Groupiness of Sea Waves and Their Characteristic Parameters   总被引：1，自引：0，他引：1  

Yu Yuxiu Gui Manhai Professor  Dept. of Civil Eng. Dalian University of Technology  Dalian Master  Dept. of Civil Eng. Dalian University of Technology  Dalian 《中国海洋工程》1996,(1)

Three methods for studying wave groups and their main parameters for describing wave groupiness are reviewed in this paper. Then they are analyzed and compared combined with field data from both aspects of group height and group length. A method and two parameters that can describe wave groupiness are suggested. The groupiness parameters of sea waves at three field stations are given. The effects of groupiness on both distributions of the wave height and the phase of component waves are investigated. The effects of datum length on the calculated value of grouping parameters are also discussed.  相似文献   

The Lift Forces Acting on a Submarine Composite Pipeline in a Wave-Current Coexisting Field     

Li Yucheng  Zhang Ningchuan Professor  Dalian University of Technology  Dalian . Lecturere  Delian University of Technology  Dalian 《中国海洋工程》1994,(1)

- A composite pipeline is defined as a main big pipe composed of one or several small pipes. The flow behaviour around a submarine composite pipeline is more complicated than that around a single submarine pipeline. A series model test of composite pipelines in a wave-current coexisting field was conducted by the authors. Both in-line and lift forces were measured, and the resultant forces were also analyzed. The results of lift forces and resultant forces are reported in this paper. It is found that the lift force coefficients for composite pipelines are well related to the KC number. The lift force coefficients for an irregular wave-current coexisting field are smaller than those for a regular wave-current coexisting field. The frequency of lift force is usually twice the wave frequency or higher. The authors test indicates that the resultant forces are about 10 to 20 percent larger than in-line forces (horizontal forces). The effect of water depth is analyzed. Finally, the relationship between lift f  相似文献   

Finite Element Method for Design of Reinforced Concrete Offshore Platforms     

Song Yupu  Wang Jian Associate Professor  Dept. of Civil Engineering  Dalian University of Technology  Dalian Lecturer  Dept. of Civil Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1992,(1)

A design method of reinforced concrete (R. C.) offshore platforms with nonlinear finite element analysis is proposed. According to the method, a computer program is developed. In this program nonlinear constitutive relationships and strength criteria of concrete and steel bars are included, and the progressive cracking and crushing of the concrete are taken into account. Based on the stress distribution obtained by the nonlinear finite element analysis, the amount of reinforcement in the control sections can be computed and adjusted automatically by the program to satisfy the requirement of the design. The amount of reinforcement required in the control sections, which are obtained with the nonlinear finite element analysis, is agreeable to that obtained in the experiment. This shows that the design method of R. C. offshore platform with the nonlinear finite element method proposed by the authors is reliable for practical use.  相似文献   

Hydrodynamic Coefficients for Grouping Piles Under the Action of Irregular Waves   总被引：2，自引：0，他引：2  

Yu Yuxiu Shi Xianghong Professor 《中国海洋工程》1994,(2)

-The hydrodynamic coefficients for each of two piles and three piles in both side-by-side arrangement and tandem arrangement under the action of irregular waves are experimentally investigated. These coefficients vary with the KC number, the relative pile spacing, the number of piles and the pile location, and their relationships are presented in this paper. They can be used in Morison Equation and other equations to calculate directly the in-line wave forces and the transverse forces on each pile in array.  相似文献   

A Review of Studies on the Interaction Between Waves and Muddy Bottom     

Zhao Zidan Professor  Doctoral Supervisor  Tianjin University  Tianjin 《中国海洋工程》1992,(2)

This paper presents a brief review of the results on the interaction between waves and muddy bottom obtained during the last decade including the results obtained by the author at the Coastal Engineering Laboratory of Tianjin University.  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   

Modulus of Subgrade Reaction for Laterally Loaded Piles in Multiple Layered Foundation   总被引：1，自引：1，他引：1  

Lu Ziai Associate Professor  Dept. of Navigation  Ocean Engineering  Hohai University  Nanjing 《中国海洋工程》1997,(4)

-According to the field test data of laterally loaded steel piles at home and abroad,an empiri-cal formula for evaluating the modulus of subgrade reaction under static load in layered soil is proposed.The suggested formula takes account of not only non-linearity of K_s with the depth but also its variationwith the load.It is shown that the computed bending moments along the pile shaft and the deflection atthe pile top are consistent with the measured ones.  相似文献   

Cumulative Deformation of Soft Clay Under Cyclic Loading   总被引：2，自引：1，他引：2  

Yan Shuwang Yan Chi Zhang Jianguo Professor  Tianjin University  Tianjin Lecturer  Tianjin University  Tianjin 《中国海洋工程》1993,(3)

Reconstituted specimens are prepared by means of vacuum preloading. Both static and cyclic triaxial tests are carried out, with the specimens consolidated under different principal stress ratios. A finite element method is put forward for calculating the cumulative deformation of soft clay under cyclic loading.  相似文献   

Energy balance of the Arctic     

E. Vowinckel  Professor Dr. Svenn Orvig 《Theoretical and Applied Climatology》1965,13(4):480-502

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Die Geologische Vereinigung verlieh im Jahre 1962 die Gustav-Steinmann-Medaille     

Professor Dr. Eugene Raguin 《International Journal of Earth Sciences》1962,52(1):I-I

Ohne Zusammenfassung  相似文献