Mechanical Properties of Rubber Sheets Produced by Direct Molding of Ground Rubber Tire Powder

The so called “direct powder molding” is a compressions molding process which can be directly applied to ground rubber tire (GRT). This study shows that the GRT can be re-used to produce medium-size parts with good mechanical properties without any addition of virgin rubber. For rubber sheets prepared from the mechanically ground rubber tire (MGRT) and the cryogenically ground rubber tire (CGRT), the densities and crosslink densities of the rubber sheets increased with a decrease of the particle size of the waste tire powder. The tensile strength of the rubber sheets increased with the decreasing of the particle size for the two types of waste tire powder to 250 μm and 120 μm, respectively, and then became level. The moulding pressure had no effect on the densities, tensile strength or elongation at break of the rubber sheets. These results suggested that the effect of the particle size is important and is correlated with the mechanical properties of the rubber sheets produced by direct powder moulding technology. In general, the best mechanical properties were obtained with waste tire rubber with a size of about 250 μm for the rubber particles obtained from the mechanical grinding method of waste tire powdering.     

φ4m×60m回转窑轴线的测量

采用回转窑轴线测量仪,对河南省焦作岩鑫水泥有限责任公司φ4m×60m回转窑进行了轴线的测量。先后测量了托轮直径,轮带直径和顶间隙,在测量过程中还需要经纬仪进行参考面的建立。根据数据绘出了最终轴线水平直线度和垂直直线度的示意图。测量的原理和方法简单实用,可以得到比较高精度的数据。经过测量掌握了第一手数据,对于回转窑健康状况的认定和检测有非常重要的意义。     

Dual Friction Mode Textile‐Based Tire Cord Triboelectric Nanogenerator

As vehicles become smarter, an alternative power solution will become increasingly important for future vehicle development. With this context, a triboelectric nanogenerator (TENG) is proposed which fully sits on tires and consists of textile‐based tire materials. Both polydimethylsiloxane‐coated silver textile, serving as an external tire tread material, and nylon woven textile, serving as an internal tire cord material, performing as opposing triboelectric materials, are well adaptable for rolling tires. It is demonstrated that tire material‐based TENG performs at its maximum as it makes mutual contact with the road. The power generation property is characterized under different driving situations such as different tire rotation speeds and varying numbers of devices on the tires. The TENG demonstrates a maximum output voltage and a current of about 225 V and 42 µA, respectively, along with an output power of 0.5 mW at optimum load. The work offers the possibility to not only directly operate minute power‐consuming electronics but also collect power and store it while driving a vehicle.     

SS系列机车制动工况及轮对椭圆化在线监测的研究与实现

提出了一种ss系列机车制动工况及轮对椭圆化在线监测的研究,利用两个位移传感器实时检测制动器传动装置的位移量、车轮轮箍踏面的位移量,通过工控机计算以实现对制动工况中的缓解、制动情况、闸瓦磨损情况、轮箍磨损及轮对椭圆化情况的在线监测;以便于及时处理制动工况中的不良问题,保证行车的安全。通过MATLAB软件仿真了轮对椭圆化检测的变化曲线,验证了研究中对轮对椭圆化情况在线监测的可行性。     

飞机轮胎爆破模型初步研究

轮胎爆破是在航空事故中常见的一种现象,严重影响飞机的运行安全,因此需要对飞机轮胎爆破进行适航认证。飞机轮胎失效模式有多种,原因复杂。本文分析了轮胎爆破的适航审定基础,并对轮胎失效的危害模式进行了初步研究。     

橡胶复合材料结构大变形有限元分析

建立了一个橡胶复合材料结构有限元分析模型。在该模型中 ,考虑了轮胎变形的几何非线性、轮胎与地面和轮胎与轮辋的大变形非线性接触、轮胎材料的非均匀性和物理非线性及橡胶基复合材料的各向异性。此外 ,本文还利用该模型研制的有限元分析软件对全钢丝子午胎的变形轮廓进行了详细的分析。     

Traction performance of a pushed/pulled drive wheel

A comprehensive method for prediction of off-road driven wheel performance is presented, assuming a parabolic wheel–soil contact surface. The traction performance of a driven wheel is predicted for both driving and braking modes. Simulations show significant non-symmetry of the traction performance of the driving and braking wheels. The braking force is significantly greater than the traction force reached in the driving mode. In order to apply the suggested model for prediction of the traction performance of a 4WD vehicle, the load transfer effect was considered. Simulated traction performances of front and rear driven wheels differ significantly, due to the load transfer. In the driving mode, the rear driven wheel develops a net traction force greater than that of the front wheel. On the other hand, in the braking mode the front driven wheel develops a braking force significantly greater than that of the rear driven wheel due to a pushed/pulled force affected by the load transfer. The suggested model was successfully verified by the data reported in literature and by full-scale field experiments with a special wheel-testing device. The developed approach may improve the prediction of off-road multi-drive vehicle traction performance.     

Effects of central tire inflation systems on ride quality of agricultural vehicles

Instrumentation to collect ISO2631 ride data was installed on a CaseIH 8950 tractor equipped with a central tire inflation system (CTIS). Data were collected at two speeds on three courses representing degraded secondary roads, moderately rough fields, and the toughest of farming conditions. Reductions in tire pressures available with central tire inflation resulted in greater tire deflections and, consequently, a smoother ride. The CTIS improved the ride of the vehicle by 99% over properly inflated tires on average, and by 177% when not in resonance.     

A study of rubber flow in a mold during the tire shaping process using experiment and computer simulation

Automobile tires consist of more than ten layers, including tread, belt, carcass, sidewall, etc. The outermost layer, known as the tread, plays an important role during driving as it comes in direct contact with the road. This tread has grooves with complicated shapes, which are formed by a mold during the shaping process. When the tread rubber does not fill the mold properly, tire quality deteriorates crucially. As such, it is important to observe the flow of the tread rubber during the shaping process. To determine the flow of tread rubber in the mold, we conducted an experiment and computer simulation with white rubber strips inserted into specific areas of the tread. The white rubber strips showed detailed flow behavior of the tread rubber visually in the mold during the shaping process. No significant flows were observed for rubber in the central area of each block of the mold, but more changes were found near the edges of each block. The strips of rubber below the grooves exhibited more significant changes as they were pressed down by the protruding area of the mold. Moreover, there was no flow of rubber between blocks in the mold. This implies the profile design of the extruded tread should match the mold profile and the volume of each block. The experiment and simulation had similar results, and the observations of rubber flow in the mold using simulation proved to be highly useful.     

反式异戊橡胶合金改性溶聚丁苯橡胶/顺丁橡胶轿车胎面胶

研究了反式异戊橡胶合金(TPIR)的结晶性能、加工性能和力学性能及在轿车胎面胶溶聚丁苯橡胶/顺丁橡胶(SSBR/BR)中的应用.研究结果表明,与无定形SSBR和BR相比,TPIR生胶具有常温可结晶性,因此TPIR具有较高的格林强度.毛细管挤出行为研究结果表明,TPIR具有优异的挤出性能,挤出物外观光滑,挤出涨大比小.与SSBR/BR混炼胶相比,用TPIR改性后的SSBR/BR/TPIR混炼胶的格林强度与100%定伸应力随TPIR含量的增加而提高.经150℃硫化反应后制备的SSBR/BR/TPIR硫化胶物理机械性能优异:不仅耐湿滑性能、耐磨耗性能及压缩强度较对比胶提高,其伸张疲劳性能较对比胶提高4倍以上.透射电子显微镜(TEM)及填料分散仪表征结果表明,与SSBR/BR硫化胶相比,SSBR/BR/TPIR硫化胶的填料聚集体平均尺寸降低2μm,填料分散性显著改善.表明TPIR是一种应用于高性能轿车胎面胶的理想胶料.