水下柔性鱼形机构原理及单尾鳍板水动力试验研究   总被引：4，自引：0，他引：4  

张向明  李玉江 《海洋工程》2002,20(1):84-90

柔性鱼形机构是模拟鱼类运动的一种仿生机械系统。对鱼类运动的观察与研究 ,实质上是寻求水域中最优推进形式的过程 ,是工程优化设计的途径之一。在研究及优化柔性鱼形机构时涉及到水动力学及控制模型的问题 ,因此取出鱼形机构的尾鳍部分进行敞水试验 ,既能为有关模型的建立提供依据 ,更重要的是对鱼形机构的可行性进行论证  相似文献   

New Method for Predicting the Motion Responses of A Flexible Joint Multi-Body Floating System to Irregular Waves   总被引：4，自引：0，他引：4  

CHEN  Xujun 《中国海洋工程》2001,(4):491-498

A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based solutions with experimental results has shown good agreement.  相似文献   

Nonlinear Behaviour of Coflexip Risers     

Kamal Zare  T. K. Datta 《中国海洋工程》2001,(4):479-490

A modified Newton-Raphson iterative technique is formulated for obtaining the static configuration of the Lazy "S" flexible marine riser between the floater and mid-arch buoy under its submerged self weight and the applied top tension. The geometrically non-linear problem is solved by finite difference with the above technique. The problem is formulated as a regular boundary value problem with specified moments and deflections at both ends. Usually the bending stiffness of the flexible riser made of Coflexip pipe is very low. By use of the above analysis, several flexible riser configurations are analyzed and their characteristic behaviors are investigated. Also, changes in the riser characteristics due to quasi-static motion of the floater end are estimated for the safety of the riser layout.  相似文献   

Discrete Element with Flexible Connector for Dynamic Analysis of 3-D Beam Structures   总被引：1，自引：1，他引：1  

Cheng Baorong  Zheng Zhaochang Hou Zhichao Professor 《中国海洋工程》1997,(1)

Combined multi-body dynamics with structural dynamics,a new discrete element with flexibleconnector,which is applicable for 3-D beam structures,is developed in this paper.Both the generalizedelastic coefficient matrix of the flexible connector and the mass matrix of discrete element may be off-diag-onal in a general case.The zero-length rigid element is introduced to simulate the node at which multiple el-ements are jointed together.It may also be effective when the axes of adjacent elements are not in the sameline.The examples for eigenvalue calculation show that the model is successful.It can be extended to thegeometric nonlinear response analysis.  相似文献   

Teaching Historical Geographies of American Film Production     

《The Journal of geography》2012,111(6):250-260

Abstract

The geographies of Hollywood are multiple, contradictory, ephemeral and tangible. Our preconceived conceptions of space and place play a dynamic role in what elements we tend to focus on when discussing the cultural industry of American cinema. This essay uses Hollywood as a metaphor for the American film production industry and a historical geography of production as a framework to explore major spatial and structural changes within this industry from its inception to the present. It highlights teaching methods and materials from the course A Geography of Film at Southern Connecticut State University. Mode of production relates to the economic process where capital, labor, knowledge and imagination are blended to produce a culturalized product for consumption. The American film industry is a fine example of the commodification of culture.  相似文献   

Large Deflection Dynamic Response Analysis of Flexible Hull Beams by the Multibody System Method     

ZHANG Xiaojun WU Guorong 《中国海洋大学学报(英文版)》2007,6(2):205-208

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褥垫层地复合地基受力模式的影响及工程实例分析     

梅传书  钟登华  徐海峰 《水文地质工程地质》2001,28(6):54-56

采用复合地基方案时，在基础和复合地基之间可设一层粒状材料垫层，以起“调整均化”作用。本文通过分析褥垫层对复合地基受力模式的影响，探讨了褥垫层在保证桩土共同承担荷载，改善复合地基承载性状等方面所具有的重要意义。最后通过对某具体工程实例的分析，得出一些相关结论。  相似文献   

对西康铁路软岩和极软岩隧道支护的认识     

郑伟 《水文地质工程地质》2001,28(4):40-42

西康铁路沿线软质岩带在秦岭以南分布较广。在软质岩带集中出露的地段，地质情况复杂。隧道围岩稳定性差，其工程地质特性随着岩层矿物成分、产状、风化程度、地下水赋存特征的不同有很大差异。本文介绍了西康铁路南段软岩和极软岩带的设计指导思想，并结合西康线具体情况，具体分析了软岩极软岩对隧道施工的影响，对该类型地层铁路隧道的设计、施工，提出几点建议，作为今后工作的借鉴。  相似文献   

Gray box identification of flexible structures: application to robust active vibration suppression control     

A. Forrai  S. Hashimoto  A. Isojima  H. Funato  K. Kamiyama 《地震工程与结构动力学》2001,30(8):1203-1220

The paper deals with gray box identification of flexible structures and active vibration suppression from a robust control perspective. First, the linearized mathematical model of an N‐storey flexible structure is presented. Next, the generalized mathematical model is particularized for the investigated three‐storey flexible structure. The considered flexible structure is identified based on black box and gray box identification methods and the model's parametric uncertainties are deduced. Furthermore, control constraints are presented for the design problem, in case of velocity as well as acceleration feedback, from a robust control perspective. Finally, the effectiveness of the control system is tested through experiments, when the input disturbance is assumed to be a sinusoidal one as well as a historical earthquake record (1940 El Centro record). Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

论柔性生产与产业集聚   总被引：12，自引：2，他引：12  

朱华晟  王缉慈 《世界地理研究》2001,10(4):39-46

20世纪中后期，随着新技术革命加速推进和市场竞争日益激烈，很多产品的生命周期不断缩短，消费需求日趋多样化和复杂化。在这样的环境下，工业生产方式也发生了相应的变化，即从福特制向后福建特制转变。同时，在传统老工业区外围出现了以柔性生产为特征的大量企业集聚体，它们彼此之间通过分工与协作而结成稠密的区域网络组织，以共同面对快速变化的外部市场环境和技术条件。这种新型的集聚现象与柔性生产之间是否存在着内在的联系呢？理论界对此一直有争议。作者认为，柔性生产具有促进产业集聚的动力机制，并运用交易成本和知识创新的有关理论，以及日本丰田公司的及时生产系统为例进行论证，最后提出进一步研究的方向。  相似文献