大容量UPS电源车厢体骨架改进前后强度对比分析

大容量UPS电源车在首次设计制作中,发生骨架强度不够、厢体变形的情况,在对厢体骨架进行加固后,厢体再未发现变形情况,针对此次厢体变形整改情况建立加强前和加强后厢体骨架模型,运用ANSYSWorkbench对厢体骨架进行预应力模态分析,通过分析有限元仿真结果,对比厢体骨架在方案改进前后的应力和应变,得出厢体改进的可行性....     

隧道衬砌结构裂损机理及定量评估

隧道衬砌裂损影响衬砌结构的整体稳定性,并易引起渗漏水病害、基床病害和复合型病害等隧道病害,降低衬砌结构的耐久性和安全性.基于衬砌裂损的力学机理分析,将隧道衬砌混凝土裂缝发展过程分为6个阶段,给出每个阶段的状态描述,并针对引起衬砌裂损的隧道衬砌厚度不足及衬砌背后空洞两个影响因素进行深入研究,分别利用隧道衬砌的拉、剪应力集中系数进行计算,明确不同围岩条件下隧道衬砌厚度不足或衬砌背后空洞等因素与衬砌内部应力集中程度之间的内在联系,为进一步建立依据隧道衬砌检测结果进行隧道衬砌状态评估的评估体系提供了量化基础.     

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针对经典信号控制理论(Webster、HCM等)应用在拥挤交通环境下信号交叉口通行能力明显下降的问题,从分析交通参与者在拥挤与非拥挤交通环境下的驶离需求出发,以体现交通参与者的公平权益为目标,借用延误三角形方法推导了拥挤与非拥挤交通环境下交通参与者的总权益,并建立了两种交通环境下交通参与者权益与绿信比之间的关系模型。结果表明：在非拥挤交通环境下,Webster等经典信号控制理论兼顾了交通参与者的公平权益,在实践应用中取得了良好控制效果;而在拥挤交通环境下,单纯从交通量角度提出信号控制方案去解决或缓解交通拥挤会存在一定缺陷,需要综合考虑形成交通拥挤的其他因素来完善现有信号控制理论。     

开体泥驳半体主惯性轴的惯性矩计算方法

文中以1200m^3开体泥驳设计为例,依照《中国船级社钢质海船入级与建造规范》2006版中有关开体泥驳总纵强度校核的新规定,针对《规范》未给出开体泥驳半体剖面特性计算公式的情况,讨论了开体泥驳半体主惯性轴的惯性矩和转角的计算方法。     

滚动轮胎瞬态和稳态强迫响应分析

采用移动载荷的概念,分别推导了点力激励的响应及分布力激励的响应列式,计算了胎体上点在点载荷作用下的时间历程。为轮胎滚动模型提供基础。     

Moving towards more eco-efficient tourist transportation to a resort destination: The case of Whistler, British Columbia

Transportation is not only a key component of the tourism value chain, but it is also a critical management consideration in shaping tourism's environmental footprint. Transportation consumes the greatest portion of the energy used in the tourism system. Most of this consumption is associated with travel to and from the destination. Despite this situation, scant research has addressed ways in which destinations can play a role in reducing this energy use challenge. Strategies such as shifting visitors to more energy-efficient modes have the potential to improve the eco-efficiency of tourist transportation. Using a case study of transportation management options and visitor responses in Whistler, British Columbia, Canada, this paper examines visitor reactions to a range of transportation strategies designed to shift skiers from private to public modes of transport. Respondents completed an online survey employing both traditional and stated choice questioning methods to examine tourists' transportation choice behaviour. Long-haul tourists were the most likely to shift transport modes based on the management options offered to them. Destination management strategies for moving this target group to public modes of transportation are described.     

Excess commuting and modal choice

This paper reports results from research conducted to analyse the extent of excess commuting in Dublin, Ireland. The research differs from similar studies on excess commuting in two ways. First, a disaggregate modal choice analysis of excess commuting is undertaken for two time periods – 1991 and 2001. Second, sensitivity analysis is undertaken to explore the impact of changes in the density of the transport network for users of public and private transport. The results suggest that excess commuting is considerably greater for users of private transport implying the greater inefficiency of commuting associated with that mode. By way of contrast, capacity utilisation measures suggest the opposite indicating the difficulty of using these measures for policy-making. The results suggest also that the greater inter-mixing of jobs–housing functions has facilitated reductions in actual commuting costs as well as increasing the range of available trip possibilities over the study period. In terms of the sensitivity analysis, the results suggest that public transport users could achieve dramatic savings on their commute if the density of that network was increased considerably.     

分体组合式矩形顶管机关键技术探究——结合中铁装备地下停车场项目

为解决分体组合式矩形顶管机高精高效掘进难题,以中铁装备厂区地下停车场项目为依托,对矩形顶管机分体组合式结构适应性、位姿（位置与姿态）控制、组合式小刀盘开挖系统设计等关键技术展开研究： 1）提出新型组合连接形式,解决因设备组合带来的密封、管线联通等结构适应性问题; 2）创新盾体铰接结构,提出分体组合式顶管机复合位姿控制方法,即以纠偏油缸为主,双螺旋输送机互馈出渣为辅的协同纠偏策略,多刀盘转向转速控制与主机周向多点加压控制相结合的纠滚策略,实现浅覆土、零间距隧洞的高精度施工; 3）基于回归分析方法,探讨小刀盘扭矩系数随刀盘直径、刀盘布置位置的变化规律,建立直径3 m以下小刀盘扭矩系数的计算模型,为多刀盘系统驱动配置提供理论依据。     

城市居民出行方式距离曲线的研究与应用

利用城市居民出行调查的数据建立居民出行方式距离曲线,研究城市居民出行的规律,一方面能够了解城市内在因素时市民出行决策的影响,另一方面,将建立的居民出行方式距离曲线用于交通方式划分,可以弥补常用交通方式划分方法的不足。     

基于HyperWorks的汽车空气滤清器模态分析

乘用车空气滤清器的固有频率是一个重要的性能指标,需要满足特定的设计目标值。文章运用HyperWorks软件对某乘用车空气滤清器建立有限元模型,进行模态分析,获得固有频率,根据分析结果,提出改进措施,并对改进后的空气滤清器进行分析,确保其满足设计指标要求。