Dynamic analysis of multibodies system with a floating base for rolling of ro-ro ship caused by wave and slip of heavy load

Common effect of wave and slip of internal heavy load will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibodies System with a floating base is composed of ro-ro ship and slipping heavy load. This paper takes the rolling angle of the ship and the transverse displacement of the heavy load on desk as two freedoms. Making use of analysis of apparent gravitation and apparent buoyaney, the wave rolling moment is derived. By use of dynamic method of multibodies system with a floating base, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the ship and displacement response of the slipping heavy load under common effect of synchro-slipping heavy loads and wave.     

英文导读

<正> Dear readers: Extremely high temperature is overwhelming large part of east coast of the country in July and August this year, the campaign for better understanding of "Law of Ports" sees even more highlighted. Ministry of Communications has timely held a special meeting in Shenzhen for deeply implementing of "Law of Ports" where Mr. Hong Shanxiang of Deputy Minister of MOC and Ms. Peng Cuihong, Deputy Director-General of Water Transportation Dept. of MOC gave a keynote speeches and relevant instructions. Mr. Su Xingang, Director-General of Water Transportation Dept. of MOC has also given a summary at the meeting. This issue publishes their speeches in attempt to properly consolidate implementation of "Law of Ports" by grassroots units. Our magazine will     

Analysis of motion on agile shell-feeding system

Since cannon drum of agile shell-feeding system rotates frequently and intermittently, its motion must be steady. Outline of driving cam determines the motion of cannon drum, so it is necessary to select the proper outline of cam. Through analysis of parabolic outline and cycloid outline of the cams, the outline that combines the two curves is obtained. According to the demand of production, the value of the outline is revised, and then the method of fitting curve is used to get the expression of the angle of cam and the displacement of the driven part. Through analyzing the motion of the cannon drum, it is suggested that the angle of the cam is proportion to the displacement of the driven part. The cam with the specially derived outline can move steadily.     

DEVELOP INTERNATIONAL ECONOMIC & TECHNICAL EXCHANGES AND PROMOTE COOPERATION BETWEEN CHINA SHIPBUILDERS AND THEIR FOREIGN COUNTERPARTS

On the occasion of the opening of China shen-zhen Technology Fair,I,on behalf of China ship-building Technology Transaction Delegation,ex-press our hearty welcome to all of our friends com-ing from many parts of the world to this Fair!Acting as the backbone of the shipbuilding in-dustry of China and pursuing a policy of"DomesticFirst,Keen on Export;shipbuilding First,BusinessDiversified",thc China State shipbuilding Corpora-tion(CSSC)has made significant contributions tothe modernization of the national defense,moder-nization of transportation,development of offshore     

Application of LES in the study of inlet flow field in marine gas turbine

The structure and aerodynamics performance of gas turbine inlet system is an important part of technology of gas turbine installed on naval vessels. The design and numerical simulations of gas turbine inlet system are conducted and reliable foundation for design and manufacture of marine gas turbine inlet system of high performance is provided. Numerical simulations and experiments of two inlet system models of gas turbine are conducted with satisfactory results and are of significance to the actual application of the inlet system.     

舰船刚性阻振质量复合托板隔振特性优化设计(英文)

In considering the theory of structural dynamic optimization design, a design method of the structural style of ship composite brace with rigid vibration isolation mass was studied. Two kinds of structural dynamic optimization formulations minimizing the vibration acceleration of the non-pressure hull on the restraining condition of the gross weight of the ship cabin were established: 1) dynamic optimization of the sectional dimensions of the rigid vibration isolation mass in the composite brace; 2) dynamic optimization of the arranging position of the rigid vibration isolation mass. Through the optimization results, sectional dimensions and the arranging position of the rigid vibration isolation mass with better performance in reducing vibration were gained, and some reference was provided for practical engineering designs as well as enrichment of the design method of a novel ship vibration-isolation brace.     

Numerical simulation on truncated oval-nosed projectile penetrating into stiffened plate北大核心CSCD

[Objectives]In this paper, the numerical simulation method is used to study the anti-penetration performance and energy absorption mode of a stiffened plate, as well as the influence of different stiffened bars on the flight attitude of the projectile body.[Methods] Finite element software LS-DYNA is used to simulate the process of a truncated oval-nosed projectile penetrating a stiffened plate, and the results of the numerical simulation are compared with an experiment to verify the reliability of the numerical simulation method. The momentum method and mass equivalence method are used to predict the residual velocity of the projectile, and the applicability of different theoretical methods within different velocity ranges is compared. The deformation energy of different regions of the stiffened plate is then extracted to analyze the influence of the initial velocity of the projectile body on the energy absorption mode of the target plate. Finally, the structure of the stiffeners is changed and the influence of the relative position of the stiffeners on the penetration attitude of the projectile body is analyzed.[Results]The results show that the mass equivalence method is more accurate than the momentum method in predicting the residual velocity of the stiffened plate when the initial velocity of the projectile body is in the range of 300–900 m/s. The ratio of the deformation energy of the stiffened plate to the energy loss of the projectile body decreases with the increase of the initial velocity of the projectile body. The effect of a T-stiffened plate on trajectory is greater than that of a rectangular-stiffened plate.[Conclusions]The related calculation method and research results have certain reference value for research and engineering application surrounding the anti-penetration of stiffened plates. © 2023 Chinese Journal of Ship Research. All rights reserved.     

Logistics should go ahead of developing west China

With the State Council's decision to implement itsstrategy of developing West China,the development of West Chinahas become one of the new hot points in the development of China'seconomy.In the meantime,it provides China's industry of logisticswith a new developing opportunity.For this,Professor WangZhitai,member of the Chinese People's Political ConsultativeConference and Director of Logistics Committee of ChinaNational Association of Material and EquipmentTrade,has put forward his original view.     

Analysis of deformation of rotor and influence on the performance of gyro based on B-spline wavelet FEM

Some construct characteristics and composing material of the new Gyro＇ s rotor are introduced. Some factors resulting in deformation of the rotor surface are analyzed. Under different loads such as the fo,＇ce of deflecting center, the change of temperature, the fo,ce of pressure and couple factors, the deformation of rotor is analyzed with the wavelet finite element simulation software. The vector distributing map of rotor reformation is given. The deformation resulting from the pressure force of photon is studied. Finally, the influence on Gyro＇ s performance because of anomalous surface of rotor due to deformation of rotor is researched and the result is useful to forecast the performance of the drift of gyroscope. The disturbing moment resulting from the deformation of rotor can be compensated using the mathematic method, and provides an important reference for both design and optimization of the rotor.     

INFORMATION

MoU signed On April 11, 2001, Minister of the Ministry of Communications Huang Zhendong held talks with the Honourable John Anderson MP, Deputy Prime Minister and Minister for the Department of Transport and Regional Services of Australia, and signed a Memorandum of Understanding (MoU) between the Department of Transport and Regional Services of Australia and the Ministry of     

Scattering of surface water waves involving semi-infinite floating elastic plates on water of finite depth

Two problems of scattering of surface water waves involving a semi-infinite elastic plate and a pair of semi-infinite elastic plates,separated by a gap of finite width,floating horizontally on water of finite depth,are investigated in the present work for a two-dimensional time-harmonic case.Within the frame of linear water wave theory,the solutions of the two boundary value problems under consideration have been represented in the forms of eigenfunction expansions.Approximate values of the reflection and transmission coefficients are obtained by solving an over-determined system of linear algebraic equations in each problem.In both the problems,the method of least squares as well as the singular value decomposition have been employed and tables of numerical values of the reflection and transmission coefficients are presented for specific choices of the parameters for modelling the elastic plates.Our main aim is to check the energy balance relation in each problem which plays a very important role in the present approach of solutions of mixed boundary value problems involving Laplace equations.The main advantage of the present approach of solutions is that the results for the values of reflection and transmission coefficients obtained by using both the methods are found to satisfy the energy-balance relations associated with the respective scattering problems under consideration.The absolute values of the reflection and transmission coefficients are presented graphically against different values of the wave numbers.     

纵向弯矩下材料随机特性对复合材料船体可靠性的影响

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging.The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling,material failure,and ultimate collapse) were calculated by the surface response method and JC method.The importance factors of random variables in stochastic models,such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands,as well as the stochastic characteristics of materials in the models used,were calculated.Then,the effects of these random variables,including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging,were discussed with their importance factors.The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships.Finally,some conclusions and recommendations were given for high-speed ship design and safety assessment.     

CCS:Pioneer for LNG Ship Standard

Although China is relatively late in the trial use of LNG ships,she has become the front runner in the promotion of LNG ships.The launch of China’s first LNG/diesel hybrid pilot inland waterway ship in 2010 became the prelude for the application of LNG as bunker fuel for water transportation.At present,with the speeding up of the layout of LNG stations of energy companies,and the increase of the government’s policy support,there is the trend of fast development of"oil converted to     

CFD simulation of the vertical motion characteristics of the moonpool fluid for the truss spar

The research purpose of this paper is to estimate theimpacts of the parameters of the guide plate on the vertical motioncharacteristics of the moonpool fluid. With the volume of fluid（VOF） method, three-dimensional models of the moonpool fluidmotions of the truss spar platform are established. Simulationresults are then presented for the moonpool forced oscillation byemploying the dynamic mesh method and user-defined functions inFLUENT. The motions of the moonpool fluid and the loads on theguide plates are obtained for both cases of square-ring andcrisscross. The results show that the shape and area of the guideplate at the bottom of the moonpool have a significant impact onthe physical parameters of the moonpool, including the load on themoonpool guide plate, motion form of the moonpool fluid and themass flow rate.     

Analysis and experiment of a vessels shell cover in submarine structure

This paper aims to achieve analysis and experiment results that relate to mechanics capability and structural parameter of a special saddle shell of revolution. Theoretically speaking, the saddle shell of revolution consists of a toroidal shell and a spherical shell. The shells simultaneous equations can he solved with harmonious terms. Where, the fundamental equations can be solved by asymptotic exponential perturbation method. The equations of special solution can be solved by Hovozhilovs special solution. This new idea is from a study of some existing solutions of the toroidal shell. The results have heen proved by eompared with some experimental results. The experiments aims to study the effect caused by change of material parameter,or by change of different geometrie dimensions of the saddle shell,which include the ehange of thickness, the change of radius of shell, and the change of ribs. Finally, the accepted product of the saddle shell were reinforeed by a toroidal rib has been submitted.     

Strength reliability analysis of stiffened cylindrical shells considering failure correlation

The stiffened cylindrical shell is commonly used for thepressure hull of submersibles and the legs of offshore platforms.There are various failure modes because of uncertainty with thestructural size and material properties, uncertainty of the calculationmodel and machining errors. Correlations among failure modesmust be considered with the structural reliability of stiffenedcylindrical shells. However, the traditional method cannot considerthe correlations effectively. The aim of this study is to present amethod of reliability analysis for stiffened cylindrical shells whichconsiders the correlations among failure modes. Firstly, the jointfailure probability calculation formula of two related failure modesis derived through use of the 2D joint probability density function.Secondly, the full probability formula of the tandem structuralsystem is given with consideration to the correlations among failuremodes. At last, the accuracy of the system reliability calculation isverified through use of the Monte Carlo simulation. Result of theanalysis shows the failure probability of stiffened cylindrical shellscan be gained through adding the failure probability of each mode.     

Analysis on Uncertain Information and Actions for Preventing Collision

Discusses and analyzes the causes and characteristics of the uncertainties of the information and actions for preventing collision at sea on the basic knowledge of the collision avoidance.Describes the ways and functions of the investigations about the uncertainties of the information and actions of collision avoidance with the navigation simulators.Puts forward some suggestions for the officers to master the skills of the recognition of these uncertainties of the information and actions by the training with the sim- ulator during the MET course.     

Reader's Guide

<正>Dear readers:Early autumn in August symbolizes end of hot summer soon that however imposes no influence on portbusiness and witnesses triumphant news instead.This edition therefore presents a special report of"Status of E-conomic Performance at First Half of 2004,and Analysis on Trends at Second Half of the Year" that proves anauthorized information by Department of Water Transportation of Ministry of Communications.The report advis-     

Analysis of mathematical model for micromechanical vibratory wheel gyroscope

By the sketch of structure of MVWG,the working laws of this kind of gyroscope were explained. To the aid of Euler‘‘s Dynamics Equation,a mathematical model of the gyroscope was constructed, and then by the basic working laws of MVWG the model was simplified. Under the conditions of the three axial direction rotations and general rotation, the mathematical model was resolved. And finally by the solutions, the working laws of the gyroscope, the working disparity among all sorts of gyrations and the influences from the gyrations in the axial directions were analysed.