Numerical investigation of hydroplaning characteristics of three-dimensional patterned tire

Hydroplaning characteristics of patterned tire on wet road are investigated by making use of finite volume and finite element methods. A detailed 3-D patterned tire model is constructed by our in-house modeling program and the rainwater flow is considered as incompressible and inviscid. Meanwhile, the fluid–structure interaction between the highly complicated tire tread and the rainwater flow is effectively treated by the general coupling method. Through the numerical experiments, the rainwater flow drained through tire grooves, hydrodynamic pressure and contact force are investigated and compared with those of the three-grooved tire model.     

Dynamic load and inflation pressure effects on contact pressures of a forestry forwarder tire

A Trelleborg Twin 421 Mark II 600/55-26.5 steel-reinforced bias-ply forwarder drive tire at inflation pressures of 100 and 240 kPa and dynamic loads of 23.9 and 40 kN was used at 5% travel reduction on a firm clay soil. Effects of dynamic load and inflation pressure on soil–tire contact pressures were determined using six pressure transducers mounted on the tire tread. Three were mounted on the face of a lug and three at corresponding locations on the undertread. Contact angles increased with decreases in inflation pressure and increases in dynamic load. Contact pressures on a lug at the edge of the tire increased as dynamic load increased. Mean and peak pressures on the undertread generally were less than those on a lug. The peak pressures on a lug occurred forward of the axle in nearly all combinations of dynamic load, inflation pressure, and pressure sensor location, and peak pressures on the undertread occurred to the rear of the axle in most of the combinations. Ratios of the peak contact pressure to the inflation pressure ranged from 0 at the edge of the undertread for three combinations of dynamic load and inflation pressure to 8.39 for the pressure sensor on a lug, near the tire centerline, when the tire was underinflated. At constant dynamic load, net traction and tractive efficiency decreased as inflation pressure increased.     

一种非对称大型有限元方程组的有效分块波前解法

提出分块波前法求解非对称大型有限元方程组，该方法综合分块解法和波前法的优点，根据计算机容量和方程的阶数优化计算过程，以在经济效率和存储效率之间达到平衡。本文利用该方法求解了轮胎稳态滚动有限元方程组，表明该方法是有效、可靠的。     

一种变厚度的精化壳体理论及其应用

在Reddy型高阶壳体理论的基础上，采用沿壳体厚度方向的剪切应变呈抛物线分布并且能够满足在壳体的上下表面为零的假设，发展出了一种适合于对变厚度壳体进行非线性分析的方法。该方法利用Ritz原理得到问题的控制方程。通过对一种典型的变厚度壳体结构（子午线轮胎）的结构分析，该方法的计算结果与商用有限元软件的三维分析结果能够很好的吻合。表明了该方法的适用性和有效性。     

废轮胎回转窑中试热解炭的重金属离子吸附特性

对废轮胎回转窑中试热解炭的重金属离子Pb2＋、Cr3＋和Cr6＋吸附特性进行了研究，分析了溶液pH值、接触时间、吸附剂用量以及溶液初始浓度对重金属去除率的影响。结果表明，溶液pH值对热解炭的重金属去除率有显著影响，阳离子Pb2＋、Cr3＋的去除率随pH的增加而增大，在弱酸和中性环境中去除率接近100％；Cr6＋在强酸性溶液中被还原成为Cr3＋，经二次吸附，总Cr去除率可达99％以上；Pb2＋和Cr3＋的去除率随热解炭用量和吸附时间的增大而增加，热解炭用量和吸附时间有一个最佳值。Pb2＋和Cr3＋的吸附为单分子层吸附，可用Langnuir和两段Freundlich等温吸附式描述，Freundlich拟合指数表明，热解炭具有较好的吸附性能。经酸洗后的热解炭对Pb2＋的去除率变低。     

废轮胎热解油的成分分析及二次热解反应

对废轮胎在中试回转窑中进行中温热解(450~650℃)所得热解油进行了GC-MS研究。通过对热解油化学组成 的全面分析,讨论了轮胎热解反应,尤其是较高热解温度和较长气相停留时间下的二次热解反应途径。通过与不同反应器 的比较研究,进一步得出了微负压回转窑热解技术的反应特点,并为回转窑热解油的应用提供了重要参考依据。     

综合流动和传热的废轮胎回转窑热解模型

废轮胎在回转窑内的热解主要受到气-固相流动、传质和传热及化学反应动力参数等因素的影响。在对回转窑 内固体颗粒运动、传热传质进行分析的基础上,结合对轮胎热解反应动力学的研究,发展了综合流动、传热的废轮胎回转 窑热解模型,可计算得到回转窑内热解的温度分布、物料转化率、产物得率等。模型计算结果与试验结果吻合较好。     

Pore structure of pyrolyzed scrap tires

Internal structure of carbon black produced by pyrolysis (CBp) of rubber samples from the top and bottom parts of sidewall and tread of a passenger car tire was investigated in nitrogen flow at different temperatures. The pore structure (specific surface area, pore size distribution, and porosity) of CBp and commercial CB, was compared. The development of pore structure and the increase of the specific surface area were most intensive during the thermal decomposition at temperatures ranging from 300°C to 500°C. This is caused by the intensive release of volatiles during the pyrolysis. After the pyrolysis was finished, at temperatures above 500°C, further decomposition of solid matter was associated with a slight increase of the specific surface area. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

Sidewall-insert compound based on ZnO-treated aramid pulp fibers for run-flat tires

Abstract

To improve the endurance performance of run-flat tires by preventing the sidewall from folding at zero air pressure, a master batch of natural rubber and ZnO-treated aramid pulp (AP) is applied to the rubber sidewall-insert-layer compound. The mechanical, viscoelastic, and fatigue properties of the compounds are investigated by varying the AP content, and the endurance performance of actual run-flat tires is assessed. The results indicate that the mechanical properties are improved and the hysteresis is reduced as the AP content increased. The overall trend of the endurance times of the run-flat tires is consistent with the results of the DeMattia tests, constant-strain fatigue tests, and high-temperature tensile tests. The run-flat endurance time of the tire containing one part per hundred rubber (phr) of AP is superior to that of the tire containing 3 phr of AP because of the enhanced dispersion of the AP fibers.