基于多重静态子结构的浮桥接头受力分析

本文以基于某型浮桥基本构型,对主尺度作适当变化的概念浮桥为研究对象,基于有限元静力缩聚理论,采用多重子结构分析方法分析模块化拼组的浮桥结构,利用弹性地基板单元模拟浮力,根据模块间拼组接头的连接特点,将接头连接效应考虑成节点自由度耦合,采用超单元拼组方法建立了河中舟和临界长浮桥有限元模型,对浮桥进行了最不利加载,经过求解,提取、分析了浮桥结构纵向拼组接头以及最不利河中舟横向拼组接头的接头力,相关分析方法可以为浮桥接头设计优化提供技术支撑。     

游艇码头拉簧锚碇式浮桥结构应力与运动响应分析

波浪条件是游艇码头浮桥结构设计的控制性因素.针对拉簧锚碇式混凝土浮桥结构在波浪作用下运动和受力情况复杂的问题,依托实际工程,归纳游艇码头浮箱和锚碇结构选型的一般思路和原则,找出拉簧锚碇式混凝土浮桥的适用情况和结构设计要点,并通过有限元分析拉簧锚碇式混凝土浮桥在波浪作用下的运动响应及结构应力特点.结果表明,波浪超过0.5...     

游艇浮码头定位桩内力计算方法探讨

以海河内某游艇码头为例,通过Autodesk Robot建立浮桥定位桩计算空间有限元模型,对游艇码头定位桩内力进行数值计算分析,为今后游艇浮码头定位桩设计提供参考。     

FPSB与连接浮桥耦合运动响应分析

作为一种用于岛礁开发的新型浮式结构物,FPSB(Floating Production Storage Bridge)通过浮动式栈桥与近海岛礁连接。现有规范及理论缺乏连接浮桥对船体运动响应影响的计算方法,因而本文基于三维源汇分布法,建立船体与连接浮桥准静态的六自由度耦合运动方程,编制程序计算浮桥影响下船体的运动及载荷,并分析满载工况下考虑连接浮桥前后的船体运动响应和载荷响应。数值结果表明,连接浮桥对船体的垂荡和纵摇运动影响较大,计入浮桥影响后船体的垂向弯矩和垂向剪力的幅值总体上呈变大的趋势。本文研究成果对船体和连接浮桥耦合运动计算具有参考意义和实用价值。     

波流联合作用下通载浮桥动力特性研究

为了研究波流环境中浮桥通载时的动力特性,探讨通载速度及波流联合作用对浮桥动力响应的影响,本文采用势流理论对浮桥所处流场的速度势进行分析,采用莫力森公式计算浮桥受到的水阻力,同时考虑多轴移动荷载的影响,建立系泊浮桥的时域运动方程;并对不同工况下浮桥的运动响应及系泊力进行了计算,在计算中考虑了瞬时湿表面变化对浮桥浮力及水阻力的非线性影响,通过计算得到了不同行驶速度、不同波况下浮桥各桥节的运动响应及系泊力时程曲线.结果表明:车辆行驶速度对浮桥桥节垂荡、纵摇响应及系泊力均具有明显影响,桥节垂荡、纵摇及上游系泊缆张力峰值随行驶速度增大而增大;通载浮桥中部桥节的系泊缆张力最大值小于两侧桥节系泊力最大值;波浪作用下桥节的运动响应及系泊力与车辆荷载引起的运动响应及系泊力具有一定程度的叠加效应,特别是垂荡响应的叠加效应更为明显;当波高较大时系泊力将由波浪作用控制.     

波浪作用下带式舟桥的水弹性响应研究

对于设计和使用在波浪和流作用下作业的浮桥,充分了解其水弹性性能尤为重要.就在国防和桥梁工程中极为重要的带式舟桥而言,预报其在波浪中的水弹性响应在实际工程中就显得十分必要.该文主要研究带式舟桥在波浪作用下的水弹性性能.首先,简要地介绍了预报浮桥动力响应的不同方法及它们与试验比较的结果;其次,在三维水弹性理论的基础上采用模态叠加法对带式舟桥的有限元模型进行了水弹性分析,同时与十分之一模型试验结果做了比较(该试验由上海交通大学海洋工程国家重点实验室承担).研究表明,文中的方法计算分析波浪中浮桥的水弹性响应是可行的.     

围裙连接件的改进设计及验证

围裙寿命到期更换时,发现艏部围裙内安装边、艉转角围裙外安装边处连接件出现围裙连接件断裂和连接失效的情况,本文对出现问题处围裙连接件进行原因分析,采用ANSYS有限元软件对失效部件进行仿真模拟,通过多方案改进、拉力试验及对比分析来验证改进设计的合理性和可靠性,为后续产品的更换和使用提供依据。     

基于有限元和实验模态的螺栓连接板分析

以MSC.PATRAN软件为基础建立有限元螺栓连接模型,并通过试验模态验证连接方式的正确性。结果表明,该有限元螺栓连接模型具有较高精度的动态响应特性;结合实验模态建立的有限元模型可以准确地计算出结构频率和振型,为后续的动态设计提供理论依据。     

关于浮桥式游艇码头系泊允许波高的探讨

本文结合我国游艇码头设计规范,对比澳大利亚、英国、美国、日本等国家的规范、标准,综述分析各标准中关于游艇码头系泊条件的规定,探讨浮桥式游艇码头的系泊允许波高,成果可为游艇码头设计提供参考.我国现行规范与澳大利亚标准(AS 3962:2020)的最大允许波高基本相符,较其他国外标准略偏宽松.建议在游艇码头设计时,浮桥式游...     

花瓣形沉箱在波压力及贮仓压力作用下的数值分析

沉箱式码头在现代港口工程中应用越来越广泛,沉箱形状也越来越复杂。依靠常规的设计方法往往难以确定复杂形状的沉箱结构内力分布。采用大型有限元分析软件ANSYS对摩洛哥Tangier港码头工程的花瓣形沉箱进行有限元分析,得到沉箱在波压力和贮仓压力作用下内力分布规律,可为沉箱设计提供依据。     

Hydroelastic analysis of a nonlinearly connected floating bridge subjected to moving loads

In this paper, the motion equations for the nonlinearly connected floating bridge, considering the nonlinear properties of connectors and vehicles’ inertia effects, are proposed. The super-element method is used to condense the whole calculation scale, and the direct integration and Newton–Raphson iteration method are applied to solve the reduced equations. Based on the modal and static analyses, the dynamic displacement and connection forces characteristics of a floating bridge with nonlinear connectors subjected to moving loads are investigated. It is found that nonlinearity and initial gap of the connectors are important for the hydroelastic response of a nonlinearly connected floating bridge.     

Experimental and numerical study on dynamic responses of floating bridge under the shielding effect of a floating platform

A floating bridge and a floating platform can serve as a transport channel between land and sea. They will interact with each other in the wave environment. In this paper, the dynamic response characteristics of a floating bridge under irregular waves and regular waves are studied by means of model tests and numerical calculations. The results of model test and numerical calculation based on potential flow theory are basically consistent and can be mutually verified. By comparing and analyzing the dynamic response results of the floating bridge under the condition of “with floating platform” and “without floating platform”, some conclusions are drawn. The floating platform will have a shielding effect on waves coming from the sea. Due to the shielding effect of the floating platform, the motions in heave, surge and pitch of the floating bridge are evidently diminished. Among them, the motion response of the pontoon near the floating platform decreases most obviously. The floating platform provides a relatively stable marine environment for the floating bridge, thereby improving the survival state of the floating bridge.     

深海系泊浮体物面非线性时域耦合动力分析

文章基于三维时域势流理论和弹性细长杆理论,研究并提出了深海系泊浮体物面非线性时域耦合动力分析方法。该方法采用时域物面非线性理论方法在瞬态位置直接时域模拟系泊浮体所需水动力,结合有限元方法计算系泊缆索的动力响应,利用异步耦合方法实现浮体和系泊缆索的时域耦合动力求解。既满足系泊浮体时域水动力耦合,又满足系泊浮体和系泊缆索动力耦合。通过对二阶非线性不规则波作用下深海系泊半潜式平台的时域耦合响应特性进行研究,将不同海况下物面非线性时域耦合静力响应和动力响应与间接时域耦合动力响应的三种方法计算结果进行比较。研究结果表明,系泊缆索动力响应明显,平台瞬态空间位置对垂荡低频运动影响较大,有必要在平台瞬时湿表面采用动力响应方法进行深海系泊浮体时域耦合响应分析。     

Effects of structural flexibility on the dynamic responses of low-height lifting mechanism for offshore wind turbine installation

Installation complexities are one of the major challenges in the floating offshore wind turbine (OWT) industry. The modern concept introduced by the SFI-MOVE project is an effort to overcome the complexities by utilizing a low-height lifting mechanism. It is common to idealize a crane in the lifting mechanism as a rigid body since the structural deflections are smaller than the responses introduced by the other system components. However, structural flexibility can play an essential role in demanding offshore operations with smaller acceptable tolerances. In this study, lifting cranes are modeled using the finite element method and simplified by implementing equivalent 3D beam elements. Dynamic analysis is performed for various environmental conditions, and the responses of the crane structure and the OWT are calculated for each load case. This research reveals that crane structure flexibility influences the relative motion between a floating spar buoy and an OWT during mating operations. Crane structural flexibility contributes significantly to the OWT rotations. In addition, the response deviation between using rigid and flexible cranes increases as the excitation force increases. Therefore, it is recommended to consider the crane structural flexibility in the calculation when strict installation tolerances are needed.     

A study on slamming pressure on a flat stiffened plate considering fluid–structure interaction

Normally, the design slamming pressure on the bottomof a semi-submersible-type floating rig is determined in a simple way using the relative speed obtained from an air-gap analysis. However, few studies have taken a thorough, robust, and deep-background approach to the estimation of design pressure. To investigate the slamming pressure on the bottom of a semi-submersible rig, a simplified deformable stiffened plate of a zero-degree deadrise angle is simulated using the nonlinear FEM software LS-DYNA, which can take the influence of fluid–structure interaction (FSI) into account. Various parametric studies are carried out to examine the effects of structural flexibility, coupling stiffness, mesh size, velocity, stiffener size, and air cushion. The pressure response on the plate by the coupling of fluid and structure is studied and the FSI effect of each parameter is discussed. Then, equivalent transient and static loads that result in the same maximum or permanent deformation as FSI are evaluated for design purposes through a series of parametric studies.     

超大型浮体模块柔性连接功能仿真模型试验研究

精确评估模块柔性连接性能对连接器和超大型浮体的结构安全性具有重要意义,而模型试验是获取超大型浮体模块柔性连接性能的必要手段。文章以横向浮筒式的浅吃水超大型浮体为研究对象,根据连接器动响应计算结果,设计了柔性连接器模型;通过不同幅值和载荷组合的连接器静态拉伸和压缩试验,研究了超大型浮体连接器的刚度特性,探讨了组合载荷对连接器刚度的影响;通过不同幅值和周期的连接器纵向动态载荷试验,研究了超大型浮体连接器在动态载荷作用下的结构响应,验证了超大型浮体连接器结构的安全性和适用性。试验结果表明在静态和动态载荷作用下文中设计的柔性连接器连接可靠、结构安全,连接器载荷、位移和应力测量结果可为验证连接器结构设计和计算方法提供依据。     

Experimental investigation on hydrodynamics of floating cylinder in oscillatory and steady flows by forced oscillation test

In this paper the hydrodynamic characteristics of a floating cylinder are investigated via forced oscillation experiments in towing tank. The effects of Keulegan–Carpenter number, Reynolds number, reduced velocity and overtopping on hydrodynamics of the floating cylinder in oscillatory and steady flow are studied. The results show a considerably difference of the hydrodynamic characters between the floating and the fully immerged cylinders due to the influences of free surface. The growth of the reduced velocity, a proven notable effect on hydrodynamics, will lead to the increase of added mass coefficient and the decrease of drag coefficient. Meanwhile the overtopping, a particular phenomenon for the floating cylinder, render the added mass coefficients reach up to 3.6 while for the drag coefficient small influences were made.     

浮码头与旁靠船舶的运动响应特性研究

本文基于三维势流理论，采用数值分析方法研究了浮码头与散货船旁靠系泊的运动特性。考虑缆绳和护舷的非线性特性，探求了波浪周期对浮体运动、系缆力的影响规律。研究结果表明：考虑间隙内水体运动影响，旁靠散货船在横浪条件下的纵摇和纵荡运动有所增大。浮码头在计算工况下，缆绳受力较大，在某些工况条件下超出了国际系缆力标准的要求，旁靠散货船的缆绳在计算工况下均未超标，满足要求。研究结果为浮码头系泊系统的设计及工程运营提供理论参考。     

预应力混凝土连续梁桥合龙顺序对结构内力的影响分析

分析了三跨一联连续梁桥悬臂施工不同合龙顺序可能导致主梁与支座间存在＂间隙＂的缺陷,用MIDAS/Civil程序分别计算了在不同合龙工序状态下,结构内力和变形的变化值。结合实例,模拟计算了当主梁与支座间分别存在1～5 mm间隙时,对主梁内力的影响。理论计算表明,当主梁与支座间存在较小间隙时（3 mm以下）,采用适当的合龙工序,在具有季节性施工的地区,更具有工程实用价值。