渤海地区平台结构设计环境条件选取分析

随着平台的使用年限增长,环境条件随着海洋环境的变化而变得日益恶劣,对于渤海地区,提出了是否采用100年一遇环境条件替换50年一遇环境条件进行结构设计.经过对渤海地区的部分中心平台和井口平台50年/100年环境条件对比分析,提出了对于渤海地区海上平台结构采用100年一遇环境条件替换50年一遇环境条件.     

水下多路液压快速接头的夹头结构分析与优化

深海油气田水下生产系统装备之间的精准连接是国际公认的技术难题,对接一般通过深海连接器完成。弹性夹头是水下连接器的重要组成部分,其性能关系到海洋油气生产系统的安全性和可靠性。弹性夹头的主要作用是在水下机器人的辅助下连接和锁紧连接器的固定端和移动端。采用ABAQUS软件的显式动力学分析模块计算夹头夹紧心轴这一过程中的应力、反作用力状态。三维模型仿真结果表明,锁紧过程中弹性夹头的最大应力不超过430 MPa,小于所选取的材料屈服强度480 MPa。采用正交试验和方差分析的方法研究夹头的长度、夹头与心轴的间隙等几个关键尺寸从而分析影响夹头应力和连接所需推力的最显著因素。对夹头的结构进行优化设计,同时也为夹头心轴结构的设计提供了理论依据。最后,通过试验研究对样机进行测试,测试结果表明,夹紧动作所需的最大推力在700 N以下。     

Developing a building policy for the erosion zone: Solutions to some key (Dutch) questions

In those coastal communities where the most seaward strip of mainland consists of dunes, these dunes often serve as a flexible sea defence. In addition, this strip offers large potential for housing and commercial enterprises. Unfortunately, due to severe storm surges part of this strip (the erosion zone) is subject to erosion, and as a result of which any buildings or infrastructure located here, are destroyed. Therefore, as we will illustrate in this paper, a building policy for this zone should reflect a compromise between two opposite interests: exploitation of the existing potential and, prevention of an unacceptable high risk due to erosion. Accordingly, the authors have developed a framework for such a building policy on the basis of which the desirability of various different types of investments and the location within the erosion zone of such investments can be determined. The examples that are used to illustrate this framework in this paper are limited to experiences in The Netherlands as relevant data and experiences are available and relatively easy accessible here. Nevertheless, the approach as is described is generic and applicable worldwide suggesting that the discovered unused potential for exploitation is not just limited to The Netherlands.     

Numerical simulation of sloshing waves in a 3D tank based on a finite element method

The sloshing waves in a three dimensional (3D) tank are analysed using a finite element method based on the fully non-linear wave potential theory. When the tank is undergoing two dimensional (2D) motion, the calculated results are found to be in very good agreement with other published data. Extensive calculation has been made for the tank in 3D motion. As in 2D motion, in addition to normal standing waves, travelling waves and bores are also observed. It is found that high pressures occur in various circumstances, which could have important implications for many engineering designs.     

The Optimal Design of TMD for Offshore Structures

This paper presents the optimal design procedure of Tuned Mass Damper(TMD)for re-ducing vibration of an actual steel jacket offshore platform excited by random wave loading.In this study,a frequency domain is taken.The force on the structure is determined by use of the linearized Morisonequation for an input Power Spectral Density(PSD)of wave elevation.The sensitivity of optimum valuesof TMD to characteristic parameters of random wave spectrum is analyzed.An optimized TMD designfor the modeled platform is given based on design conditions and the findings of the study.     

Improved assessments of wave-induced fatigue for free spanning pipelines

For subsea pipeline projects, the costs related to seabed correction and free span intervention are often considerable. Development of reliable methods for fatigue analyses of pipelines in free spans contributes to minimize costs without compromising pipeline integrity. Assessment of wave-induced fatigue damage on multi-span pipelines is investigated, and improved analysis methods are suggested in this paper. A time-domain (TD) algorithm is developed, which accounts for non-linear hydrodynamic loading and dynamic interaction between adjacent spans. The proposed TD approach is employed to evaluate linearized frequency-domain (FD) solutions from recognized design standards and to study the dynamic response of multi-span pipelines to direct wave loading. Differences between multi- and single-span analyses are described for the first time, and the common assumption that the main fatigue damage contribution comes from the fundamental mode is demonstrated not to hold for multi-spans. An improved FD solution capable of predicting multi-mode response is derived and demonstrated to give accurate fatigue life estimates for multi-span pipelines.     

海洋地球物理数据库设计与实现

在对海洋地球物理数据类型和特点进行分析的基础上,从海洋地球物理元数据、基础数据库和空间数据仓库等几个方面对海洋地球物理数据库进行设计,并基于C/S和B/S架构开发了海洋地球物理数据库管理系统。经应用实践,该系统能够实现海洋地球物理数据的高效化管理和便捷化共享,提高了数据的使用效率,满足海洋调查、科研、管理等工作的需求。     

Numerical and Experimental Analysis of A Ducted Propeller Designed by A Fully Automated Optimization Process Under Open Water Condition

A fully automated optimization process is provided for the design of ducted propellers under open water conditions, including 3D geometry modeling, meshing, optimization algorithm and CFD analysis techniques. The developed process allows the direct integration of a RANSE solver in the design stage. A practical ducted propeller design case study is carried out for validation. Numerical simulations and open water tests are fulfilled and proved that the optimum ducted propeller improves hydrodynamic performance as predicted.     

大深度救生钟耐压结构的优化设计

针对某型救生钟的救生舱耐压壳体,推导出典型水下耐压结构的计算公式,建立结构优化数学模型,并编制计算程序以求解结构最优尺寸,在此基础上确定耐压结构的设计尺寸.对设计结果采用有限元计算和规范计算比对分析,结果证明采用程序计算设计的优化尺寸满足工程要求.本文提供的计算方法可为水下环肋耐压壳体结构工程设计提供参考.