A new look at the external pressure capacity of sandwich pipes

Sandwich Pipes (SPs) have been developed to overcome the required flow assurance and pressure capacity issues in deep and ultra-deep waters. This research aims at studying the influence of certain structural parameters on the pressure capacity (also referred to as the plastic buckling pressure) of Sandwich pipelines. The use of high grade steel pipes, as the internal or external pipes, has also been considered as one of the design parameters in this study. Moreover, a comprehensive parametric study, considering a practical range of the parameters that influence the response of SPs (and considering 3840 SP configurations) was conducted. The results from this large array of pipes were used to formulate a practical equation, capable of estimating the plastic buckling pressure of SPs. The accuracy of the proposed equation was evaluated by comparing the results with the experimental and numerical results available in the literature. The comparative results demonstrated that the proposed equation could predict the buckling capacity of such pipes with a reasonable accuracy. Furthermore, the proposed equation was used, along with a general optimization procedure, to establish the most optimum and cost-effective combination of structural parameters for SPs suitable for use in various water depths.     

框架式结构汽车门锁系统布置匹配方法分析研究

以某款轿车的汽车门锁系统布置匹配为例,论述了汽车门锁在车身中的位置、汽车门锁与铰链轴线的位置关系,以及汽车门锁与外把手的位置关系。并总结出一种新的汽车门锁系统布置匹配方法。通过CAE分析及DMU运动分析验证了该布置方法的有效性。对样车进行耐久性试验结果可知,采用该方法布置匹配的汽车门锁系统全部零件功能正常,仅锁扣啮合处的电镀层出现轻微磨损,但符合设计要求。     

车门限位器布置设计

车门限位器作为车门系统的一个关键部件,对车门开关舒适性和驾乘人员出入车辆方便性起到重要作用。本文主要结合自身设计工作经验,阐述了常用限位器的基本布置和设计原理及方法,充分利用CATIA及EXCEL等工具建立了设计计算标准模型,希望能够使大家在同类车门限位器设计方面的理解和掌握有所助益。     

积木式工艺技术在电动汽车上的应用探讨

本文通过对＂积木式工艺技术＂的研究和应用探讨,结合电动汽车生产过程中的各技术要素,将电动汽车非最优的零部件组合,经组装—分解—再组装和优化匹配,解决电动汽车生产过程中不确定性需求与确定性生产能力之间、个性化需求与标准化生产之间的矛盾。     

调整生产布局优化组织模式积极稳妥推进电务修程改革

针对当前电务部门维修存在小站人少,单兵作战,道岔多机牵引无法正常维修,设备检修作业漏项,＂天窗＂利用不足等问题,介绍郑州电务段按照规划、试点、推进的方法和步骤,推行＂群体化＂作业模式,成立集中修工区,并以推行集中修工区为抓手,全力提高生产效率和安全管理水平。     

金华东区段站改扩建方案研究

通过对金华铁路地区及金华东区段站的现状及存在问题的分析,结合研究年度运量预测、车流组织,提出运输组织方案,确定车站工作量。在上述基础上,针对存在问题,依据"先整体后局部,定性分析结合定量计算"的原则,对改建站型方案、各场规模进行量化分析,形成改扩建框架,再细化研究各场平面布置方案。对区段站改扩建设计流程进行总结,试图找出流程化、标准化设计规律。     

城市轨道交通卸车场规模与布局研究

目前,城市轨道交通卸车场规模和布局的确定主要依靠工程经验,缺乏相应的理论研究。为了对卸车场规模和布局的确定建立相应的理论依据,采用系统分析的方法,结合工程实践,分析影响卸车场规模与布局的因素,建立卸车场规模与布局理论模型,确定各个影响因素的权重,建立城市轨道交通卸车场规模与布局评价体系,并以北京城市轨道交通14号线张仪村卸车场为实例对模型进行验证。     

铁路商品汽车物流基地功能布局方法

铁路商品汽车物流基地具有铁路与公路运输商品汽车到达、发运、装卸、商品汽车及其零配件集结、仓储、检修和清洗等功能,合理的铁路物流基地商品汽车功能区布局方法至关重要。通过分析目前铁路商品汽车运输现状及物流基地设计情况,结合规划及设计规范,提出布局合理、流程顺畅、功能完善的铁路物流基地商品汽车功能布局图,以及功能布局研究内容,并以高碑店铁路物流基地商品汽车功能区布局为例,验证所提功能布局图及布局方法的可行性。     

地铁车辆段检修库移动式架车机的工艺分析

地铁车辆段检修库中移动式架车机是车体与转向架分解组装以及车底电器、制动等模块拆装的必备设备,移动式架车机以其适用车型广、组合灵活、成本低的特点,得到广泛应用,而移动式架车机要想实现上述功能,需要分析研究与之配套设施的工艺特点。提出移动式架车机在检修库中采用有检查坑和无检查坑的布置方案,通过分析总结后,认为临修库中设置移动式架车机时,采用无检查沟的形式,在架修库设置移动式架车机时,采用有检查坑的形式。     

Synthesis of experimental designs of maneuvering captive-model tests with a large number of factors

An approach to synthesizing D-optimized experimental designs for an arbitrary number of factors was developed and tested on a third-order polynomial regression model with 5–8 factors. Three options were envisaged for the internal optimization procedure: an exhaustive search, a quasirandom search with the help of the Sobol sequences, and a genetic algorithm. The calculations performed have shown the pronounced superiority of the variant involving a genetic algorithm. Captive-model tests with a catamaran model with varying Froude number, drift angle, rate of yaw, sinkage, trim, and heel are presented as an example of the practical synthesis of the experimental design. The linear regression model constructed is a third-order 5-factor polynomial with respect to all factors except the Froude number. The influence of the latter is accounted for by representing the polynomials regression coefficients as functions of the Froude number represented as a truncated Fourier series with a linear term added.