检索结果-南通市图书馆

A new subregion mesh method for the investigation of the elastic-plastic impact in flexible multibody systems

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2017年第1期33卷 189-199页

作者： Peng Chen Jin-Yang Liu Guang-Can Lu Department of engineering Mechanics School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200240 China

Impact processes between flexible bodies often lead to local stress concentration and wave propagation of high frequency. Therefore, the modeling of flexible multibody systems involving impact should consider the local plastic deformation and the strict requirements of the spatial discretization. Owing to the nonlinearity of the stiffness matrix, the reduction of the element number is extremely important. For the contact-impact problem, since different regions have different requirements regarding the element size, a new subregion mesh method is proposed to reduce the number of the unnecessary elements. A dynamic model for flexible multibody systems with elastic-plastic contact impact is established based on a floating frame of reference formulation and complete Lagrange incremental nonlinear finite-element method to investigate the effect of the elastic-plastic deformation as well as spatial discretization. Experiments on the impact between two bodies are carried out to validate the correctness of the elastic-plastic model. The proposed formulation is applied to a slider-crank system with elastic-plastic impact.

关键词： Multibody dynamics Elastic-plastic impact Subregion mesh method Experiment

OPTIMIZING LAYOUT OF URBAN STREET CANYON USING NUMERICAL SIMULATION COUPLING WITH MATHEMATICAL OPTIMIZATION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第3期18卷 345-351页

作者： WANG Jia-song ZHAO Bao-qing YE Chun YANG De-qing HUANG Zhen school of Mechanical and Power engineering Shanghai Jiaotong University Shanghai 200030 China school of naval architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200030China

Optimizing the layout of the urban street canyon to achieve the maximum environmental benefits should become a new idea for modem urban street design and planning. This paper aims to find out the optimized street canyon from a viewpoint of environmental protection by using the two-dimensional numerical simulation model with the κ-ω turbulence model, coupling with the mathematical optimization method. The total pollutant concentration within and at top of the specific street canyons was taken as the objective function, and the height of one side of the canyon as the constrained condition. A nonlinearly improved constrained variable metric solver was used. The effect of the height of the leeward building and windward building on the integrated pollutant dispersion was studied to achieve the most beneficial configuration of the urban geometry. The optimization of layout for an asymmetrical street canyon was obtained. It is further found that the step-down street canyon with a large height difference is generally a good layout favoring to reduce the concentration accumulation in the street canyon.

关键词： street canyon mathematical optimization numerical simulation street layout

Waves scattering induced by an interface crack in a coated material

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang university-Science A(Applied Physics & engineering) 2005年第9期6卷 950-955页

作者：常军刘勇许金泉 school of naval architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200240 China

This paper deals with the two-dimensional problem of elastic wave scattering from a finite crack at the interface between a coated material layer and its substrate. By adopting the Fourier transform method and introducing the crack opening displacement function, the boundary value problem is simplified for numerically solving a system of Cauchy-type singular integral equations by means of Jacobi polynomial expansion. The stress intensity factors and the crack opening displacements are defined in terms of the integral equations solutions. The influence of the dimensionless wave number and the ratio of crack length to layer thickness on the stress intensity factors and crack opening displacements are discussed.

关键词： Wave scattering lnterfacial crack Coated materials

An Analysis on Limit Load for Corroded Submarine Pipelines

在线全文

学校读者我要写书评

暂无评论

China ocean engineering 2006年第3期20卷 483-490页

作者：谭开忍肖熙 school of naval architecture ocean and Civil engineering Shanghai JiaoTong University Shanghai 200030 China

By means of elastic-plastic finite element analysis, a systematic nonlinear analysis of material and geometry has been carried out for submarine pipelines. A criterion for deriving limit load is studied. Based on this criterion, the limit load for corroded submarine pipelines is calculated. The corrosion length, corrosion depth and corrosion width affect the limit load. A solution to limit load is proposed and proved valid through comparison of the solution with burst test results and ASME B31G solutions.

关键词： submarine pipeline corrosion defects limit load

Numerical Study on Bank Effects for a Ship Sailing in Shallow Channel

在线全文

学校读者我要写书评

暂无评论

Journal of shanghai jiaotong university(Science) 2011年第1期16卷 91-96页

作者：姚建喜邹早建王化明 school of naval architecture Ocean and Civil EngineeringShanghai Jiaotong University school of naval architecture Civil engineering Zhejiang Ocean University

A numerical study on bank effects in shallow channels is carried out by using a first-order Rankine source panel method.A container ship sailing along a vertical bank and a sloping bank at different forward speeds,different water depths and different distances between the bank and the ship hull is taken as *** sway force and yaw moment acting on the hull are calculated and the influences of the speed,water depth and distance between the bank and ship hull on the hydrodynamic force and moment are *** study can provide insight into the bank effects,as well as to give guidance on ship manoeuvring and control in restricted waterways,which is helpful to the navigation safety.

关键词： bank effects shallow water hydrodynamic forces panel method

On the 8th-order Drag Coefficient Formula of a Sphere in a Uniform Stream: a Simplified Discription

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1998年第4期3卷 256-260页

作者： Shjun LIAO (school of naval architecture & ocean engineeringshanghai Jiao Tong university,shanghai 200030, China)E-mail: sjliao@*** school of naval architecture & ocean engineering shanghai jiaotong university Shanghai 200030 China

We verify from both physical and mathematical view-points that the viscons drag coefficient formulas of a sphere in a uniform stream should be an odd function of Reynolds number. Therefore, the famous Oseen’s (1910) drag coefficient formula CD for a sphere would seem to be wrong even qualitatively. Besides,we propose up-to 8th-order drag coefficient formulas by means of the homotopy analysis method, a new analytic technique developed by the author. Moreover, all of our up-to8th-Order drag coefficient formulas are odd functions of Reynolds nUmber and agree better with experimental data in a larger range of Reynolds number. So, our high-order drag coefficient formulas are better, not only qualitatively but also quantitatively, than those given by Oseen, Goldstein, Proudman and Pearson.

关键词： drag coefficient viscous flow past a sphere uniformly valid analytic approximation

NUMERICAL SIMULATION OF TIP-CLEARANCE FLOW IN CASCADE

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2003年第1期15卷 62-66页

作者： Chen Long, Yang Chen jun, Wang Guo qiangschool of naval architecture and ocean engineering, shanghai jiaotong university, shanghai 200030, China school of naval architecture and ocean engineering Shanghai Jiaotong University Shanghai 200030 China

The tip-clearance flow in a cascade was numerically simulated by solving theRANS equations of incompressible fluids. The computational model was based upon the artificialcompressibility formulation proposed by Chorin. The Baldwin-Lomax turbulence model was used to makethe governing equations closed. For the specific structure of tip-clearance flow, a multi-block gridstructure was adopted to facilitate numerical compulations. The comparison of numerical resultswith experimental data indicates that the present method is capable of simulating tip-clearanceflows with satisfactory accuracy.

关键词： cascade flow tip-clearance flow multi-block grid structure

基于实际预压载作业的自升式平台环境载荷图谱绘制新思路

在线全文

学校读者我要写书评

暂无评论

哈尔滨工程大学学报（英文版） 2024年第1期23卷 209-221页

作者：孙承猛林海花张志刚孙洪源周立师 naval architecture and Port engineering College Shandong Jiao Tong UniversityWeihai 264209China school of ocean engineering Harbin Institute of TechnologyWeihai 264209China China Merchants Jinling Shipyard(Weihai)Co. Ltd.Weihai 264207China

The environmental load chart is an important technical support required for the jack-up drilling platform to facilitate its adaptation to different operating waters and ensure the safety of *** chart is a crucial part of the platform operation *** chart data are closely related to external factors such as water depth,wind,wave,and current conditions of the working water,as well as to the structural characteristics of the platform itself and the number of variable *** study examines the platform state under extreme wind,wave,and current conditions during *** addition,this study focuses on the difference between the ultimate reaction force of the pile leg during preloading and the reaction force of the pile leg without considering any environmental load before ***,the relationship between the difference and the new reaction force of the pile leg caused by the combination of different environmental conditions is established to facilitate the construction of a new form of environmental load *** newly formed chart is flexible and simple;thus,it can be used to evaluate the environmental adaptability of the platform in the target well location and provides the preloading target demand or variable load limit according to the given environmental ***,the platform can perform personalized preloading operations,thereby improving its capability to cope with complex geological conditions,such as reducing punch-through *** condition reduces the load on jacking system devices and increases its service life.

关键词： Jack-up Environmental load chart Preloading Geometrically nonlinear effect Punch through

Numerical Prediction of Marine Propeller Noise in Non-Uniform Inflow

在线全文

学校读者我要写书评

暂无评论

China ocean engineering 2013年第1期27卷 33-42页

作者：潘雨村张怀新 State Key Laboratory of ocean engineering Shanghai JiaoTong University Department of naval architecture Naval University of Engineering

A numerical study on the acoustic radiation of a propeller interacting with non-uniform inflow has been conducted. Real geometry of a marine propeller DTMB 4118 is used in the calculation, and sliding mesh technique is adopted to deal with the rotational motion of the propeller. The performance of the DES （Detached Eddy Simulation） approach at capturing the unsteady forces and moments on the propeller is compared with experiment. Far-field sound radiation is predicted by the formation 1A developed by Farassat, an integral solution of FW-H （Ffowcs Williams-Hawkings） equation in time domain. The sound pressure and directivity patterns of the propeller operating in two specific velocity distributions are discussed.

关键词： hydroacoustics Detached Eddy Simulation (DES) Ffowcs Williams-Hawkings (FW-It) equation marine propeller non-uniform inflow