一流的境界 一流的技艺 一流的素质

2004年6月11日，中元集团职工素质工程推进暨中央企业职工素质工程现场观摩会在在天津隆重举行，国务院国有资产监督管理委员会副主任王瑞祥。劳动和社会保障部，全国总工会，天津市总工会有关领导及国资委监管的100多家中央企业的代表莅临现场观摩。     

东京的船的科学馆

在东京，由全日本动力艇模型联盟的朋友陪同参观了船的科学馆，日文名为“船の科学馆”．英文写作“Museum of maritime science”，似可译成“海运科学馆”。     

一流的境界一流的技艺一流的素质

2004年6月11日,中远集团职工素质工程推进会暨中央企业职工素质工程现场观摩会在天津隆重举行.国务院国有资产监督管理委员会副主任王瑞祥、劳动和社会保障部、全国总工会、天津市总工会有关领导及国资委监管的100多家中央企业的代表莅临现场观摩.     

海的梦船的梦

一、开关产品和船模似乎风马牛不相及 我应浙江宁波宁海县县委邀请,去参观访问,猜不透宁海宣传部为什么要带我到大佳何镇去？为什么要参观一个制造开关和金属零件的工厂？此厂的门而并不气派,厂房的规模不大,设备也不现代化,甚至还有手工制作的痕迹。那么,难道是这个厂生产的开关和金属制品出类拔萃？也不是．很一般,很平常,成品就在道旁,包装简单,堆放得也不整齐划一。     

基于PWM的疲劳试验机的激励系统的设计

激励系统是疲劳试验机的重要组成部分,本文依据PWM的基本原理,提出了一种简单、实用的激励系统的设计方案:运用脉冲宽度调制芯片SG3525AN把输入的正弦波信号转换为PWM波,再通过MOSFET驱动芯片LM5101进行放大等处理去控制功率MOSFET的通、断,从而实现输入信号的功率放大。该方案电路结构简单、效率高,工作可靠,能够满足大部分疲劳试验机的需求。     

古老的行业 崭新的技术 强大的竞争优势

海上航行是连接世界各国文化，经济，技术交流的传统纽带。通过海上航行世界各国人民达到了相互了解，相互补充，促进了世界政治，经济的发展。     

基于改进的神经网络的船舶碰撞危险度的模型

针对船舶碰撞危险度具有模糊性、不确定性等特点,依据模糊理论方法建立的船舶碰撞危险度的数学模型,直接采用来船航速、来船航向、来船对本船的相对舷角和来船对本船距离作为神经网络的输入,采用Levenberg-Mrquardt优化算法这种改进的BP神经网络进行训练和仿真,并与标准BP算法和动量BP算法进行比较,发现经过改进的网络求得碰撞危险度比标准BP算法和动量BP算法具有更好的效果,网络能够更有效收敛,大大提高了网络的收敛速度和泛化能力。     

科学的思维神圣的职责

为期9天半的第十届全国人大二次会议已于3月14日闭幕.全国人大代表、中远(集团)总公司党组书记张富生出席了此次会议.会议期间,作为辽宁省代表团成员、大型航运企业领导,张富生书记向人大共提交了三个议案和三条建议:     

全新的环境 更高的起点

经历了15年的艰苦谈判,我国终于成功地加入了世界贸易组织(WTO).它标志着我国改革开放实现了又一次重大跨越.迈出这一步,意味着我国将更紧密、更深入地融入经济全球化和世界经贸大市场,社会主义市场经济进入了新的发展阶段.     

Wave impact underneath horizontal decks

The problem of water impact on a fixed horizontal platform deck from regular incident waves was studied. Two-dimensional potential flow was assumed, and the resulting boundary-value problem was solved by three alternative numerical methods, a method based on a generalization of the impact theory by Wagner, and two different nonlinear boundary-element methods. The Wagner-based method used a von Karman approach during the water exit phase, i.e., when the wetted surface decreases. Experiments of the impact on an idealized platform deck have been performed to validate the theory. Comparisons show that the Wagner-based method yields good results for the water entry phase, when the wetted deck area increases, but poor results when the wetted area diminishes. The boundary-element methods compare well with experiments for the entire impact process. A Kutta condition is necessary at the aft body–free surface intersection during water exit and when the flow separates from the aft edge. Gravity effects matter for the water exit phase.     

甲板上浪问题的二维数值模拟

以连续性方程和N-S方程为控制方程,采用源造波理论和技术,建立了具有造波和消波功能的二维数值波浪水槽,并使用VOF方法追踪自由面来模拟二维情况下的甲板上浪问题.文中就迎浪状态下的固定FPSO和横浪状态下的运动船体断面模型所遭遇的甲板上浪现象分别进行了数值模拟研究.船体的运动规律通过势流理论计算结果给定,在上浪现象模拟计算时,船体的运动采用移动网格技术实现.研究表明,计算结果与试验结果相当吻合,该方法可以用于甲板上浪现象的预报和模拟,可以用于分析预报甲板上浪对浮体的破坏作用.     

规则波对弹性支承水平板冲击压力的概率分析

通过模型试验研究了规则波对弹性支承水平板冲击压力峰值的概率分布。文中通过对不同组次的试验数据进行统计分析,首先给出了弹性支承与刚性支撑之间水平板波浪冲击压力历时曲线的各自特征;其次研究了弹性支承水平板波浪冲击压力峰值的超值概率分布及拟合曲线和参数;最后讨论了弹性支承刚度与威布尔分布三参数之间的关系。     

Numerical simulation of wave-induced nonlinear motions of a two-dimensional floating body by the moving particle semi-implicit method

The moving particle semi-implicit (MPS) method was applied to compute nonlinear motions of a floating body influenced by the water on deck. To compute the motions of a rigid body, the fluid pressure at the position of each particle on the body surface was directly integrated in space and the equations of translational and rotational motions were integrated in time to determine the correct position of the rigid-body surface at each time step of the time-domain calculation. The performance of this method was validated through a comparison with measured results in an experiment that was newly conducted using a model of a box-shaped floating body with a small freeboard. Although the overall agreement was good, some discrepancies were observed for a shorter wave period, especially for the drift motion in sway. The effect of numerical resolution on the results was checked by changing the number of particles. With a higher number of particles, no obvious improvement was seen in the global body motions, but the resolution of the local free-surface profile, including the water on deck, was improved.     

规则波作用下近岸透空式结构物的波浪上托力研究

基于对透空码头结构物波浪上托力研究现状的分析,运用垂向二维CFD数值波浪水槽建立模拟规则波作用下水平板波浪上托力的数值模型.通过物理模型和数值模型所获波浪压力结果的对比分析,总结平板底部流场和测点压强的分布特点,探讨不同周期波浪的最大冲击压强随波浪相对超高变化的规律.试验结果表明,规则波作用下波浪上托力的数值模拟结果与...     

Green water loading on a floating structure with degree of freedom effects

The aim of the present work is to investigate whether the degree of freedom (DOF) of a floating body has a notable effect on the maximum impact pressure due to green water on deck. The analysis is carried out for a box-shaped floating structure with a deckhouse, using experimental and numerical means to model the green water load. Green water on deck and impact on the deckhouse is generated by the impingement of a focusing wave group on a floating structure. Computations are performed using a two-dimensional constrained interpolation profile-based model solving the Navier–Stokes (N–S) equations with free surface boundary condition to deal with nonlinear water–structure interactions. The free surface is captured by a volume of fluid (VOF)-type tangent of hyperbola for interface capturing/slope weighting (THINC/SW), which is more accurate than the original THINC scheme. The verifications of the simulation through a series of model-to-model comparisons are performed in a two-dimensional glass-wall wave tank. Experimental water surface elevations, body motions and impact pressure are compared satisfactorily with the computed results for different DOFs cases. As a result, the peak impact pressure due to green water decreases rapidly with the increasing DOF.     

溃坝问题的数值仿真和实验(英文)

In this paper, two novel numerical computation methods are introduced which have been recently developed at Research Institute for Applied Mechanics ( RIAM ), Kyushu University, for strongly nonlinear wave-body interaction problems, such as ship motions in rough seas and resulting green-water impact on deck. The first method is the CIP-based Cartesian grid method, in which the free surface flow is treated as a multi-phase flow which is solved using a Cartesian grid. The second method is the MPS method, which is a so-called particle method and hence no grid is used. The features and calculation procedures of these numerical methods are described. One validation computation against a newly conducted experiment on a dam break problem, which is also described in this paper, is presented.     

Three-dimensional numerical analysis of shipping water onto a moving ship using a particle method

The objective of this study was to develop a numerical analysis method based on the moving particle semi-implicit method for simulating shipping water on a moving ship. Towing tests of a very large crude carrier were numerically analyzed for three typical wavelengths. The ship was forced to move in order to express previously measured ship oscillations, and the calculated fluid behavior and the impact pressure on the deck were compared with the experimental results.     

浮体升沉和纵摇运动对甲板上浪载荷影响数值研究（英文）

In this paper, the influence of heave and pitch motions on green water impact on the deck is numerically investigated. The vessel motions are determined using a potential theory based method and provided as input to finite volume based CFD computations of green water phenomenon. A dynamic mesh approach is adopted to determine instantaneous body positioning in the fluid domain.Detailed validation studies with published experimental results for 2D and 3D fixed vessel cases are initially performed to validate the present numerical approach before studying the moving vessel problem. The results show that inclusion of heave and pitch motion changes the disturbed wave field near the bow which influences the free surface as well as the impact loading due to green water. The effect of wave steepness on green water impact is also investigated and it is seen that the present numerical method is capable of capturing green water load. It is observed that the effects of vessel motions on green water load are not negligible and one should consider this effect too. The incorporation of vessel motions in the vertical plane affects the green water loading on the deck.     

Research on the dynamic buckling of a typical deck grillage structure subjected to in-plane impact Load

The dynamic buckling of the main deck grillage would result in the total collapse of the ship hull subjected to a far-filed underwater explosion. This dynamic buckling is mainly due to the dynamic moment of the ship hull when the ship hull experiences a sudden movement under impact load from the explosion. In order to investigate the ultimate strength of a typical deck grillage under quasi-static and dynamic in-plane compressive load, a structure model, in which the real constrained condition of the deck grillage was taken into consideration, was designed and manufactured. The quasi-static ultimate strength and damage mode of the deck grillage under in-plane compressive load was experimentally investigated. The Finite Element Method (FEM) was employed to predict the ultimate strength of the deck grillage subjected to quasi-static in-plane compressive load, and was validated by comparing the results from experimental tests and numerical simulations. In addition, the numerical simulations of dynamic buckling of the same model under in-plane impact load was performed, in which the influences of the load amplitude and the frequency of dynamic impact load, as well as the initial stress and deflection induced by wave load on the ultimate strength and failure mode were investigated. The results show that the dynamic buckling mode is quite different from the failure mode of the structure subjected to quasi-static in-plane compressive load. The displacements of deck edge in the vertical direction and the axial displacements are getting larger with the decrease of impact frequency. Besides, it is found that the dynamic buckling strength roughly linearly decreased with the increase of initial proportion of the static ultimate strength P₀. The conclusions drawn from the researches of this paper would help better designing of the ship structure under impact loads.