矿用斜井人车所能通过的最小曲率半径的研究

矿用窄轨矿车和平巷人车可以看成是斜井人车的一种演变,其曲率半径的取值方法同斜井人车的曲率半径取值方法基本上是一致的,所以斜井人车所能通过的曲率半径的取值方法的研究有着重要的意义,对人车和窄轨矿车的设计、检测检验、研发也有着深远的影响。     

太阳能电动车动力传动系参数匹配的基础研究

总结并分析了太阳能电动车动力传动系布置方案.给出了动力传动系参数的匹配方法,并对相关参数的选择进行了分析.同时根据车辆功率跟随策略制定了动力传动系的控制策略,绘制了控制流程图.模拟实车试制了太阳能电动小车,根据试验测试结果,证明了理论研究的正确性,同时说明太阳能作为汽车能源是可行的.     

Hygrothermal effects on properties of highly conductive epoxy/graphite composites for applications as bipolar plates

The hygrothermal effects on mechanical, thermal, and electrical properties of highly conductive graphite-based epoxy composites were investigated. The highly conductive graphite-based epoxy composites were found to be suitable for applications as bipolar plates in proton exchange membrane (PEM) fuel cells. The hygrothermal aging experiments were designed to simulate the service conditions in PEM fuel cells. Specifically, the composite specimens were immersed in boiling water, aqueous sulphuric acid solution, and aqueous solution of hydrogen peroxide. The water uptake, changes in surface appearance and dimensions, glass transition behavior and thermal stability, and electrical and mechanical properties were evaluated. The water uptake at short time increased linearly with the square root of time as in linear Fickian diffusion. The presence of graphite significantly reduced both the rate and extent of water uptake. No discernible changes in specimen dimensions, surface appearance, and morphology of the composites were observed. The electrical conductivity and mechanical properties remained almost unchanged. The wet specimens showed slight reduction of glass transition temperature (T_g) due to plasticization of epoxy networks by absorbed water, while the re-dried specimens showed small increase of T_g. The composites maintained high electrical conductivity of about 300–500 S cm⁻¹ and good mechanical properties and showed thermal stability up to 350 °C.     

CFD simulation on performance of new type umbrella plate scrubber

A new type of umbrella plate scrubber was developed to address the pollution due to the dust, dioxide sulfur and other harmful gases, which were emitted from coal-burning boilers. The performance of the new device was studied through computational fluid dynamics（CFD） simulation and experiment methods. Initial work included experimental measurement of inlet-velocity, and gas phase simulation using Reynolds stress model（RSM）. After gas phase was converged, particles were injected from the inlet of the new device. Discrete phase model（DPM） was used for particle trajectories determination. The pressure drop and the collection efficiency of the new device were predicted through simulation. The simulation results show that the pressure drop of the new devices is 230-250 Pa and the efficiency is 84%-86%, with the inlet velocity equal to 10.6 m/s and the dust concentration ranging from 2 to 22 g/m3. The CFD simulation results of the new device show good agreement with experimental data. The relative error of the pressure drop and the efficiency is approximately 4% and 10% respectively. The results obtained both from the numerical simulation and from the experiment demonstrate that CFD simulation is an effective method for this type of study.     

质子交换膜燃料电池用铝合金双极板研究

以铝合金为基体材料的双极板,用电脑雕刻方法制作流场,采用碱性-酸性双镀液体系化学镀镍磷合金镀层.研究了热处理对镍磷合金镀层的表面形貌和耐腐蚀性的影响.结果表明,铝合金双极板经过化学镀镍磷合金后,可以满足质子交换膜燃料电池的性能要求.     

应用解析数值法反求热轧过程的传热边界条件

利用宝钢股份的实际生产数据,反求热轧过程的传热边界条件,并应用于板材热轧综合解析数值模型,提高模型计算精度。运用该模型预测轧制规程下各道次轧制温度和轧制力的变化情况。计算结果表明,模型计算得到的轧制力、温度与实测值吻合较好,反求参数与实际相符。     

铁路检修轨道车车体强度与局部应力集中分析

铁路检修轨道车是铁路巡检、救援、线路维修及施工作业用车辆。为保证一种新型轨道车在运行中有足够的刚度和强度,对其进行了有限元计算分析。计算结果显示,该轨道车车体钢结构多处存在严重的应力集中现象。对应力集中产生的原因进行了详细分析,并提出了改进方案,有效地解决了应力集中问题。     

四边简支压电层合板灵敏度分析的精确解

为了应用弹性力学中的Hamilton 正则方程研究压电材料的灵敏度系数问题,基于压电材料的H-R(Hellinger-Reissner) 变分原理,简要地导出Hamilton正则方程算子表达式,建立了四边简支板静力学控制方程。根据灵敏度定义,在静力学控制方程的基础上联立灵敏度控制方程,得到了增维的齐次压电材料静力响应和灵敏度系数混合控制方程。应用该方程可以同时求得压电层合板的力学、电学参量及其灵敏度。该算法过程简单、运算效率和稳定性好。数值算例结果与有限差分法的结果比较表明本文方法切实有效。      

余弦分布压力下矩形薄板的屈曲

针对不同支承条件,两对边受半余弦非线性分布压力下弹性矩形薄板的屈曲问题,进行了分析研究。对于只产生对称变形的矩形薄板,基于辛弹性力学的平面矩形域理论,给出了精确的面内应力分布。运用Galerkin法分析计算了半余弦分布压力下矩形薄板的屈曲载荷。根据各种不同支承矩形薄板弯曲的位移边界条件,借助于符号运算软件Maple,编写了相应的用户计算程序。对九种不同支承组合下的弹性矩形薄板进行了计算,得到了不同长宽比矩形薄板的屈曲载荷系数。通过与已有文献结果的比较表明,该文求解方法是有效和精确的。基于所给出的结果,可望为解决矩形薄板在非线性分布载荷下的屈曲分析提供一种新的研究方法。     

Coupled thermo-mechanical analysis of one-layered and multilayered plates

The paper considers a fully coupled thermo-mechanical analysis of one-layered and multilayered isotropic and composite plates. In the proposed analysis, the temperature is considered a primary variable as the displacement; it is therefore directly obtained from the model and this feature permits the temperature field to be evaluated through the thickness direction in three different cases: – static analysis with imposed temperature on the external surfaces; – static analysis of structures subjected to a mechanical load, with the possibility of considering the temperature field effects; – a free vibration problem, with the evaluation of the temperature field effects. In the first case, imposing a temperature at the top and bottom of the plate, the static response is given in term of displacements, stresses and temperature field; the proposed method is very promising if compared to a partially coupled thermo-mechanical analysis, where the temperature is only considered as an external load, and the temperature profile must be a priori defined: considering it linear through the thickness direction or calculating it by solving the Fourier heat conduction equation. In the second case, a mechanical load is applied. The fully coupled thermo-mechanical analysis gives smaller displacement values than those obtained with the pure mechanical analysis; the temperature effect is not considered in this latter approach. The third case is the free vibration problem. The fully coupled thermo-mechanical analysis permits the effect of the temperature field to be evaluated: larger frequencies are obtained with respect to the pure mechanical analysis. Carrera’s Unified Formulation is applied to obtain several refined models with orders of expansion in the thickness direction, from linear to fourth-order, for displacements and temperature. Both equivalent single layer and layer wise approaches are considered for the multilayered plates. At present, no benchmarks are available within the framework of a fully coupled theory. This work aims to fill this gap.