Sea trials of Sigma wave energy converter – slacking and snapping of TLP mooring lines

Sigma Energy has performed its foremost prototype tests of scaled wave energy converter in a real sea environment. The prototype was a point absorber with a cylindrical buoy, a mechanical power take-off system with a counterweight, moored to the seabed as a tension leg platform (TLP) with three equal tendons. In these extensive experiments, numerous device characteristics were measured and analysed. The present paper focuses on the dynamic forces in the mooring lines, and some unexpected and rare data obtained. It is well known that TLP tendons are prone to a brief loss of tension (the slacking) and that, after such events, high snapping forces of short duration can arise. Partly by intention, and partly due to underestimation of the dynamical forces, several such slacking-snapping incidents were recorded during the experiments. In some severe storms, the snapping forces were up to six times higher than the tendon pretension. The paper presents several recordings of dynamic forces and platform motion during these critical events. It analysis them, and gives a typical scenario under which they occur. It gives also some theoretical explanations, and numerical predictions of dynamical tendon forces, with their comparison to the experimental results.     

机器人智能焊接技术在甲板片体框架结构上的应用

针对甲板片体框架结构特点和机器人智能化焊接工艺要求，在合理的甲板片体分段划分基础上，综合运用机器人智能控制、离线编程、焊接工艺数据库和视觉识别等技术，完善机器人焊接作业流程，优化机器人焊接分段作业顺序，提高机器人焊接可达性，可进一步提高甲板片体框架结构机器人智能焊接技术应用水平。     

浮式平台上部模块非管节点SCF控制方法

应力集中系数（Stress Concentration Factor，SCF）是评估节点疲劳损伤的重要参数。针对浮式平台上部模块非管节点的SCF控制，设计5种加强形式，采用Ansys软件对非管节点进行SCF分析。结果表明：筋板加强可有效改善面外弯矩作用下的应力集中；扣管加强对轴向力、面内弯矩和面外弯矩均具有较好的改善效果。     

基于SVG格式的远洋客船电子地图显示模块构建

对可缩放矢量图形（Scalable Vector Graphics，SVG）技术特点进行分析，结合远洋客船电子地图显示模块功能需求，对电子地图进行功能设计，实现远洋客船电子地图显示模块的构建。以某远洋客船为例，验证基于SVG格式的电子地图显示模块符合远洋客船网络化构建的需求，可为后续远洋客船实现乘员动态导航和构建个性化网络服务平台提供技术基础。     

Efficient time-domain approach for hydroelastic-structural analysis including hydrodynamic pressure distribution on a moored SFT

This study investigates the hydroelastic analysis of a moored SFT (submerged floating tunnel) and the corresponding hydrodynamic pressure distribution under wave excitations. Time-domain discrete-module-beam (DMB) method, in which an elastic structure is modeled by multiple sub-bodies with beam elements, is employed to express the deformable tunnel with multiple mooring lines. Moreover, the top-down scheme is also adopted for detailed structure analyses with less computational cost, which applies the calculated hydrodynamic pressure distribution over SFT's surface to the three-dimensional finite element model. The hydrodynamic pressure includes both wave-induced diffraction pressure and motion-induced radiation pressure. For the validation of the developed numerical approach, comparisons are made with computationally intensive hydroelastic-structural direct-coupled method, two-dimensional wave flume experiment, and independently developed inhouse moored-SFT-simulation program. Furthermore, the influences of flexural motions with buoyancy-weight ratio (BWR) (or bending stiffness) and regular/irregular wave conditions on the dynamic pressure distribution and the resulting local stresses are investigated.     

中型豪华邮船舱室模块吊运工装有限元分析

针对邮船舱室模块缺少强框架支持和易产生吊装变形等问题，对比4种常见的舱室模块吊装方式，分析在吊装过程中舱室模块容易变形的原因。以某中型豪华邮船舱室模块为例，设计一种吊运工装，利用有限元分析方法，计算吊运工装在不同工况条件下的结构强度和结构变形，并对其进行优化。结果表明，优化的吊运工装其结构强度满足中型豪华邮船舱室模块的吊装需求，可减少舱室吊装变形，提升船厂舱室模块吊装的安全性和高效性。