子午胎的固有频率预报

一定充气压力下, 子午胎的固有频率是由其材料和结构本身确定的。鉴于橡胶材料的粘弹性性质, 本文中以胎体为弹性基础、把子午胎模拟成一个胎面层具有粘弹性的圆环弹性基础模型, 并在此模型的基础上建立频率方程。本模型预报出的频率值能与实验值吻合。     

The “intelligent tire” utilizing passive SAW sensorsmeasurement of tire friction

The term “intelligent tire” describes tires equipped with sensor systems to monitor thermal and mechanical parameters while driving. Information about temperature, tire pressure, tread wear, etc., is collected and used for car operation and maintenance support. The contact between tire and road surface is a key parameter when characterizing the ability to accelerate, decelerate and steer a vehicle, therefore making contact monitoring important for modern car control systems. Following numerous previous theoretical works, the friction coefficient can be measured by evaluating the mechanical strain in the tire surface contacting the road-utilizing the deformation of the tread elements. A new monitoring method using passive radio requestable SAW sensors is presented. The principle, measurement setup and experimental results are shown     

基于LuGre摩擦模型的轮胎多边形磨损机理分析

多边形磨损是汽车轮胎磨损研究中的一个新课题,具有重要的理论价值和研究意义。考虑轮胎接地磨擦的非线性特性,建立了基于LuGre摩擦模型的轮胎多边形磨损的动力学模型。通过仿真给出了能够引起自激振动的车速和轮胎初始前束角范围。这些结果为减小或消除轮胎的自激振动提供了理论依据。     

子午线轮胎静负荷实验的有限元模拟

建立了一种子午线轮胎的三维非线性有限元模型,来模拟子午线轮胎的静负荷试验。模型中考虑了橡胶材料的非线性和不可压缩性、帘线-橡胶复合材料的各向异性、轮胎大变形导致的几何非线性以及轮胎与轮辋、轮胎与路面的接触非线性边界条件。提出了一种单元重叠技术,通过重叠不可压缩橡胶单元和描述帘线的单元来模拟帘线-橡胶复合材料,这种单元重叠技术产生的轮胎模型比正交各向异性模型计算过程更稳定。通过有限元分析,得到了子午线轮胎在充气压力和静负荷作用下的变形和应力分布情况以及接地区的压力分布情况,并将计算结果与试验结果进行了比较,两者吻合得很好。     

Baseline rolling resistance for tires’ on-road fuel efficiency using finite element modeling

Calculation of truck tires rolling resistance, using the finite element method and considering variables such as incompressible visco-hyperelastic rubber materials, accurate tire geometry and steady temperature distribution, is presented. The model was validated using experimentally measured contact area and contact stresses. Rolling resistance was calculated for three values of axle load, tire inflation pressure, temperature and speed. In addition, regression analysis was used to propose a mathematical expression for predicting rolling resistance as a function of the considered variables. Finally, the contribution of tire’s rubber components to the internal energy was quantified, and it was found that sidewall and subtread were the most relevant. The results of this study will help differentiate the contribution of pavement parameters, such as mean profile depth and international roughness index, to fuel efficiency.     

大扁平比胎侧解析刚度建模及轮胎动力学分析EI北大核心CSCD

针对重载轮胎大扁平比结构建模问题,从动力学建模、实验模态分析、结构参数辨识等方面,基于解析弹性基础的欧拉梁模型,对重载轮胎的柔性胎体和大扁平比胎侧曲梁的低频动力学特性开展研究,建立了考虑充气预紧力的欧拉梁胎体模型,利用实验模态方法,探究了不同充气压力下的柔性胎体振动特性;考虑胎侧曲梁预紧力弦效应和结构弯曲效应,建立了大扁平比胎侧曲梁解析刚度模型;基于模态测试结果,进行柔性胎体与解析胎侧结构参数辨识。研究结果表明:在0~180 Hz频率范围内,重载轮胎以结构周向弯曲振动为主,可利用基于弹性基础的柔性梁模型表征;大扁平比胎侧曲梁的解析刚度与胎侧的几何、结构和充气压力参数直接相关;轮胎充气压力影响柔性胎体梁的轴向预紧力和胎侧的弦刚度,进而影响轮胎弯曲振动特性。     

Application of Statistical Techniques and Neural Networks in Condition‐Based Maintenance

In this paper, we have evaluated five prediction approaches from two disciplines for condition‐based maintenance. It also includes a case study for vehicle tire pressure monitoring as an example application. Main focus of this paper is on two widely used areas in prediction: (i) statistics, (ii) neural networks. It is well known that these two areas have wide applications in forecasting. Statistical and neural network techniques are very powerful for predicting the future states based on current and previous states of the system or subsystem. Application of ARAR and Holt‐Winters (HW) in CBM has been presented from the statistics point of view. On the other hand, application of focused time delay, linear predictor, and backpropagation neural network has also been presented to prove the robustness of statistical approaches. Paper presents detailed comparative simulation study to show the suitability and feasibility of all the techniques. We assumed that the sensors are directly mounted on tires externally and report the current tire pressure to control or analysis. The control unit performs tire pressure analysis and reports the decision to operator or intended group about current pressure as well as the impending pressure conditions. Finally, investigation ends with conclusion that HW is best suited among these five approaches for tire pressure prediction and could be useful to design a CBM application for any system. Copyright © 2012 John Wiley & Sons, Ltd.     

轮胎硫化过程的数值模拟技术

把轮胎硫化热传导作为轴对称问题处理,从用热流密度表示的轴对称问题的有热源的非稳态热传导方程出发,建立了复合材料轴对称结构热传导分析有限元列式,进而结合轮胎硫化生热机理及变化的轮胎硫化加温历程研制了一个较全面地考虑胎硫化过程复杂性的有限元分析软件。用该软件对某轮胎的硫化过程进行了仿真计算,得到了一系列的数值计算结果。可以看出这些数值计算结果是符合实际的。     

遗传算法在轮胎结构多目标优化设计中的应用

在轮胎结构设计中应用一种基于共享小生境技术的遗传算法(简称Pareto GA),用来求解多目标优化问题的Pareto最优解集合。在综合考虑轮胎带束层的耐久性和轮胎重量的基础上,通过三维有限元分析和室内耐久性试验建立了优化轮胎带束层的数学模型,采用Pareto遗传算法对该数学模型进行求解,获得了分散性很好的Pareto最优解集合。为了检验优化的效果,应用三维有限元分析技术,对优化胎与原胎进行了分析与对比。结果表明,该优化过程达到了预期的目的。     

基于准则法的大型高压釜的优化设计方法

高压釜是压力精炼的核心部件,该文以一典型的压力精炼用大型高压釜优化设计为例给出一种基于有限元模拟结果和准则法的大型高压釜优化设计方法。首先给出一压力精炼用大型高压釜设计参数和技术指标,以重量最小化为目标,建立高压釜优化设计的数学模型;其次应用前处理软件Hypermesh和有限元软件Abaqus建立高压釜的三维有限元模型;然后基于满应力法和高压釜结构及承受载荷特点,构造优化算法,并应用构造的优化算法对高压釜进行优化设计;最后对设计的高压釜进行安全评定、模态分析和稳定性分析。安全评定结果表明高压釜各部件满足安全需要,模态分析结果表明高压釜动力特性能够满足设计要求,稳定性分析表明在承受意外附加载荷情况下设计的高压釜不会发生整体失稳。     

A Lagrangian cell‐centred finite volume method for metal forming simulation

The current article presents a Lagrangian cell‐centred finite volume solution methodology for simulation of metal forming processes. Details are given of the mathematical model in updated Lagrangian form, where a hyperelastoplastic J₂ constitutive relation has been employed. The cell‐centred finite volume discretisation is described, where a modified discretised is proposed to alleviate erroneous hydrostatic pressure oscillations; an outline of the memory efficient segregated solution procedure is given. The accuracy and order of accuracy of the method are examined on a number of 2‐D and 3‐D elastoplastic benchmark test cases, where good agreement with available analytical and finite element solutions is achieved. Copyright © 2016 John Wiley & Sons, Ltd.     

基于胎压的静态载重测量技术研究

研究了车辆胎压与载重的相关机理,通过测量轮胎内的气压变化间接测出汽车载重。对载重与受力模型进行了分析,并通过测量实验以及误差分析验证了所提出的模型的有效性和实用性。依据提出的测量方法,设计了一种基于胎压的新型数字式便携载重测量仪。该测量仪主要由便携式控制显示终端和压力变送器组成。实验测试结果表明,该测量仪测量精度较高、成本低、体积小、携带方便,适用于各种轮胎车辆的载重测量。     

A System to Measure Both Inner and Outer Car Tire Temperatures “in situ”

In the paper, a system for the complex analysis of the internal and external tire temperatures and pressure of sporty tires is presented. Tests were performed on the test circuit of a tire producer. The CTPA 05 measuring system (complex temperature-pressure analyzer) enables simultaneous measurements of the internal temperature and pressure in a passenger or sports tire. The experimentalist determines that the CTPA 05 can be used to measure independently the external temperature of the overcoat on the front wheel driving tires at three points. Measurements of both the internal tire temperature and pressure, as well as of the external tire temperature, are collected together with GPS (global position system) data. The system of measurement is fully automatic and contactless. The obtained results are in very good agreement with those obtained by independent methods.     

Modelling and joint monitoring of input and output of systems with arbitrary order autoregressive disturbance

Considerable studies have been done on modelling and joint monitoring of input and output of systems with autoregressive moving average (ARMA) disturbance. Most of these studies focus on systems with ARMA (1, 1) disturbance. However, many kinds of systems are not conform to ARMA(1, 1) disturbance. Motivated by the fact that an autoregressive (AR) model with high order can be implemented to approximate the stationary ARMA model at any precision, a new generic model and a joint monitoring scheme of systems with arbitrary order AR(p) disturbance are developed. A minimum mean squared error (MMSE) controller with arbitrary order AR disturbance is designed to reduce the system variability. The mathematical expectation and average run length of MMSE-controlled outputs are derived. A new joint chart for monitoring the input and output simultaneously is explored. Two out-of-control rules for the joint monitoring chart are developed. The monitoring performances of the input chart, the output chart and the joint monitoring chart are also discussed. The results of simulation experiments and case studies validate the effectiveness of the developed model and joint monitoring chart.     

Discrete modeling of sand–tire mixture considering grain-scale deformability

Mixing sand or soil with small pieces of tire is common practice in civil engineering applications. Although the properties of the soil are changed, it is environmentally friendly and sometimes economical. Nevertheless, the mechanical behavior of such mixtures is still not fully understood and more numerical investigations are required. This paper presents a novel approach for the modeling of sand–tire mixtures based on the discrete element method. The sand grains are represented by rigid agglomerates whereas the tire grains are represented by deformable agglomerates. The approach considers both grain shape and deformability. The micromechanical parameters of the contact law are calibrated based on experimental results from the literature. The effects of tire content and confining pressure on the stress–strain response are investigated in detail by performing numerical triaxial compression tests. The main results indicate that both strength and stiffness of the samples decrease with increasing tire content. A tire contact of 40% is identified as the boundary between rubber-like and sand-like behavior.     

轮胎模具花纹造型设计关键技术

轮胎花纹设计是轮胎造型设计中的技术难题,通过分析轮胎花纹的造型过程,归纳出轮胎模具造型设计的关键步骤,并给出具体的解决方案。详细分析了平面二维花纹向轮胎表面映射的关键技术,建立了映射的原理,并给出了具体的算法。对花纹直壁面生成和花纹沟槽构造等步骤也提出了相应的解决思路。造型结果显示该方法可以有效地构造轮胎花纹的形状,效果明显。     

Sequentially Generated Second Order Quasi D-Optimal Designs for Experiments With Mixture and Process Variables

Second order designs for experiments with mixture and process variables are proposed. They are constructed on the basis of continuous D-optimal designs by use of a three-stage procedure for sequentially generating optimal designs. The determinants of the information matrices of the designs obtained are very near to those of continuous D-optimal designs. Tables of discrete quasi D-optimal designs for q + r ≤ 7 are given, where q is the number of mixture components and r is the number of process variables. The experimenter can choose the number of trials N within the interval k ≤ N ≤ min(2k, k + 20), where k is the number of model coefficients. An application of the proposed designs in an investigation of truck tire properties is given.     

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。     

轮胎非线性对悬架系统振动影响的研究

建立轮胎线性和轮胎非线性的两组1／4车振动模型，并在Simulink中进行了仿真，仿真的结果表明：1、轮胎的非线性在高频区域对轮胎动位移和车身加速度有一定的抑制作用；2、轮胎非线性项系数ks的增大会使车身加速度的标准差下降，轮胎动位移的标准差增大；悬架动行程的变化则较为复杂，但在ks大于2230000N／m^2时增长的幅度较快，造成悬架的安全性下降；3、该振动系统存在着次共振和倍周期分岔等复杂的非线性动力学行为。     

不同载荷和初始气压下滚动轮胎稳态温度场的测试与有限元分析

进行了转鼓试验下滚动轮胎稳态温度场的测试;采用试验与计算相结合的方法验证了轮胎在转鼓试验中的实际滚动状态为自由滚动状态;根据解耦的分析思想,进行了转鼓试验下滚动轮胎稳态温度场的有限元分析。用实测的轮胎内部点的稳态温度对有限元的分析结果进行了验证,二者的一致性表明了该分析方法的可靠性。着重讨论了轮胎载荷、初始气压等因素对轮胎稳态温度场的影响。结果表明:随着载荷的增加,整个轮胎的温度场都呈上升的趋势;随着初始气压的增大,轮胎胎侧区域的温度场呈下降的趋势;初始气压对胎冠区域温度场的影响较小。