改进弧长法求解屈曲问题

为了解决结构非线性有限元分析求解过程中结构失稳或材料出现软化时传统Newton-Raphson法无法通过极值点的问题,在传统弧长法的基础上,提出了求解过极值点问题的改进弧长法.该方法将非线性方程求解过程中出现的不平衡力向量分解为两个相互正交的向量,并建立其弧长的约束方程,求解得到非线性计算中的荷载因子.在求解过程中,给出了改进的确定弧长方法,通过弧长调整避免了求解荷载系数中出现复根的问题.通过两个拱型结构的屈曲分析算例,分别考虑几何非线性和几何材料双重非线性效应,对两个拱形结构进行了非线性屈曲分析,结果表明:结构在出现屈曲时发生急跳现象,验证了改进的弧长法在结构出现材料软化和失稳时能通过极值点.     

顺层岩质斜坡溃曲破坏机理的力学分析

分析顺层岩质斜坡的溃曲破坏模式,建立力学模型,运用梁板理论分析斜坡滑移弯曲变形破坏的机理。计算挠曲曲线的理论解,得出岩质斜坡发生溃曲破坏的临界坡长。以某桥基斜坡为工程实例,计算斜坡在天然、暴雨、暴雨+地震3种工况下的临界坡长,发现雨水和地震对斜坡临界长度有较大的影响。研究对深入理解该类斜坡的变形破坏具有参考价值。     

桩柱式基础的屈曲机理及稳定分析

论述了桩柱式基础的屈曲稳定的影响因素,基于能量法分析河床下切对桩基稳定性的影响,建立了将桩和柱视为一个整体的分析计算模型。以广东茂名下郭大桥工程为实例,分析河床下切对桩柱式基础的稳定性。计算表明:增加对桩柱的约束长度比提高地基土的性能对提高稳定性效果会更好;对于河床下切严重的桩柱式基础,提高桩侧土的性能对改善桩柱结构的稳定性能效果不是很明显。     

基于有限元法的海上风电吊装运输船起重机设计与分析

设计了最大起吊重量为460t、最大起吊高度为100m的海上风电吊装运输专用船起重机,综合运用结构单元、实体单元、连接单元和约束方程,建立了包括人字架、吊臂、回转转台部件的柔体有限元模型,并进行了典型工况下起重机力学性能有限元分析,找出设计缺陷并进行改进设计,最后对改进的起重机进行强度、刚度和屈曲分析.     

新建半潜运输船在张力腿平台运输方面的应用研究(英文)

Transportation of tension leg platform(TLP) structures for a long distance has always been associated with the use of a heavy semi-transport vessel.The requirements of this type of vessel are always special,and their availability is limited.To prepare for the future development of South China Sea deepwater projects,the China Offshore Oil Engineering Corporation has recently built a heavy lift transport vessel-Hai Yang Shi You 278.This semi-submersible vessel has a displacement capacity of 50k DWT,and a breath of 42 meters.Understanding the vessel’s applicability and preparing it for use in future deepwater projects are becoming imminent needs.This paper reviews the current critical issues associated with TLP transportation and performs detailed analysis of the designed TLP during load-out and transportation.The newly built COOEC transportation vessel HYSY 278 was applied to dry transport of the TLP structure from the COOEC fabrication yard in Qingdao to an oil field in South China Sea.The entire process included the load-out of the TLP structure from the landsite of the fabrication yard,the offloading and float-on of the platform from the vessel,the dry transport of the TLP over a long distance,and the final offloading of the platform.Both hydrodynamic and structure analysis were performed to evaluate the behavior of the transport vessel and TLP structure.Special attention was paid to critical areas associated with the use of this new vessel,along with any potential limitations.The results demonstrate that HYSY 278 can effectively be used for transporting the structure with proper arrangement and well-prepared operation.The procedure and details were presented on the basis of the study results.Special attention was also given to discussion on future use based on the results from the analysis.     

不同状腿结构的自升式平台对比分析(英文)

The jack-up unit is one of the best drilling platforms in offshore oil fields with water depth shallower than 150 meters.As the most pivotal component of the jack-up unit,the leg system can directly affect the global performance of a jack-up unit.Investigation shows that there are three kinds of leg structure forms in the world now:the reverse K,X,and mixing types.In order to clarify the advantage and defects of each one,as well as their effect on the global performance of the jack-up unit,this paper commenced to study performance targets of a deepwater jack-up unit with different leg systems(X type,reverse K type,and mixing type).In this paper a typical leg scantling dimension and identical external loads were selected,detailed finite element snalysis(FEA) models were built to simulate the jack-up unit’s structural behavior,and the multi-point constraint(MPC) element together with the spring element was used to deal with the boundary condition.Finally,the above problems were solved by comparative analysis of their main performance targets(including ultimate static strength,dynamic response,and weight).     

国外海底管道屈曲传播及止屈试验技术综述

海底管道屈曲传播机理极其复杂,涉及到弹塑性稳定后屈曲问题,须通过大量的试验进行研究.文章概述了国内外海底管道屈曲传播理论研究发展历程,着重介绍了国外在海底管道屈曲传播与止屈试验技术方面的研究,总结和评述了国外相关试验装置的特点,探讨屈曲传播压力、传播速度、止屈效率等关键因素的试验测定方法,并指明了管道屈曲传播与止屈试验技术的发展方向,为海底管道屈曲传播及止屈试验设计提供指导.     

开孔简支板格的剪切屈曲分析

目前CSR规范尚未对开孔较大的简支板格的剪切屈曲进行规定。针对这一点,采用结构非线性有限元数值分析方法,进行了一系列开孔简支板格的弹性剪切屈曲和塑性剪切屈曲的剪切极限承栽力计算分析,以尝试得出上述的屈曲能力,为规范的修订奠定基础。     

LD10-1油田井口平台加挂井槽技术研究

LD10-1油田井口平台加挂井槽项目中,对三种加挂井槽的方法(内挂井槽、外挂井槽和新增桩腿加挂井槽)进行详细分析论证,最终确定合理的加挂井槽方案。在加挂井槽的方案论证和实施工程中,对三种加挂井槽方式需要注意的共性问题和各自特点进行分析总结,为类似的工程项目提供借鉴。     

大跨度钢管混凝土拱桥施工阶段稳定性分析

以新龙门大桥为工程依托,考虑钢管和混凝土的三向受力本构关系,利用ANSYS建立了空间有限元模型,从特征值屈曲、几何非线性失稳、几何材料双重非线性失稳3个方面分析了该桥整个施工阶段的稳定问题。结果表明:钢管混凝土拱桥在整个施工过程中受稳定性影响较大,稳定系数有不断下降的趋势,考虑双重非线性的稳定系数与特征值屈曲分析相比差别较大,最大可达30%。