斗轮堆取料机的回转支承选型

大型回转支承的结构型式主要可分为点接触式和线接触式两大类。线接触式有单排及交叉滚柱式、交叉滚锥式、多排滚柱式等。其中三排滚柱式大型回转支承装置在斗轮堆取料机中应用最为广泛。     

回转支承的开发与使用

回转支承是用于工程机械、矿山机械、建筑机械以及其它机械中需要两部分相对回转运动的基础零件.它尺寸通常很大又类似于轴承,因此也有人把它称为大轴承.但它有着不同于常见轴承的特性:能同时承受很大的轴向力、径向力和倾翻力矩,一般为低速转动,采用齿轮传动.它在港口机械行业中也已得到广泛使用,如已用于门座起重机、固定式起重机、浮式起重机、堆料机、取料机、装船机、卸船机、轮胎式起重机等机械上. 1984年首次发布的JB 2300-84<回转支承型式、基本参数和技术要求>标准,以及在1999年修订的JB/T 2300-1999<回转支承>标准,现已是回转支承设计、选型与使用的基础标准,这两个标准均来源于1981年徐州回转支承公司引进的德国克虏伯HRE公司回转支承专有制造技术.     

港口门机回转支承的故障预防

港口门机的回转支承结构目前主要有两种,即转盘式和转柱式.由于制造方便、运转平稳、整机结构简单美观,目前大多数门机,特别是大吨位门机主要采用转盘式回转支承结构形式.回转支承作为门机固定结构与回旋转结构相联接的一个重要部件,其工作状态直接影响门机的安全和正常使用.     

门机回转支承故障实时检测与诊断系统

针对港口门机回转支承装置的故障诊断问题，设计了一套故障实时检测与诊断系统。该系统采用振动诊断分析方法，以LabView为开发平台，应用时域分析、频域分析、相关分析以及小波分析等方法判断回转支承的故障原因，实践证明具有较好的诊断效果。     

振动对起重机回转支承部件强度的影响分析

回转支承在回转过程中不可避免地将产生振动 ,由振动所带来的冲击会影响部件的强度。根据港口门座起重机的结构特点 ,定量分析上部回转自重振动对回转支承部件强度的影响 ,并基于实测数据对回转支承滚动体的接触强度进行校核 ,证明其合理性     

固定吊回转支承关键技术研究

介绍了固定吊回转支承的关键技术,通过ANSYS对650 t-33 m固定吊进行整机建模,分析回转支承处力学,得出需要添加烟胶的结论。对烟胶在3种不同刚度时对滚轮受力及变形量的分析,结果表明,使用烟胶垫时滚轮受力更趋于均匀,但过小的烟胶垫刚度将增加回转机构运行阻力,降低烟胶的使用寿命。     

门座起重机回转支承高强度螺栓连接研究

分析了门座起重机回转支承连接螺栓的受力，总结了使用中造成螺栓破坏的原因，提出了螺栓的设计方法和加工工艺。     

M16-33型门机回转支承故障诊断工作实践

回转支承装置(以下简称大轴承)是大型门座起重机的重要部件,也是主要易损部件之一 ,其工作状态良好与否将直接影响整台机器以致整条作业线的正常工作,并直接关系到操作人员和设备的安全.另外,由于大轴承维修时拆装十分困难,且修理周期长,费用昂贵,所以对大轴承的运行技术状况进行定期状态监测和早期预报,避免突发性故障的发生,做到有针对性地进行维修,可获取很大的经济效益和社会效益.     

方位和多普勒频移联合的目标要素估计

提出一种利用目标方位信息和多普勒频移信息联合估计匀速直线运动目标要素的方法。该方法适用于观测站不机动情形下目标运动分析问题。将2种目标信息分别伪线性化,建立对应的伪线性模型,利用最小二乘方法构建2个伪线性滤波器,后融合的方法得到了目标要素估计的算法。与现有的基于方位和多普勒频移进行目标要素估计的方法相比,该方法有以下不同特点：1）2个线性估计器均是二维系统,可观测性增强;2）在多普勒频移估计器中,不需要估计线谱的原信号频率。数值仿真给出了不同观测误差下的算法性能,试验验证了方法的实际有效性。     

预应力混凝土曲线梁桥支承设计初探

以实际工程为背景,介绍了曲线混凝土桥的受力特点,采用三维空间程序对小半径预应力混凝土曲线梁桥的空间效应进行分析,考虑了不同支承形式对主梁转矩、墩柱内力和支座反力的影响,指出了曲线梁桥根据平面杆系计算不能完全反映各支座的受力情况,还需进行空间计算来确定各支座反力,提出了采取支座预设偏心的措施来改善曲梁扭转效应的方法,探讨了曲线梁桥腹板开裂病害产生的原因。     

Modelling with joint choice of ports and countries of origin and destination: application to Colombian ports

Literature has focused on studying port choice independently or as an element of a supply chain without considering the joint selection with the country of origin/destination of the imports/exports. However, the characteristics and location of a port may make it more attractive to mobilise more freight from/to some particular countries rather than others, making the port choice decision dependent on the country of origin/destination of the cargo. This article proposes advanced econometric models to evaluate simultaneously port choice and the country of origin/destination choice for Colombian imports and exports. Findings suggest that for imports and exports domestic freight rate is the most important variable for the joint choice process. Also, for exports, maritime transit time is more relevant than for imports, while for the frequency of shipping lines the opposite is true. The existence of a trade agreement and the gross domestic product per capita also have a significant influence on the election of a country for exports/imports.     

高桩码头接岸结构中一种比较合理的处理形式

通过对过去高桩码头发生震害的类型及特点的分析,结合接岸结构连接处理中的常见病害及其对码头的不利影响,提出一种比较合理的高桩码头接岸结构处理连接形式。可提高高桩码头及接岸结构的抗震能力与适应能力,减少营运期的维护费用。     

Transport choice behaviour of Chinese and Australian tourists in Scotland

This study aimed to investigate and analyse the internal pre-purchase transport choice behaviour of Chinese and Australian tourists in Scotland. A literature review was carried out to explore the pre-purchase internal transport choice behaviour of tourists. A questionnaire was designed based on the findings of the literature review. A convenience sampling plan was developed to achieve a valid and statistically significant sample size for the two selected markets: Chinese and Australian tourists. Surveys were distributed directly within the Highlands and indirectly through tour operators. A number of significant differences in pre-purchase transport choice behaviour were found between independent and tour travellers and between Chinese and Australian tourists. A number of other variables including English language capabilities, country of residence, education levels and previous travel experience were also found to have significant influences on the process. A number of recommendations relating to market analysis and research, promotion and product development were made to Scottish tourism transport providers based on the findings.     

FPSO的UPS系统及其蓄电池的设计

基于FPSO项目,讨论UPS系统及其蓄电池的设计应用.针对UPS电源系统的必要性、UPS系统的结构、UPS的设计与选择、蓄电池的设计与选择及其布置原则,通过对相应规范的剖析及实船数据的验证,总结出FPSO上UPS系统的一套设计选型方法.对新建和改装FPSO项目的UPS系统设计具有一定的指导作用.     

考虑剪力滞效应的合理成桥状态的荷载检验

以某顶推施工独塔钢箱梁斜拉桥为背景,通过不同方法对比确定合理成桥状态。在此基础上,应用ANSYS软件,考虑扁平钢箱梁的剪力滞效应,对斜拉桥的成桥状态进行荷载检验,确认桥梁营运期的安全可靠。     

Multimodal route choice in maritime transportation: the case of Korean auto-parts exporters

Global offshoring has increased the need for transport of half-finished goods and components, along with finished goods. The auto-parts industry in Korea has also entered the global market as Korean car manufacturers have started to build overseas factories. Maintaining cost competitiveness by minimising total logistics costs will thus be a critical strategy for the industry. This research compares the total annual costs of four feasible transport routes from Korea to the US using the inventory-theoretic model, which encompasses direct transport costs, in-transit carrying costs, and warehouse inventory costs. We apply this model to real transport data collected from a Korean auto-parts company. A static analysis shows that inventory costs can play a decisive role in altering the cost competitiveness of different routes. In addition, sensitivity and scenario analyses with changes in variables and the market situations reveal that the cost structure of each route plays an important role in determining their relative cost competitiveness in varying market conditions.     

螺旋桨橡胶轴承压力分布分析与结构优化

由于船舶螺旋桨轴承承受的载荷呈边缘效应,尾轴与轴瓦接触压力分布不均匀。应用有限元方法建立桨-轴-轴承接触模型,分析在轴系载荷作用下橡胶轴承压力分布与变形特点。并将计算结果与实测结果进行比较,验证计算方法与模型的正确性。在此基础上提出了橡胶轴承结构优化方法,计算分析表明优化后轴承压力分布得到了明显改善,可有效降低轴承的局部严重磨损、提高轴承工作寿命。     

钻孔灌注桩竖向承载力影响因素

结合境外某跨海大桥的钻孔灌注桩试桩的静载试验成果,分析可能造成试桩竖向承载力不满足要求的影响因素。分析结果表明：土的应力释放、桩侧光滑度（尤其是桩侧泥皮）和桩端页岩强风化层饱水软化等因素是造成试桩承载力不足的主要原因。