的大小,胎面花纹质量越小,振动辐射噪声越大,研究结果具有工程应用价值。     

轮胎成型有限元仿真研究

研究了385/55R22.5HN809 全钢载重子午线轮胎的成型过程,并利用ABAQUS 软件,模拟了成型过程的主鼓部件贴合、辅助鼓部件贴合、半成品胎成型和花纹挤压成型4 个工况,得出了成品胎的材料分布图,接着将仿真得出的结构和实际轮胎的断面结构进行了对比分析,最后对胶料厚度的仿真结果进行了分析。结果表明:仿真结构和实际结构具有很好的一致性,可以为轮胎的结构设计和施工设计提供指导。模型中,采用广义Maxwell模型描述混炼胶的力学行为,采用Rebar模型模拟橡胶帘线复合材料。     

高等级子午线轮胎项目在桂林开工

由中国化工橡胶总公司投资31亿元的高等级子午线轮胎产业化项目10月18日在广西桂林开工兴建。该项目建设以全钢载重子午线轮胎、工程机械轮胎和乘用轮胎等为主导产品的轮胎产业化基地,基地建成后可实现年销售收入32亿元,利税6．2亿元。项目先期启动年产120万条全钢载重子午胎,建设期24个月。     

发动机边盖辐射噪声仿真预测及实验

采取仿真预测与实验测量相结合的方法对某款发动机左边盖结构噪声进行分析。用LMS Test.lab测得发动机左边盖振动加速度信号,以此作为激励,导入到Hypermesh中对左边盖进行有限元分析。提取表面振动速度频谱,作为发动机边盖噪声辐射边界条件,运用LMS Virtual. lab对其进行声学仿真,并对噪声辐射仿真结果进行分析。再通过B&K 3560 D型数据前端对左边盖噪声进行测量,用波束成形法对测量结果进行分析,与仿真结果进行对比验证,两者声功率曲线吻合。对左边盖结构进行改进,再对改进后的左边盖进行噪声测量,整体噪声级呈下降趋势,改进效果显著。对边盖结构噪声预测以及整个发动机的降噪有一定参考作用。     

Optimum shapes of tire‐treads for avoiding lateral slippage between tires and roads

Optimum design of tire‐tread sections is an important practical issue. However, useful study of the problem that can suggest a reliable guideline for determining the optimum tread sections had hardly been made in the past. The present paper describes a new analysis of the state of stresses in tire‐tread sections in contact with the road surface, taking special care of the boundary conditions. Based on the analysis, a method is proposed to determine the optimum tread shapes for avoiding lateral slippage between tires and roads. The displacement potential function formulation, an ideal mathematical model for the practical stress problems, has been used in conjunction with finite‐difference method of solution. For the present analysis, lateral slipping in absence of frictional resistance as well as the no‐slip conditions of the tire‐tread contact surface have been considered along with a large number of tread aspect ratios. The present computational approach proves to be a powerful tool for determining the optimum tread shapes for avoiding the lateral slippage of tire‐treads. Copyright © 2005 John Wiley & Sons, Ltd.     

On the pyrolysis kinetics of scrap automotive tires

Pyrolysis kinetics of scrap tires of passenger car and truck have been investigated thermogravimetrically under heating rates of 5, 10, 20 and 30K/min and temperature range 373-1273K in nitrogen. The results show that the initial reaction temperatures are 482-521K for the tire of passenger car and 458-511K for truck tire. Both tires exhibit similar behaviors that the initial reaction temperature decreases, but reaction range and reaction rate increase when heating rate is increased. The overall rate equation for each tire can be modeled satisfactorily by a simple one equation from which the kinetic parameters such as the activation energy (E), the pre-exponential factor (A), and the reaction order (n) of unreacted material based on Arrhenius form are determined using Friedman's method. The results show that two tires behave similarly and the average kinetic parameters of two tires are E = 147.95 +/- 0.21kJ/mol, A = (6.295 +/- 1.275)x10(10)min(-1), and n = 1.81 +/- 0.18. The predicted rate equations compare fairly well with the measured data.     

Determination of relative damage of asphalt pavement from reduced tire contact area

Considering the traditional contact area which is a full circular contact area without any tread, in the current pavement design procedure, is an extreme overestimation of contact area and hence extreme underestimation of the real contact stress. Since the relationship between the contact stress and pavement damage is not linear but exponential, even a trivial difference between tire contact areas leads to significant difference in terms of induced pavement damage. This study was conducted to quantify the relative damage caused by realistic tire–pavement contact area with respect to the full contact area. Therefore, permanent deformation profiles of different contact areas at three tire load groups were obtained using an in-house Rotary Compactor and Wheel Tracker equipment and the relative damage analyses were done between tires with and without tread from various aspects. These aspects include operational life reduction ratio, rutting rate, linear and nonlinear relative damage concepts. It was concluded that on average real tires with tread cause 57% reduction in the operational life. In average, real tires with tread induce 1.23 times more mm per cycle. Based on linear relative damage analysis, in average, real tires with tread are 2.6 times more damaging. Furthermore, nonlinear relative damage analyses indicate that real tires with tread induce about three times more rutting compared to the worn-out control tread.     

滚动汽车轮胎自激振动仿真及其影响因素分析

以高速行驶汽车产生的轮胎周向多边形磨损现象为背景,通过建立轮胎的有限元模型以及轮胎-路面的LuGre摩擦模型实现了汽车轮胎高速滚动过程有限元模型的建立,应用该模型进行了轮胎侧向自激振动的仿真分析及影响因素研究。仿真结果表明滚动汽车轮胎在一定条件下确实出现了侧向自激振动现象,它也是造成轮胎多边形磨损的原因之一。参数灵敏度分析表明：轮胎侧向自激振动随车速的增加先增加后减小,车速过低或过高时均不能形成自激振动;前束角与外倾角对自激振动的影响与 车速相似,两者都存在一个峰值点;另外,大载荷条件下,胎面自激振动会比较剧烈,轮胎的多边形磨损也比较严重。因此,为避免产生轮胎自激振动,减少轮胎多边形磨损,要将设计参数以及使用工况控制在合适的范围内     

考虑高阶剪切的轮胎Gough刚度模型

轮胎是一种帘线增强橡胶复合材料结构,Gough刚度是表征轮胎侧向变形与磨耗的一个重要参数,但缺乏理论推导。本文基于高阶剪切复合材料梁理论,研究子午线轮胎带束层角度对轮胎侧向变形的影响及Gough刚度的理论基础。在Fiala横梁模型的基础上,将轮胎简化为弹性基础上的复合材料梁。胎侧及胎面胶简化为弹性基础,带束和胎体简化为复合材料梁。考虑高阶剪切位移场及帘线-橡胶材料的各向异性,利用虚功原理建立模型方程,得到了复合材料梁在侧向载荷作用下的小挠度理论解,与有限元结果和已有文献结果对比验证了其合理性。算例分析表明,当胎体等效梁结构的高宽比固定时,对应Gough刚度极大值带束角度是固定的;不同的帘线模量和橡胶模量也会对Gough刚度极大值所对应的带束角度产生不同的影响;带束层厚度对Gough刚度极大值对应的带束角度影响较小。根据Gough刚度极大值准则得到了不同高宽比下的轮胎最佳带束角度,利用实际轮胎解剖结构进行了验证。本文提出的模型为子午线轮胎带束角度优选和磨耗设计提供了理论指导。      

Hydroplaning Analysis for Tire Rolling over Water Film with Various Thicknesses Using the LS-DYNA Fluid-Structure Interactive Scheme

Current work studies the transient hydroplaning behavior of 200 kPa inflated pneumatic radial tires with various types of tread patterns. Tires were numerically loaded with a quarter car weight of 4 kN, and then accelerated from rest rolling over a water film with a thickness of 5, 10 and 15 mm on top of a flat pavement. Tire structure is composed of outer rubber tread and inner fiber reinforcing composite layers. The Mooney-Rivlin constitutive law and the classical laminated theory (CLT) were, respectively, used to describe the mechanical behavior of rubber material and composite reinforcing layers. The tire hydroplaning phenomenon was analyzed by the commercial finite element code - LS-DYNA. The Arbitrary Lagrangian & Eulerian (ALE) formulation was adopted to depict the fluid-structure interaction (FSI) behavior. Three different tire tread patterns, i.e. the smooth (blank) tread pattern and the 9 and 18 mm wide longitudinally-grooved tread patterns, were constructed to perform the current transient hydroplaning analysis. Simulated dynamic normal contact force and hydroplaning velocity of tire with a prescribed smooth tread pattern were obtained. The computed results were in good agreement with the numerical and test results given by Okano, et al. (2001) for tire running over 10 mm thick water fluid film. In addition, dynamic contact force of a smooth tread pattern tire rolling on a dry flat pavement was also found to be close to the result reported by Nakajima, et al. (2000). In addition, the effect of fluid water layer thickness on the hydroplaning velocity and normal contact force for tires with smooth tread pattern and longitudinally-grooved tread patterns rolling on a wet roadway analyzed by the LS-DYNA code are reported and discussed.     

轮胎多边形磨损的发生机理及其影响因素分析

考虑轮胎接地磨擦的非线性特性,采用由能量法确定的胎面单元侧向刚度计算公式,建立了基于胎面侧向振动的轮胎多边形磨损动力学模型,探讨轮胎多边形磨损现象的发生机理,并通过数值仿真分析了车速、轮胎前束角和垂向载荷对轮胎磨损的影响。结果表明：轮胎多边形磨损为胎面均匀磨损和扰动磨损叠加引起的周向不均匀磨损,是一种典型的非线性自激振动现象,其发生与胎面的侧向振动有关;以李雅普诺夫稳定性理论为基础,指出轮胎的自激振动是一种由系统Hopf分岔引起的稳定周期振动现象;高速、较大的前束角和超载是导致轮胎产生多边形磨损的可能原因。     

轮胎结构有限元分析应用于载重子午胎胎体反包高度的优选

载重子午胎胎体反包端点附近常常发生脱层或开裂破坏,这对轮胎的耐久性影响很大。本文作者应用轮胎结构有限元分析技术,对具有不同胎体反包高度的子午胎的关键区域中的应力分析参数进行了详细的分析,并据此对载重子午胎胎体反包高度进行了优选。     

Seismic base isolation using low-cost Scrap Tire Pads (STP)

This paper focuses on the experimental studies conducted on the development of no-cost seismic base isolation pads using scrap automobile tire pads (STP). The mechanical and dynamic properties of STP specimens made from different tire brands, with different number of layers, and orientations are evaluated experimentally. The tests are conducted using (a) axial compression tests, (b) lumped mass small displacement free vibration, and (c) large displacement (inclined plate and reverse-cyclic) static shear tests. The results of these STP tests are compared among themselves and against a commercially available laminated rubber bearing specimen. A general relationship has been proposed which formulates the stiffness differences between the two principal directions of rectangular pads. The paper includes three hypothetical design applications for the use of STPs. STPs are prepared by placing 18 cm × 20 cm cut tread sections layers of car tires on top each other. Larger size STPs can also be formed by placing longer strips of tread sections (integer multiples of tread width) side by side in alternating direction layers or using a woven structure. Test results have shown that the friction between tire layers is sufficient to keep layers intact. Although STP application cannot eliminate foundation-basement structural requirements, it presents advantages such as low-technology no-cost pad, weight reduction, ease of handling, simple shear stiffness adjustment by changing the number of layers, and environmental benefits by recycling scrap tires.