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Effect of configuration on magnetic field in cold crucible using for continuous melting and directional solidification 被引量:4
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作者 陈瑞润 杨劼人 +4 位作者 丁宏升 黄锋 苏彦庆 郭景杰 傅恒志 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第2期404-410,共7页
To improve the power efficiency and optimize the configuration of cold crucible using for continuous melting and directional solidification (DS), based on experimental verification, 3D finite element (FE) models w... To improve the power efficiency and optimize the configuration of cold crucible using for continuous melting and directional solidification (DS), based on experimental verification, 3D finite element (FE) models with various configuration-elements were developed to investigate the magnetic field in cold crucible. Magnetic flux density (B) was measured and calculated under different configuration parameters. These parameters include the inner diameter (D2), the slit width (d), the thickness of crucible wall, the section shape of the slit and the shield ring. The results show that the magnetic flux density in z direction (Bz) both at the slit and at the midpoint of segment will increase with the decrease of D2 or with the increase of the width of the slit and the section area of wedge slit or removing the shield ring. In addition, there is a worst wall thickness that can induce the minimum Bz for a cold crucible with a certain outer diameter. 展开更多
关键词 cold crucible magnetic flux density configuration design directional solidification
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Electromagnetic simulation and experimental analysis of microwave heaters for asphalt pavements 被引量:3
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作者 朱松青 张志胜 史泰龙 《Journal of Southeast University(English Edition)》 EI CAS 2011年第4期410-416,共7页
In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and app... In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and applied to the structural design of a microwave heater. The structural sizes of the incentive cavities are determined based on the waveguide transmission line theory. Using IE3D software, electromagnetic simulations are respectively carried out in four different situations, including the distances between the magnetron probes (antennas) and a short-circuit board, different horn electric lengths and aperture sizes, different dielectric properties of the asphalt mixture, and the distances between the asphalt surface and the mouth cavity. The results show that, when the distance between the magnetron probe and the short-circuit board is 32.5 ram, it is the best installation site; reduction of aerial length is the main factor in improving the heating uniformity. When the aggregate is limestone, the best heating effect can be produced. Maximum radiation efficiency can be realized by adjusting the space between the heater radiation port and the asphalt pavement. The experimental results of asphalt mixture heating in four different situations have a substantial agreement with the simulation results, which confirms that the developed microwave heater can achieve better impedance matching, thus improving the quality and efficiency of heating regeneration. 展开更多
关键词 microwave heater excitation cavity structural design electromagnetic simulation temperature distribution experimental analysis
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Durability zonation standard of concrete structure design 被引量:5
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作者 金伟良 吕清芳 《Journal of Southeast University(English Edition)》 EI CAS 2007年第1期98-104,共7页
Durability zonation standard (DZS) is proposed to provide useful parameters for durable concrete structure design. It deals not only with the influence of environment on structures, but also with types, functions an... Durability zonation standard (DZS) is proposed to provide useful parameters for durable concrete structure design. It deals not only with the influence of environment on structures, but also with types, functions and importance of structures based on the theory of life cycle cost(LCC). First, the basic concept of DZS for concrete structure design is defined. Then the basic principles for DZS are established. The factors for zonation according to natural environmental conditions and structural importance are identified. The usefulness of DZS by citing a real application for concrete highway bridges in Zhejiang Province is demonstrated. Finally, durability regulations are provided accordingly to zonation. 展开更多
关键词 durability zonation standard concrete structure design zonation map life cycle cost
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Structural design and experimental research of microwave radiation heater for asphalt pavements 被引量:2
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作者 朱松青 史金飞 《Journal of Southeast University(English Edition)》 EI CAS 2009年第1期68-73,共6页
In order to improve the efficiency of heating and the uniformity of temperature distribution in recycling asphalt mixtures, a pyramidal radiation heater is designed. The principles of designing horn surface size and a... In order to improve the efficiency of heating and the uniformity of temperature distribution in recycling asphalt mixtures, a pyramidal radiation heater is designed. The principles of designing horn surface size and antenna length are established according to the law of energy conservation and microwave antenna radiation theory. Modeling and simulation are carried out using IE3D software. The simulation results demonstrate that, with a fixed horn surface size, the shortened electric antenna length is the main factor leading to the improved heating uniformity. On the other hand, with a fixed antenna length and diminished surface size, the standing wave ratio decreases with the improved radiation efficiency. Furthermore, the efficiency of radiation drops with increased distance between the horn surface and the asphalt pavement. Microwave heating experiments are carried out using this type of heater. The temperature distribution of asphalt samples is obtained by the grid temperature measurement method, and Matlab simulation is performed. The experimental results are in good agreement with the simulation. 展开更多
关键词 asphalt mixtures microwave heating temperature distribution microwave radiation heater structural design
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APPROXIMATION TECHNIQUES FOR APPLICATION OF GENETIC ALGORITHMS TO STRUCTURAL OPTIMIZATION 被引量:1
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作者 金海波 丁运亮 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第2期147-154,共8页
Although the genetic algorithm (GA) has very powerful robustness and fitness, it needs a large size of population and a large number of iterations to reach the optimum result. Especially when GA is used in complex str... Although the genetic algorithm (GA) has very powerful robustness and fitness, it needs a large size of population and a large number of iterations to reach the optimum result. Especially when GA is used in complex structural optimization problems, if the structural reanalysis technique is not adopted, the more the number of finite element analysis (FEA) is, the more the consuming time is. In the conventional structural optimization the number of FEA can be reduced by the structural reanalysis technique based on the approximation techniques and sensitivity analysis. With these techniques, this paper provides a new approximation model-segment approximation model, adopted for the GA application. This segment approximation model can decrease the number of FEA and increase the convergence rate of GA. So it can apparently decrease the computation time of GA. Two examples demonstrate the availability of the new segment approximation model. 展开更多
关键词 approximation techniques segment approximation model genetic algorithms structural optimization sensitivity analysis
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New Architecture of Pipeline CORDIC 被引量:1
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作者 李滔 韩月秋 《Journal of Beijing Institute of Technology》 EI CAS 1999年第1期89-94,共6页
Aim To design an ASIC based on CORDIC(coordinate rotations digital computer) to meet the requirement of coordinate conversion in high speed radar signal processing. Methods A new pipeline CORDIC architecture easi... Aim To design an ASIC based on CORDIC(coordinate rotations digital computer) to meet the requirement of coordinate conversion in high speed radar signal processing. Methods A new pipeline CORDIC architecture easily realized in VLSI was introduced. Results and Conclusion The results of hardware simulation with FPGA show that the pipeline CORDIC architecture meets the requirement. 展开更多
关键词 CORDIC pipeline architecture ASIC design
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Integrated Assembly Structure Design Within Concurrent Engineering
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作者 常向青 宁汝新 +2 位作者 姚珺 张旭 唐承统 《Journal of Beijing Institute of Technology》 EI CAS 2001年第3期306-311,共6页
Taking a microwave product as an example, a system of integrated assembly structure design is presented. Getting design constraints from the upstream design section through product data management(PDM), the system gen... Taking a microwave product as an example, a system of integrated assembly structure design is presented. Getting design constraints from the upstream design section through product data management(PDM), the system generates the assembly scheme using the case? based method, then assigns the design requirements into each component of the assembly. The detail design for each component can be performed under these design constraints. In order to practise concurrent design, the system sends the final design result to the upstream section and downstream section through PDM to achieve information sharing and integration. 展开更多
关键词 concurrent engineering assembly structure design case-based reasoning design constraints
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Spatial structural analysis of main saddle for single tower spatial cable self-anchored suspension bridge
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作者 李建慧 李爱群 +1 位作者 袁辉辉 李喜平 《Journal of Southeast University(English Edition)》 EI CAS 2009年第3期372-375,共4页
Based on the engineering background of the Jiangxinzhou Bridge in Nanjing, issues related to the spatial main saddle of the self-anchored suspension bridge are studied. The refinement finite element model is establish... Based on the engineering background of the Jiangxinzhou Bridge in Nanjing, issues related to the spatial main saddle of the self-anchored suspension bridge are studied. The refinement finite element model is established by the secondary development technology based on the platform of the general finite element program, and a reasonable load pattern is used in its spatial structural analysis, by which its path of force transference and stress distribution are obtained. Matched with the spatial main cable, the tangency point correction method is also discussed. The results show that the lateral wall stress of the saddle groove is higher than the stress within the wall due to the role of lateral forces in the finished bridge state; the horizontal volume force of the main cable can generate a gradient distributed vertical extrusion pressure on the saddle clamping device and the main saddle body; the geometric nonlinear effect of the self- anchored suspension bridge cable system in the construction process is significant, which can be reflected in the spatial tangent point position of the main cable with the main saddle changes a lot from free cable to finished cable. 展开更多
关键词 self-anchored suspension bridge finite element main saddle spatial cable structural design
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Design of a novel modular self-reconfigurable robot capable of self-turning
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作者 乔贵方 宋光明 +2 位作者 张颖 孙慧玉 韦中 《Journal of Southeast University(English Edition)》 EI CAS 2016年第3期293-300,共8页
To solve the problem of inaccurate angle adjustment in the self-assembly process, a new homogenous hybrid modular self-reconfigurable robot-Xmobot is designed. Each module has four rotary joints and a self-turning mec... To solve the problem of inaccurate angle adjustment in the self-assembly process, a new homogenous hybrid modular self-reconfigurable robot-Xmobot is designed. Each module has four rotary joints and a self-turning mechanism. With the proposed self-turning mechanism, the angle adjusting accuracy of the module is increased to 2°, and the relative position adjusting efficiency of the module in the self-assembly process is also improved. The measured maximum moving distance of the proposed module in a gait cycle is 11.0 cm. Aiming at the multiple degree of freedom (MDOF) feature of the proposed module, a motion controller based on the central pattern generator (CPG) is proposed. The control of five joints of the module only requires two CPG oscillators. The CPG-based motion controller has three basic output modes, i. e. the oscillation, the rotation, and the fixed modes. The serpentine and the wheeled movements of the H-shaped robot are simulated, respectively. The results show that the average velocities of the two movements are 15. 2 and 20. 1 m/min, respectively. The proposed CPG-based motion controller is evaluated to be effective. 展开更多
关键词 central pattern generator modular self-reconfigurable robot structural design motion simulation
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Motion simulation and experiment of a novel modular self-reconfigurable robot
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作者 吴秋轩 曹广益 费燕琼 《Journal of Southeast University(English Edition)》 EI CAS 2006年第2期185-190,共6页
Based on the character of the modular self-reconfigurable (MSR) robot, a novel homogeneous and lattice MSR robot, M-Cubes, was designed. Each module unit of the robot has 12 freedoms and is composed of six rotary jo... Based on the character of the modular self-reconfigurable (MSR) robot, a novel homogeneous and lattice MSR robot, M-Cubes, was designed. Each module unit of the robot has 12 freedoms and is composed of six rotary joints and one cubic link. An attached/detached mechanism was designed on the rotary joints. A novel space transmitting system was placed on the inner portion of the cubic link. A motor separately transmitted torque to the six joints which were distributed equally on six surfaces of the cubic link. The example of a basic motion for the module was demonstrated. The result shows that the robot is concise and compact in structure, highly efficient in transmission, credible in connecting, and simple in controlling. At the same time, a simulator is developed to graphically design the system configuration, the reconfiguration process and the motion of cluster modules. The character of local action for the cellular automata (CA) is utilized. Each module is simplified as a cell. The transition rules of the CA are developed to combine with the genetic algorithm (GA) and applied to each module to accomplish distributed control. Simulation proves that the method is effective and feasible. 展开更多
关键词 modular self-reconfigurable robot structure design motion simulation distributed control
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Structural Carpentry in Qing Dynasty-A Framework for the Hierarchically Modularized Chinese Timber Structural Design 被引量:1
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作者 龚清宇 《Transactions of Tianjin University》 EI CAS 2002年第1期16-21,共6页
This article, by using mathematical expressions, offers a scientific framework for understanding how the grading system of Qing′s structural carpentry determines the design and construction in the grand style timber... This article, by using mathematical expressions, offers a scientific framework for understanding how the grading system of Qing′s structural carpentry determines the design and construction in the grand style timber architecture.The Qing′s grand style timber structure, which is ready for prefabrication and assembly, is extremely hierarchical oriented and significantly standardized. The general procedure in designing a grand style timber structure is to start with the grade that defines the basic module (dou kou); next comes with the number of bracket set (cuan), the number of longitudinal bays and the number of purlins which affect its plan and cross section; thirdly choose a roof type that determines its longitudinal section and the facade as well. A series of formulae are conducted to help depict the layout, cross sectional roof curvature and special longitudinal treatments in 4 sloped and 9 spined roofs respectively. 展开更多
关键词 structural carpentry mathematical expression grand style Qing Dynasty modular system Chinese timber structural design
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Structure Design Considerations of a Sub-50nm Self-Aligned Double-Gate MOSFET
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作者 殷华湘 徐秋霞 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第12期1267-1274,共8页
A comprehensive way to design a sub 50nm SADG MOSFET with the ability of being fabricated by improved CMOS technique is described.Under this way,the gate length and thickness of Si island of DG device show many diffe... A comprehensive way to design a sub 50nm SADG MOSFET with the ability of being fabricated by improved CMOS technique is described.Under this way,the gate length and thickness of Si island of DG device show many different scaling limits for various elements.Meanwhile,the spacer insulator shows a kind of width thickness on device drain current and circuit speed.A model about that effect is developed and offers design consideration for future.A new design of channel doping profile,called SCD,is also discussed here in detail.The DG device with SCD can achieve a good balance between the volume inversion operation mode and the control of V th .Finally,a guideline to make a SADG MOSFET is presented. 展开更多
关键词 double gate MOSFET structure design sidewall effect SCD
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A working model of the Internet-based steel construction consulting system for architects
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作者 周琦 《Journal of Southeast University(English Edition)》 EI CAS 2003年第4期336-342,共7页
As Internet becomes largely used in the AEC (architecture, engineering andconstruction) industry, the main focus is in the area of information and project management. In thedynamic engineering consulting, less has bee... As Internet becomes largely used in the AEC (architecture, engineering andconstruction) industry, the main focus is in the area of information and project management. In thedynamic engineering consulting, less has been done so far. This research tries to find thepossibility and potential of the Internet application in design and consulting for the AEC industryby proposing a working model in specific area, steel construction. Several issues have beendiscussed: defining and formatting the typical procedure and character of the steel constructionconsulting, behavior approach based on activities among partners, and the model organization. 展开更多
关键词 steel construction consulting behavior approach object-oriented methods
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Challenges to Data-Path Physical Design Inside SOC 被引量:2
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作者 经彤 洪先龙 +5 位作者 蔡懿慈 许静宇 杨长旗 张轶谦 周强 吴为民 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第8期785-793,共9页
Previously,a single data-path stack was adequate for data-path chips,and the complexity and size of the data-path was comparatively small.As current data-path chips,such as system-on-a-chip (SOC),become more complex,m... Previously,a single data-path stack was adequate for data-path chips,and the complexity and size of the data-path was comparatively small.As current data-path chips,such as system-on-a-chip (SOC),become more complex,multiple data-path stacks are required to implement the entire data-path.As more data-path stacks are integrated into SOC,data-path is becoming a critical part of the whole giga-scale integrated circuits (GSI) design.The traditional physical design methodology can not satisfy the data-path performance requirements,because it can not accommodate the data-path bit-sliced structure and the strict performance (such as timing,coupling,and crosstalk) constraints.Challenges in the data-path physical design are addressed.The fundamental problems and key technologies in data-path physical design are analysed.The corresponding researches and solutions in this research field are also discussed. 展开更多
关键词 physical design data-path bit-sliced structure SYSTEM-ON-A-CHIP giga-scale integrated circuits very-deep-submicron
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Molecular Design and Electronic Structure Investigation of Novel Nitrogen Heteroatom 2-β-Naphthylbenzoxazoles
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作者 孙京国 冯玉玲 姚国伟 《Journal of Beijing Institute of Technology》 EI CAS 2002年第3期280-284,共5页
For the aim of finding new available functional materials, a series of nitrogen heteroatom 2 β naphthylbenzoxazole molecules were designed based on the experiment and theoretical studies of 2 β naphthylb... For the aim of finding new available functional materials, a series of nitrogen heteroatom 2 β naphthylbenzoxazole molecules were designed based on the experiment and theoretical studies of 2 β naphthylbenzoxazole molecule. Geometry optimization of the 2 β naphthylbenzoxazole was carried out by using Hyperchem Molecular Mechanics plus MM+. The planar molecular structure was obtained. The quantum chemistry calculating method PPP SCF CI, which is specially available to treat electron spectrum, was applied to investigate each novel designed molecules. Their electronic structures were analyzed in detail, it shows that total π electron energy decreased linearly with the number of replaced nitrogen. Single nitrogen atom located in benzoxazole ring or naphthalene ring results in contrary changes of level difference of FMO; multiple nitrogen atoms located in different molecular positions will lead to polarization of extremum in the level difference of FMO; and 5 nitrogen heteroatoms reach the culmination. Considering other electronic structure information, some favorable designed molecules were identified. 展开更多
关键词 naphthylbenzoxazole molecular design MM+ PPP SCF CI electronic structure
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各种船舶
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《交通建设与管理》 1996年第4期37-39,共3页
关键词 船体结构设计 巨型油船 结构·设计 多用途船 长江客船 车客渡船 船舶工程 滚装船 全球海上遇险和安全系统 结构形式
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Design and Study of a High Security ATM System
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作者 范瑞霞 赵则祥 张俊 《Journal of Beijing Institute of Technology》 EI CAS 2002年第1期41-44,共4页
Based on the characteristics of ATM system and the special requirement of financial transaction, an overall design of hardware and software structure of ATM was made. For software structure, the pattern of modules and... Based on the characteristics of ATM system and the special requirement of financial transaction, an overall design of hardware and software structure of ATM was made. For software structure, the pattern of modules and table? drive is adopted to realize the security of financial transaction and the diagnosis of communication fault. A new method, which is based on the application layer, transport layer and network layer, is used for diagnosing communication fault. Supporting both magnetic card and IC card, the system has been put into use in real financial systems, and has brought about both economic and social effects. 展开更多
关键词 ATM IC card SECURITY fault diagnosis
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Logical-Structure Modeling for Conceptual Design
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作者 孙正兴 张福炎 《Journal of Southeast University(English Edition)》 EI CAS 2001年第1期59-65,共7页
Based on the definition of a logic structure feature to relate logically functional requirements to geometric representation independent upon detailed geometric representation, this paper presents an idea of logical s... Based on the definition of a logic structure feature to relate logically functional requirements to geometric representation independent upon detailed geometric representation, this paper presents an idea of logical structure modeling for computer aided conceptual design and makes attempt to establish a representation formalism of logic structure modeling. The definition and representation of logical structure feature are given and an assembly module definition for supporting top down conceptual design is also proposed. The proposed scheme contributes to several aspects of conceptual design research, especially to provide elementarily a formal methodology for computer aided conceptual design system development and operation. 展开更多
关键词 conceptual design function form transformation logic structure feature representation formalism
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DESIGN OF WAVE-SHAPED SPACE TRUSS CONSIDERING THE EFFECT OF SUBSTRUCTURE
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作者 尹越 纪刚 +2 位作者 韩庆华 程万海 刘锡良 《Transactions of Tianjin University》 EI CAS 2001年第1期44-47,共4页
The wave-shaped space truss is used as the roof of the natatorium in Tianjin University,which ingeniously displays the function of the building.In this paper,the wave-shaped space truss is analyzed and designed,consid... The wave-shaped space truss is used as the roof of the natatorium in Tianjin University,which ingeniously displays the function of the building.In this paper,the wave-shaped space truss is analyzed and designed,considering the substructure made of reinforced concrete rigid frame and the space truss working together.Also,the anti-seismic characteristic of the wave-shaped space truss is studied based on the integral model. 展开更多
关键词 wave-shaped space truss effect of substructure anti-seismic design
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Optimal Structural Design of the Midship of a VLCC Based on the Strategy Integrating SVM and GA 被引量:11
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作者 Li Sun (1) welqi1986@gmail.com Deyu Wang (1) 《Journal of Marine Science and Application》 2012年第1期59-67,共9页
In this paper a hybrid process of modeling and optimization, which integrates a support vector machine (SVM) and genetic algorithm (GA), was introduced to reduce the high time cost in structural optimization of sh... In this paper a hybrid process of modeling and optimization, which integrates a support vector machine (SVM) and genetic algorithm (GA), was introduced to reduce the high time cost in structural optimization of ships. SVM, which is rooted in statistical learning theory and an approximate implementation of the method of structural risk minimization, can provide a good generalization performance in metamodeling the input-output relationship of real problems and consequently cuts down on high time cost in the analysis of real problems, such as FEM analysis. The GA, as a powerful optimization technique, possesses remarkable advantages for the problems that can hardly be optimized with common gradient-based optimization methods, which makes it suitable for optimizing models built by SVM. Based on the SVM-GA strategy, optimization of structural scantlings in the midship of a very large crude carrier (VLCC) ship was carried out according to the direct strength assessment method in common structural rules (CSR), which eventually demonstrates the high efficiency of SVM-GA in optimizing the ship structural scantlings under heavy computational complexity. The time cost of this optimization with SVM-GA has been sharply reduced, many more loops have been processed within a small amount of time and the design has been improved remarkably. 展开更多
关键词 very large crude carrier (VLCC) structural scantlings structural optimization METAMODEL supportvector machine (SVM) genetic algorithms (GA) double-hull oil tanker common structural rules (CSR)
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