Huang Y.,Shanghai JiaoTong University |
Jiang Z.,Shanghai JiaoTong University |
He C.,Shanghai Waigaoqiao Shipbuilding Company |
Song B.,Shanghai JiaoTong University |
Liu L.,Shanghai JiaoTong University
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture | Year: 2016
In the process of product design, it is usually difficult for engineers to find and reuse others' lesson-learned knowledge, which is usually not well collected by an enterprise. This study proposes a model of an inner-enterprise wiki system integrated with a semantic search framework to support the accumulation and reuse of lesson-learned knowledge in product design. The accumulated wiki web pages in inner-enterprise wiki system can be viewed as a large lesson-learned knowledge repository, which stores engineers' wisdom of product design and is the basis of semantic search for knowledge reuse. The semantic-based knowledge search mechanism of inner-enterprise wiki system is presented, which can overcome limitations of traditional keyword-based search in existing wiki systems. To validate our approach, an innerenterprise wiki system implementation is introduced and some experiments are done. Effectiveness of semantic search mechanism in inner-enterprise wiki system is verified from several viewpoints such as comparison of precision and recall between proposed method and a keyword-based one. The performance of utilizing inner-enterprise wiki system for knowledge reuse is evaluated and the results show that inner-enterprise wiki system can improve the performance of learning. The promising results confirm the feasibility of our approach in helping engineers to better reuse needed lesson-learned knowledge. © IMechE 2014.
Sun S.-L.,Shanghai JiaoTong University |
Hu J.,Harbin Engineering University |
Hu J.-Z.,Shanghai Waigaoqiao Shipbuilding Company
Chuan Bo Li Xue/Journal of Ship Mechanics | Year: 2013
A doubly asymptotic approximation for the governing wave equation was adopted to study the initial impact problem of a compressible water column on an elastic plate. The governing equation is solved by a boundary element method and non-linear boundary conditions are used to update the unknown free surface. Numerical results are compared with analytic solutions by Korobkin (2008) under the same linear boundary conditions, to study the influence of the doubly asymptotic approximation on the numerical results and testify its accuracy, which shows that good agreements are found. The influence of the non-linear boundary conditions on the displacements and the pressure of the plate center is analyzed and discussed.
Li C.,Harbin Engineering University |
Ren H.,Harbin Engineering University |
Xu D.,Harbin University of Science and Technology |
Ji Z.,Shanghai Waigaoqiao Shipbuilding Co.
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE | Year: 2014
The objective of this paper is to develop a design method of small-scale distortion model for ultimate bearing capacity test. The ultimate moment is an important index of ship girder strength. Experimental analyses are regarded as the most straightforward and effective methods to predict ultimate moment of hull girder, especially full-scale and/or large-scale model testing. However, large-scale model test not only requires high loading capacity of test device, but it also costs a lot of human and material resources. Based on the similarity theory and failure mechanism of hull girder under bending, a small-scale distortion model design method is presented in this paper. In which, the transverse section is divided into several parts, such as main deck, middle deck, bottom and so on. Then, two similar criterions are required to follow. There are section modulus of each part and critical stress of main stiffened plats. The similar section modulus ensures a similar stress distribution of transverse section between model and real structures under bending; the similar critical stress ensures the same failure modes of stiffened plates. Based on this method, a real vessel is taken as example to design its small-scale (1/25 scale) distortion model. The simulating results indicate that this model design method is precise and reliable. Copyright © 2014 by ASME.
Tao N.-R.,Shanghai JiaoTong University |
Jiang Z.-H.,Shanghai JiaoTong University |
Liu J.-F.,Shanghai Waigaoqiao Shipbuilding Co.
Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS | Year: 2010
Spatial scheduling problem as key resource scheduling problem was studied. Differences between spatial scheduling problem and three-Dimensional Bin Packing Problem (3D-BPP) were compared. Based on 3D spatial scheduling with time window as constraint, an improved heuristic positioning rules based on Extreme Points (EP) was proposed. Optimization algorithm based on tabu search and EP-based positioning rules was presented. Finally, a simulation experiment was provided to illustrate the effectiveness of the proposed approach.
Yang Y.,Shanghai Waigaoqiao Shipbuilding Co. |
Huang S.,Harbin Engineering University
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2016
Based on research of existing methods for calculating mooring line damping, in this paper, we introduce an improved quasi-static method. First, we calculate the mooring line damping for several series of load cases using the Huse quasi-static method, Liu quasi-static method, and the fully dynamic finite element method. Then, in the calculation of the two quasi-static methods, we take into account the horizontal displacement of the mooring line element, and again calculate the mooring line damping, since it is significant in the fairlead position. Finally, we analyze the results and compare them to better understand the features and disadvantages of the various methods. After verification, we introduce a improved quasi-static method. This new method demonstrates acceptable accuracy and reliability. The results obtained are similar to those generated by the finite element method. This method can be regarded as an effective auxiliary means for calculating mooring line damping. © 2016, Editorial Department of Journal of HEU. All right reserved.
Zhou J.,Shanghai Maritime University |
Xu L.,Shanghai Maritime University |
Hu Y.,Shanghai Maritime University |
Zhu K.,Shanghai Waigaoqiao Shipbuilding Co.
ICCET 2010 - 2010 International Conference on Computer Engineering and Technology, Proceedings | Year: 2010
To simulate human action in virtual environment of marine engine room, Software Creator and Vega of Multigen-Paradigm, and DI-Guy virtual human module of Boston Dynamics Inc. are introduced to construct the virtual human operation in Virtual Roaming System of marine engine room, body model in DI-Guy is modified, the action model on the hand part is intensified and collision detection of virtual human in real-time movement is studied. Thus real-time operations of virtual marine engineers in virtual engine room environment are realized, including operations of central control console in central control room, assembly, disassembly and maintenance of equipment parts, etc. The result indicates that this method can better simulate the engine room environment, help trained marine engineers knowing more about equipment layout and operations in the engine room, and improve the effectiveness of seafarers training. © 2010 IEEE.
Liang X.,Shanghai JiaoTong University |
Liang X.,Shanghai Waigaoqiao Shipbuilding Co. |
Yang J.,Shanghai JiaoTong University |
Li J.,Shanghai JiaoTong University |
Li X.,Shanghai JiaoTong University
Ocean Engineering | Year: 2011
In actual sea states, damage to offshore floating structures is usually caused by a few extreme waves or wave groups in an irregular wave train. Accurate simulation of the irregular wave trains can lay a solid foundation for understanding the local flow field and impact loads that would potentially cause such damage. This paper describes how the generation of a single extreme wave was investigated. Determination of the wave-maker motion for generating specified irregular wave trains is the key to this work. First, an experimental irregular wave train was decomposed into a certain number of small-amplitude waves. Fourier series expansion was performed to determine the amplitude and the initial phase angle of each wave component. Then a hydrodynamic transfer function was used to calculate the amplitude of the wave-maker motion associated with each wave component. Superposition was made on all the wave components to get the final wave-maker motion. During the numerical simulation, calculated horizontal velocity profiles of the extreme wave at different moments were analyzed and compared with experimental results, and a satisfactory agreement was obtained. In the simulation, VOF method was employed to capture the free surface, and a dissipation zone was used to deal with wave reflection. © 2010 Elsevier Ltd.
Du J.-Q.,Shanghai JiaoTong University |
Du S.-J.,Shanghai JiaoTong University |
Zhao D.-L.,Shanghai Waigaoqiao Shipbuilding Co. |
Tang W.-Y.,Shanghai JiaoTong University
Yantu Lixue/Rock and Soil Mechanics | Year: 2013
Besides the interaction of the multiple stress superposition from piles shaft friction, pile bottom resistance and contact stress between low caps and soil, the clamping action makes the cap-pile-soil interaction more complicated in pile foundation with large pile diameter and small spacing. 3D finite difference program is employed to evaluate the pile-soil-cap interaction with the change of vertical load, while the pile spacing and pile diameter remain constant in the analysis procedure. Analysis is carried out to explain the interaction of cap-pile-soil from the following aspects such as the lateral friction of soil in each layer, load on the top of characteristic piles, load-settlement relationship, vertical displacement of soil between piles, etc. The results show that: the clamping action on the upper soil among piles will decrease, and the pile shaft friction in the upper part will increase when the load exceeds 117.8 MN which is slightly larger than Pu/2 (Pu means ultimate bearing capacity of piles group); the lower part of pile shaft friction shows a trend of decrease due to the influence of the multiple stress superposition, and the decrease trend in characteristic piles has different influence scope; the load, which makes settlement of piles group achieve 5% of pile diameter, can be regarded as the vertical ultimate bearing capacity of piles group, and it is reasonable; when the ratio of piles group's settlement to pile diameter exceeds 1%, the proportion of the load carried by piles decreases because of the cap contribution.
Zhang Y.-F.,Hohai University |
Wang S.-S.,Hohai University |
Gan S.-L.,Shanghai Waigaoqiao Shipbuilding Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2016
A beam's damage detection method based on coherence function of its random vibration was presented here. It was based on the principle that the nonlinearity of a structure's dynamic responses increases after its local structure suffering a loss of stiffness due to damage. Furthermore, a modified local damage factor (MLDF) method was proposed. This method was capable of determining the presence, severity, and location of structural damage at the same time. By including the dynamic characteristics of the intact local structure in this method, the influences of structural nonlinearity, imperfections, and system noise were considered, so the accuracy of damage detection was improved. As a demonstration, the tests of a cantilever beam with different magnitudes of local damages were conducted to validate the proposed method. The experimental results indicated that the method can be used to detect single-crack and multi-crack of the cantilever beam accurately and reliably. © 2016, Editorial Office of Journal of Vibration and Shock. All right reserved.
Yu J.,Shanghai JiaoTong University |
Cai H.,Shanghai JiaoTong University |
Bu F.,Shanghai JiaoTong University |
Liu A.,Shanghai JiaoTong University |
Liu A.,Shanghai Waigaoqiao Shipbuilding Corporation
Journal of Multimedia | Year: 2012
This paper proposes an OWL-S framework for distributed CAD system based on the combination of semantic web service and CAD technology. Service ontology mapping mechanism is analyzed in detail and semantic model is built with the study of the correlation across the geometry modeling service. On the purpose of accommodating the design pattern of network modeling, this framework supports the service composition of three- dimensional geometry modeling and achieves further integration of service information. At last, a case study from the developed prototype system shows the feasibility and flexibility of this method under distributed CAD environment. © 2012 Academy Publisher.