【作者】 彭涛；

【导师】 陈永亮； 许威；

【作者基本信息】 天津大学 ， 机械工程， 2018， 硕士

【摘要】 张力系索是海洋石油张力腿平台(TLP)的重要结构组成部分,系索一般是由多段长度相同的等壁厚管道通过焊接或是机械连接而成。与机械连接技术相比,管道的焊接技术受水深的影响较大,容易产生应力集中且焊接接头质量差;对于尺寸较大的管道,焊接方式具有对中困难、操作不便,效率低且能耗高,同时伴随着环境污染等缺点。而管道机械连接技术具有安装方便、易于更换且受水深影响较小等多重优点,近年来在国内外受到高度重视。本文研究的应用于TLP张力系索的液力套装式机械连接器是一种新型管道连接器,适用于深度1500米的深水区,且具有比现场焊接更高耐疲劳强度、无需旋转、比螺纹连接安装快速等优点。由于深水海洋平台管型结构安装使用工况复杂、尺寸系列范围覆盖广;对于液力套装式机械连接器,缺少可快速设计和优化的解析模型,本文从以下几个方面对其作出了研究。首先,基于连接需求分析的基础上,阐述了机械连接器的结构方案及安装过程,对机械连接器结构参数进行了规划。考虑实际作业承载需求以及连接器的安装过程,阐述了连接器整体及主要承载部分齿形的力学模型,提出了连接器正确安装所需满足的安装要求以及安装内压应满足的条件。其次,根据连接器的力学模型,提出了确定机械连接器关键结构参数的优化数学模型,优化的目的是在满足应力强度及安装要求的条件下,获取使连接器总体重量最小的结构参数。对于优化模型,采用了三种优化算法:非线性规划算法、遗传算法和非线性规划遗传算法对其进行了求解,得到了机械连接器的结构参数。对三种算法的优化过程进行对比,结果表明,非线性规划遗传算法是求解该模型的最优选择。再次,介绍了在Creo三维建模软件中,对机械连接器进行参数化建模的过程。提出了连接器需要满足正常安装和使用的条件。利用优化参数建立机械连接器三维模型,将模型导入Abaqus软件中,对连接器进行了安装条件及使用条件下的仿真,结果表明,优化后的连接器参数可以满足安装和使用要求。考虑三种不同结构形式,对连接器进行有限元仿真对比,通过对比结果得到了比较好的结构形式。考虑过渡圆弧处的安装厚度变化,对连接器进行了仿真对比,得出了受过渡圆弧厚度影响的安装规律。最后,考虑机械连接器应用于TLP系索的实际作业需求,对机械连接器进行了疲劳分析。利用Creo软件建模导入AQWA软件中,对TLP平台进行了水动力分析,得到了系索顶端与平台连接处的载荷谱,根据该载荷谱,在ABAQUS进行静力学分析,得到连接器易于疲劳的热点。针对疲劳热点,基于S-N曲线和Miner累积损伤理论对连接器疲劳累积损伤及疲劳寿命进行了计算,结果表明连接器热点处的疲劳寿命及疲劳损伤均满足要求。更多还原

【Abstract】 The tethers of TLP tendons is an important part of the general structure of offshore tension leg platform(TLP),which is generally composed of a plurality of the same length and wall thickness of pipes by welding or mechanical connection.Compared with the mechanical connection mode,the welding of pipeline is affected greatly by water depth,which is easy to produce stress concentration and poor quality of welded joint;For large size pipeline,the welding method has the disadvantages of difficult to operate,low efficiency,high energy consumption and accompanied by environmental pollution and other shortcomings.Pipeline mechanical connection mode has many advantages,such as easy installation,easy replacement and less influence by water depth,and has been paid more attention in recent years.A set of hydro-telescoping mechanical connector used in this study is a new type of pipe connector,which is suitable for deepwater area with depth of 1500 meters.It has the advantages of higher fatigue resistance,no rotation,faster installation than thread connection,and higher strength than in-situ welding.For the installation and operation of pipe type structure of deepwater offshore platform is complicated,and the range of size series is wide and there is a lack of rapid design and optimization analytical model for hydro-tetecoping mechanical connector.This paper makes research on it from the following aspects.Firstly,based on the analysis of connection requirements,the structural scheme and installation process of mechanical connectors are described,and the structural parameters of mechanical connector are planned.Considering the actual operation requirements and the installation process of connectors,the mechanics model of the whole part of the connector and the tooth shape of the main bearing part are described.The installation requirements for the proper installation of the connector and the conditions that the internal pressure should be satisfied are put forward.Secondly,based on the mechanics model of connector,proposed the optimization mathematical model to determine the key parameters of the mechanical structure,the optimization objective is to meet the stress intensity and installation requirements,get the smallest overall weight of the structure parameters.For the optimization model,three optimization algorithms are adopted: the nonlinear programming algorithm,the genetic algorithm and the nonlinear programming genetic algorithm,and the structural parameters of the mechanical connector are obtained.The optimization process of the three algorithms is compared,and the results show that the nonlinear programming genetic algorithm is the best choice to solve the model.Thirdly,the parametric modeling process of mechanical connector in Creo 3D modeling software is introduced.The condition that connector needs to be installed and used is put forward.The establishment of three-dimensional model of mechanical connector with optimized parameters,the model is imported into Abaqus software,the connector is simulated under the condition of installation and the condition of use The results show that the optimized parameters can meet the requirements.Considering the three different modeling methods,the finite element simulation of the connector is compared,and a better modeling method is obtained by comparing the results.Considering the change of installation thickness at the transition arc,the simulation of the connector was carried out,and the installation rule influenced by transition arc thickness was obtained.Finally,considering the actual operation requirement of mechanical connector used in TLP tethers,the fatigue analysis is done.Using Creo modeling into AQWA,the hydrodynamic analysis of the TLP platform is carried out and the load spectrum at the junction of the top and the platform is obtained.With the load spectrum,the static analysis of ABAQUS is carried out to get the hot spot that connectors are easy to fatigue.According to the fatigue hot spots,based on S-N curve and Miner cumulative damage theory,the fatigue cumulative damage and fatigue life of the connector are calculated.The results show that the fatigue life and fatigue damage of the connector hot spot meet the requirements.更多还原