兴安岭山地低信噪比地震资料处理技术分析

大、小兴安岭山地地表大多被火山岩、火山岩风化形成的残余物和腐植土所覆盖，地震资料中普遍存在较强的折射波和多次折射波，资料的信噪比很低；此外，该区低、降速层厚度和速度横向变化剧烈，静校正问题突出，为此，开展了有针对性的处理方法研究。针对山地地表起伏大的特点，采用了浮动基准面方法；针对低、降速层厚度和速度横向变化剧烈的特点，采用了折射静校正和微测井静校正相结合的方法；针对折射波强的特点，采用了t—x域叠前相干压制方法；针对叠加剖面随机噪声严重的特点，采用了f—x域随机噪声衰减方法。实际资料处理表明，采用上述处理手段，提高了资料的信噪比，增强了同相轴的连续性，突出了反射波组特征。     

有限单元法在基础设计中的应用

有限单元法随着计算机的发展而迅速发展,在土木工程中应用越来越广泛,有着其他方法无可比拟的优点,同样在基础设计中有限元法也得到了应用,以筏板基础有限元计算为例,阐述了计算软件利用有限单元法计算的步骤.     

泥沙的“旋浮”

阐述了螺旋管流中泥沙“旋浮”的机理，运动轨迹、含沙量分布、挟沙力及能耗诸方面的理论分析与试验结果，并讨论了它与悬浮的关系，为工程应用提供可靠的依据。     

基于MSC.Patran的浮筏冲击响应分析计算系统的设计实现

利用MSC.Patran和MSC.Nastran进行浮筏系统的冲击动响应分析计算是一项烦琐而复杂的过程,定制开发浮筏冲击动响应分析计算系统具有重要的应用价值.描述了系统的设计框架及功能模块,介绍了系统的具体实现及工作流程.为了充分利用已有的数据资源,系统中实现了MSC.Patran与已有浮筏数据库系统的交互.通过一个工程示例,说明了系统的有效性.     

新型GPS-RTK打桩船定位系统在苏通大桥建设中的应用

苏通大桥南主塔墩第一期基桩钢护筒采用大型打桩船插打施工,利用GPS-RTK卫星定位系统进行打桩船的导航定位。该文说明了GPS-RTK打桩船导航定位系统的原理及构成;简述了打桩船导航定位的作业过程;通过对已插打完成的钢护筒平面位置及垂直度统计,分析了此方法的施工质量。     

超大型浮式平台风载荷计算

针对超大型浮式平台上层建筑台风状态下风载荷,分别采用中国船级社(CCS)、挪威船级社(DNV)规范和实尺度计算流体动力学(Computational Fluid Dynamics, CFD)计算等3种方法进行计算,并对计算结果进行对比分析。CFD方法与DNV规范方法计算结果较为一致,当风向角为135°和225°时最大误差为10.19%,在其他风向角时误差小于8%。构建平台空间位置风载荷影响分析方法,可通过云图形象直观地看出不同风向角下平台横向和纵向空间位置对风载荷的贡献量及模块间遮蔽效应的影响程度。研究成果可为平台设计人员更合理地评估风载荷提供参考,为进一步优化平台上层建筑构型提供指导。     

应用DDAM进行船舶浮筏隔振装置抗冲击计算

研究舰船设备冲击设计分析方法,对美国海军动力学设计分析方法(DDAM)进行了详细介绍。分别按照美国海军NAVSEA 0908-LP-000-3010,Rev.1和GJB1060.1-91的要求对船舶浮筏隔振装置进行了冲击设计分析,计算表明修订后的DDAM计算结果更准确。计算分析方法可用于海军舰船设备的冲击设计分析,计算应按照美国海军NAVSEA 0908-LP-000-3010,Rev.1要求的模态选择标准进行。     

Design and model confirmation of the intermediate scale VolturnUS floating wind turbine subjected to its extreme design conditions offshore Maine

Floating offshore wind turbines are gaining considerable interest in the renewable energy sector. Design standards for floating offshore wind turbines such as the American Bureau of Shipping (ABS) Guide for Building and Classing Floating Offshore Wind Turbine Installations are relatively new and few if any floating wind turbines have yet experienced the prescribed design extreme environmental conditions. Only a few pilot floating turbines have been deployed in Europe and Japan. These turbines have been designed for long return period storm events and are not likely to see their extreme design conditions during early deployment periods because of the low probability of occurrence. This paper presents data collected for an intermediate scale floating semi‐submersible turbine intentionally placed offshore Maine in a carefully selected site that subjects the prototype to scale extreme conditions on a frequent basis. This prototype, called VolturnUS 1:8, was the first grid‐connected offshore wind turbine in the Americas, and is a 1:8 scale model of a 6 MW prototype. The test site produces with a high probability 1:8 scale wave environments, and a commercial turbine has been selected so that the wind environment/rotor combination produces 1:8‐scale aerodynamic loads appropriate for the site wave environment. In the winter of 2013–2014, this prototype has seen the equivalent of 50 year to 500 year return period storms exercising it to the limits prescribed by design standards, offering a unique look at the behavior of a floating turbine subjected to extreme design conditions. Performance data are provided and compared to full‐scale predicted values from numerical models. There are two objectives in presenting this data and associated analysis: (i) validate numerical aeroelastic hydrodynamic coupled models and (ii) investigate the performance of a near full‐scale floating wind turbine in a real offshore environment that closely matches the prescribed design conditions from the ABS Guide. Copyright © 2015 John Wiley & Sons, Ltd.     

Dynamics of offshore floating wind turbines—analysis of three concepts

This work presents a comprehensive dynamic–response analysis of three offshore floating wind turbine concepts. Models were composed of one 5 MW turbine supported on land and three 5 MW turbines located offshore on a tension leg platform, a spar buoy and a barge. A loads and stability analysis adhering to the procedures of international design standards was performed for each model using the fully coupled time domain aero‐hydro‐servo‐elastic simulation tool FAST with AeroDyn and HydroDyn. The concepts are compared based on the calculated ultimate loads, fatigue loads and instabilities. The loads in the barge‐supported turbine are the highest found for the three floating concepts. The differences in the loads between the tension leg platform–supported turbine and spar buoy–supported turbine are not significant, except for the loads in the tower, which are greater in the spar system. Instabilities in all systems also must be resolved. The results of this analysis will help resolve the fundamental design trade‐offs between the floating‐system concepts. Copyright © 2011 John Wiley & Sons, Ltd.     

海上浮式水平轴风力机气动特性研究

以NREL-5MW风力机为研究对象,基于叶素动量理论,考虑动态失速、风剪切及塔影效应等气动修正模型,开发Matlab非定常气动载荷计算程序,研究浮式水平轴风力机气动特性.结果表明:为保证风力机气动载荷模拟的正确性,气动修正模型必不可少;基础运动对风力机气动性能有显著影响,基础运动使风力机输出功率增大,但同时存在较大的振...