Lateral buckling of subsea pipelines triggered by combined sleeper and distributed buoyancy section

In order to release the axial compressive force resulting from high-temperature conditions, sleepers or distributed buoyancy sections are usually installed along the route of the subsea pipeline as the buckle initiation facilities to trigger lateral buckles. DNV-RP-F110 suggests that the individual buckle initiators can be combined to further increase the reliability of buckle formation. In this study, an improved buckle initiation technique, called the combined sleeper and distributed buoyancy section, is investigated. A generalised mathematical model is proposed to simulate lateral buckling triggered by the combined sleeper and distributed buoyancy section, and it can also be applied to simulate lateral buckling triggered by an individual technique, such as triggered only by sleeper or only by distributed buoyancy section. The mathematical model is verified by comparing with the solutions in the literature. The parametric analysis shows that the buckle formation reliability can be improved when the combined sleeper and distributed buoyancy section is employed. Moreover, both the axial force and the maximum stress along the buckled pipeline in the post-buckling stage are at a lower level, so the pipeline will be safer when the combined sleeper and distributed buoyancy section is utilised as the triggers.     

超高速磁浮车-轨道梁竖向耦合振动分析

针对超高速磁浮车-轨道梁竖向耦合振动的问题,提出一种基于轨道梁有限单元模型和磁浮力比例-积分-微分(PID)控制器模型的分析方法。为提高计算效率,整体耦合系统以磁浮力为界,分为车辆和轨道梁2个子系统,车-梁之间的振动耦合则通过PID控制器计算的磁浮力来完成。组成耦合系统的子系统分别采用振型分解法和四阶龙格库塔法计算其振动响应。为验证方法的有效性以及了解超高速磁浮车桥耦合振动特性,使用Mathematica编程进行超高速磁悬浮车-轨道梁的耦合振动分析,得到运行速度为600km/h的车辆和轨道梁的动力响应。研究成果可为超高速磁浮轨道结构设计和关键技术研究提供参考。     

深水塔式立管顶部浮力筒设计分析方法

研究深水塔式立管顶部浮力筒初步设计分析的基本流程与方法,涉及的技术难点包括顶部浮力筒设计中阻力最小化与浮力最大化的优化、浮力筒舱室的数量与尺寸的确定、单/多个浮力筒舱室破坏时浮力的裕量等。总结顶部浮力筒设计参数对设计性能影响的基本规律,并给出顶部浮力筒分析校核的主要工况载荷。以西非海域深水油气田为例,对深水塔式立管顶部浮力筒进行设计分析。范例表明提出的设计分析方法行之有效。     

大深度载人潜水器浮力块的结构设计

依据大深度载人潜水器浮力块的使用条件及主要技术性能指标,提出了浮力块的质量和质心坐标的计算方法、布置和分块原则、强度校核标准,并通过对浮力块密度测试和水压试验,测得了浮力块的主要物理性能参数。上述研究结果为浮力块的结构设计、编制我国大深度载人潜水器入级和建造规范中浮力块的结构设计、以及研制同类大深度水下载人/无人潜水器(HOV,ROV,AUV)提供了依据。     

潜艇储备浮力论证研究方法分析

运用模糊综合评判方法对潜艇储备浮力的选取进行论证评估,讨论了在“小分舱大储备浮力”以及“大分舱小储备浮力”两种不同观点下潜艇储备浮力论证的评估模型.通过对航速、水面抗沉性、结构和系统3个不同因素对潜艇储备浮力影响的模糊评估分析,对各种储备浮力值的优劣进行评判,确定储备浮力的最佳值,为潜艇储备浮力设计的选优提供依据.     

2×110kW推轮的设计及应用

为适应长江、汉江干支运输,本文设计了2×110KW推（拖）轮,介绍了该轮的主要数据及技术性能,并从船体艉部线型、浮心位置、螺旋桨及振动和噪声等方面作了改进,经使用其技术性能,从纵方式、建造质量等均达到了同类船型的先进水平。     

About process times in some deepwater formation events in the Mediterranean Sea

Experimental data gathered on some Mediterranean deepwater formation sites have been analysed in order to check the Chapman (Ch), Visbeck and Maxworthy scale laws, their final mixing water depth and process times estimates. All the analysed sites have a high probability to be “internally constrained” so that the baroclinic Rossby radius is the dominant horizontal length scale and the final chimney depth is independent of the rate of rotation as indicated by Visbeck and Maxworthy criteria; the Eady instability times are generally very fast (3/f) but the least final mixing process times are too long compared with the meteorological forcing ones. It is attempted here to identify some new criteria to give some insight on the processes time scale, which is still an open problem. Conclusions about the Rhodes gyre appear questionable, because the experimental data appear inconsistent with any theoretical criterion.     

利用浮托力弥补打桩船吊装能力的不足

针对混凝土大直径管桩沉桩施工时打桩船吊装能力存在不足的问题进行了分析,提出了利用管桩空腔排水产生的浮托力来弥补的措施。沉桩结果表明,这种方法是切实可行的,对类似工程的沉桩施工具有参考价值。     

船闸人字闸门浮箱的设置方法

大型船闸人字闸门通常设置浮箱以改善顶底枢运转件的受力状态,降低门头下垂量。在同等浮力下,先对比矩形、U型、⊥型、L型、J型、T型、Π型等7种不同形式的浮箱,分析顶底枢支反力、门头下垂量、固有频率、通气路径等特性,给出相对合理的浮箱结构形式;在此基础上,再对比1层、1层半、2层、3层、4层等5种不同浮力大小的浮箱,分析并给出相对合理的浮箱浮力控制范围。     

深海载人潜水器外部结构设计研究

全面总结了某深海载人潜水器外部结构中的载体框架、浮力材料、轻外壳、稳定翼的设计工作,对各种外部结构在载人潜水器中发挥的作用、材料的选取、设计思想、设计载荷和安全系数的确定、强度分析与校核等方面进行了详细的论述,以便为今后建造类似的载人潜水器提供参考.