气温升高对多年冻土地区路基稳定性影响

为了分析在气温升高的状况下冻土退化对东北多年冻土地区路基稳定性的影响,假设气温年增长率为0.05℃,通过ANSYS有限元软件计算了不同地表状况和不同含冰量情况下,多年冻土最大季节融化深度变化,根据不同土质、不同含冰量的融沉系数,计算得到不同含冰量冻土的沉降量.结果表明:在气温逐年升高的状况下,含冰量大的土层沉降量大于含...     

浅谈道路交通地理信息系统研究框架

针对地理信息系统在道路交通领域的应用 ,就研究发展方向谈了自己的认识和看法     

海外铁路信号市场特征与铁路信号“走出去”策略建议

伴随我国铁路制造业"走出去"战略实施,我国承建的海外铁路项目逐年增加,但由于不同地区既有信号制式、规范以及业主既有运营维护习惯等诸多方面的差异,使我国铁路信号设备走出国门面临巨大挑战。结合部分国家的实际情况,对铁路信号海外市场的特征进行分析,并对我国铁路信号设备制造企业、海外铁路项目承包企业及整个信号行业的应对策略提出相关建议。     

基于GPS、GIS技术的桥梁结构健康监测与管理信息系统

分析了GPS、GIS技术在桥梁结构健康监测与管理系统中应用的可行性,对基于GPS技术、GIS技术、数据库技术和网络技术为一体的桥梁结构健康监测与管理信息系统进行了研究,并对其实现机制进行了较为详细的阐述。     

Three-dimensional pipeline element formulation for global buckling analysis of submarine pipelines with sleeper

Submarine pipelines can utilize sleepers to control global buckling location, which mitigates potential risks under high temperature and pressure. However, pipelines with sleepers require execution in three-dimensional space and experience lateral buckling modes. As such, this paper proposes a 3D pipeline element for lateral buckling analysis, building on previous 2D element formulations. This new element considers non-linear pipe-soil interactions, thermal expansion, axial load, initial imperfections, large deflection, and other major factors that affect lateral buckling. The derivations of the 3D pipeline element are provided in detail, and the numerical analysis procedure is elaborated. To validate the accuracy and efficiency of the proposed 3D pipeline element, several examples are presented.     

半潜式平台总体强度计算和关键结构极限强度计算方法研究

给出了基于ANSYS/AQWA软件的半潜式平台整体强度分析方法,采用逐步破坏分析法和有限元计算方法,计算半潜式海洋平台关键节点和关键构件极限强度。以一典型深水半潜式平台为对象,进行了自存工况和作业工况下8个典型危险波浪载荷条件下的平台整体强度有限元分析,选取应力最大的横撑和立柱局部结构作为计算模型,确定合理的边界条件,通过计算给出了半潜式平台关键节点和关键构件的极限承载力,为下一步平台结构的安全性评价提供可靠依据。     

Global logistics city concept: a cluster-led strategy under the belt and road initiative

This paper develops a cluster-led strategic policy framework to assess the strategic positioning of key global logistics cities in Asia, most of which are affected by the ‘Belt and Road (B&R) Initiative.’ One of the key challenges that the B&R Initiative is facing is underdeveloped logistics infrastructure in Asia, not to mention road congestion, dilapidated infrastructure, incessant supply chain disruptions, and capacity constraint, which imposes significant economic costs.

Global logistics cities are evaluated on logistics infrastructure capacity and service responsiveness. This involves selecting the key global logistics cities, identifying key indicators, standardising and indexing, mapping dimensions of global logistics cities, and developing the cluster-led strategic policy framework.

The results indicate the prevalence of a multi-tier system wherein Shanghai and Hong Kong have attained the maturity of a global logistics city, whilst Manila, Jakarta, and Bangalore are making slow but steady progress in that direction. In contrast, Dhaka, Phnom Penh, and Ho Chi Minh City are showing potential but require further enhancement through significant investment in infrastructure and service delivery improvement.

The cluster-led strategic policy framework formulates actions and strategies through which emergent logistics networks can be strategically aligned and functionally integrated with B&R-oriented global trading hubs and transport corridors..     

Experimental and theoretical studies on lateral buckling of submarine pipelines

Global buckling of a submarine pipeline during high pressure/high temperature (HP/HT) operation results in a loss of pipeline stability that is similar to a bar in compression; this phenomenon constitutes one of the key factors affecting pipeline integrity and design. To intuitively study the buckling response, a test system was designed that can account for thermal loading and pipe-soil interactions, and this system was used to perform a series of small-scale model tests on the lateral buckling of submarine pipelines with different initial imperfections. Based on the hat-shaped buckling profiles of the test pipelines, a new buckling mode called "hat-shaped buckling" was proposed. In an attempt to study the conditions under which the pipeline exhibits this hat-shaped buckling mode, the changing law of the buckling mode was investigated through finite element analyses of pipelines with different parameters, including the length of the pipeline and the amplitude and wavelength of the initial imperfection. Subsequently, an analytical solution for calculating the buckling amplitude of a pipeline with a hat-shaped buckling profile was proposed. The theoretical solution was compared to the experimental data, which verified the feasibility of the model in calculating pipeline buckling deformation. The experimental data, the buckling mode based on these data and the corresponding analytical model discussed herein may provide a reference for future experimental studies of pipeline buckling.     

Coarse mesh finite element model for cruise ship global and local vibration analysis

This paper presents a practical procedure for creating finite element (FE) model for vibration analysis of cruise ships. The most preferable FE modelling approaches are studied and discussed through case studies of common ship structures, which cover the range from low to high frequencies. The application of homogenized equivalent single layer (ESL) theory based equivalent element for stiffened panel is extended to local forced vibration analysis, where inertia induced interaction between plate and stiffener occurs. Modal method is used with an energy-based correction for accounting the plate-stiffener interaction into modal properties. Case study results reveal that mesh density of one 4-node element per web frame spacing is suitable for global FE-model when vibration analysis is limited to global hull girder modes. For such modes it is sufficient to only include the membrane stiffness of stiffened panels. For investigating the response at higher frequencies, bending properties of stiffened panel should be included and mesh density should be at least two elements per web frame spacing. Then forced vibration analysis can be performed with an excellent accuracy up to frequencies about one third of the local plate natural frequencies between the stiffeners. Beyond that, the influence of the local plate vibration becomes more significant in panel vibration, making the ESL-theory based element limited. With the applied correction method, the validity of the ESL-model can be extended to approximately two thirds of the local plate natural frequency.     

Dynamic responses analysis of a 5 MW spar-type floating wind turbine under accidental ship-impact scenario

Ship impact against offshore floating wind turbine (OFWT) has been identified as one of the major hazards with the development of OFWTs. The dynamic responses of OFWTs under ship impact should be taken into consideration during the design phase. This paper addresses a study on the dynamic responses of an OFWT in ship collision scenarios. Firstly, a mathematical model for external mechanism of ship-OFWT collision scenario is developed. Secondly, this model is combined with an in-house programme, DARwind, which can be used to predict nonlinear dynamic responses of whole OFWT system in time-domain. With the newly combined analysis tool, simulation cases for different scenarios are conducted to investigate the nonlinear dynamic responses of OFWT system, including the cases of still water condition, wave-only condition and wind-wave condition. It is shown that in still water condition, the ship impact will more obviously change the responses of motions and mooring system, compared with those in wave and wave-wind conditions. In the wave-only condition, these motions responses of platform are suppressed by wave effect, but the tower vibration and tower top deformation are sensitive to ship collision. For the wave-wind combined condition, the motions increment in surge and pitch due to ship collision becomes smaller than that of wave-only condition, but yaw motion has a considerable variation compared with those of the other two conditions. Additionally, the blade tip deformation increment due to ship collision are analyzed and it is found that the edgewise tip deformation got more obvious increment than that of flapwise. To further asses the safety of OFWT, the acceleration at nacelle are analyzed because some equipment might be sensitive to acceleration. The analysis results indicate that even though the OFWT structure doesn't get critical damage by ship impact, the equipment inside may still fail to work due to the high value of acceleration induced by ship impact. The research outcomes can benefit the safety design of OFWT in the engineering practice.