MODIFICATION OF GEOMETRY AND TECHNOLOGY OF CYLINDRICAL WORMS

The objective of this research is to develop a new method of grinding process that can efficiently make concave profile of the worm thread smooth. The grinding is carried out using a wheel with curvature profile in the axial plane in the form of an arc of logarithmic spiral. The proposed method will provide maximum line of contact between the tool and the worm with minimum stress concentration at any point. The generating equation of the grinding tool profile and its arrangement with respect to the worm during thread grinding were determined.     

EPB盾构机刀盘开口模式与刀盘盘体结构耦合设计

以某地铁标段施工盾构为研究对象,针对EPB盾构机的刀盘的开口模式与盘体结构设计之间相互影响、耦合的特点,首先建立根据边界条件与三轴实验获得的岩土颗粒微观参数构建盾构刀盘与岩土相互作用的刀盘系统离散元数值模型,研究盾构刀盘开口率对刀盘挖掘过程的影响规律。在此基础上,建立基于渣土流动性的刀盘结构参数优化设计模型,在AWE下对刀盘的整体结构进行优化设计。研究结果表明:在某地质条件下,开口率为35%,中心开口占45%的刀盘挖掘效率较高且满足螺旋输送系统工作条件。     

基于NSGA-Ⅱ叉车轮边减速器优化设计

以叉车轮边减速器行星轮系为研究对象,在满足设计要求的前提下,以轮边减速器行星轮系齿圈直径最小,中心距最大和重合度最高为目标建立目标优化数学模型.运用改进的NSGA-Ⅱ对多目标优化并得到Pareto最优解集,利用多指标加权灰靶决策模型选择最优设计方案.优化结果表明：改进遗传算法的运用是可靠有效的,为以后产品优化设计提供新了的设计思路.     

Arriving Landscape

Staring through the window of a Chinese high speed train on my way home from Shenzhen to Wuhan, I saw landscapes framed by the context of the train; its windows, its acceleration. This frame with a speed of 300 km/h gives a new perception to the outside landscape, as the railway route itself creates new forms of political economy. The video installation “Arriving Landscape” is an experimental documentation of this experience, while also an observations of Chinese travelers’ experience inside. The video serves as a critical medium for both representation and research; what you see is equal to how you see, both inevitably associated with the development of the contemporary railway infrastructure, urban and rural development, speed and politics.     

基于模糊神经网络的铁路车辆热轴等级判别模型

判别模型。该模型选定了温升、列温升差、辆温升差3个特征作为输入量,4种热轴等级作为输出量,并利用125条模糊推理规则和学习算法对模糊神经网络进行训练,得到的模糊神经网络可作为专家系统对热轴进行判别。实例仿真结果表明:模糊神经网络热轴判别模型使得判别参数减少,判别科学化,且判别的一致率达到95%。     

起重机车轮与轴过盈连接可靠性设计和分析

通过计算分析起重机车轮与轴过盈连接的受力情况,利用可靠性联结方程,对此连接方式进行可靠性验证,从而得出过盈连接优先选用的配合。     

Physical,mental, emotional,and subjective workload components in train drivers

This study, using 12 train drivers on a high speed track and 11 drivers on a mountain track, tried to differentiate between the physical, emotional, mental, and subjective workload components imposed on the drivers during work. With the simultaneous recording and on-line analysis of heart rate and physical activity, the emotional component in terms of the so-called additional heart rate was separated from the physical component. Mental workload was calculated by the heart rate variability and by shifts in the T-wave amplitude of the ECG. Speed of the train, mode of driving, and stress of the situation were rated by two observers who accompanied the drivers in the cabin. During speeds up to l00km/h as compared to standstills no heart rate changes occurred, but with speeds from l00km/h up to 200 km/h heart rate decreased indicating a monotony effect. However, heart rate variability, and T-wave amplitude indicated higher mental load during driving in most speed categories. Starting the train and coming to a halt showed greater emotional workload as compared to moving. Observer ratings of stress and subjective ratings of stress by the drivers revealed several discrepancies. Discrepancies were also seen between workload as indicated by the physiological parameters, and corresponding stress ratings by the observers or by the drivers.     

Multi-route railroad blocking problem by improved model and ant colony algorithm in real world

In rail freight transportation, general merchandise freight cars may pass through many classification stations on their route from origin to destination. The Railroad Blocking Problem (RBP) is to reclassify inbound traffic from various origins in the classification stations and put them on outbound trains with the same or close destinations, the objective of the RBP is to minimize the total operating costs of delivering all traffic on the railway network while satisfying the resource and capacity constraints at the stations and the priority constraints for shipments. In this paper, we introduce a new mathematic model which can comprehensively describe the blocking strategy and various combinations of multi-route O–D pairs in large scale railway network. Furthermore, we propose an improved Ant Colony (AC) algorithm for RPB, and a computational experiment derived from the real life instances of coal heavy haul rail network in north China is given. Experimental results verified the validation of the model and effectiveness of the algorithm.