Shear Failure of a Clamped Dented Tubular Beam Under Lateral Impact   总被引：1，自引：0，他引：1  

Wang Deyu  Zhang Shanyuan Associate Prof.  Depart  of Naval Archi.  Ocean Engineering  Shanghai Jiaotong University  Shanghai Prof.  Research Institute of Applied Mechanics  Taiyuan University of Technology  Taiyuan 《中国海洋工程》1996,(2)

- The shear failure of a rigid-plastic dented clamped tubular beam under the lateral impact of a mass is investigated. Both the denting and the impact point are in the middle span of the beam. It is assumed that denting does not spread during the shear sliding. Numerical results show that the axial force and lateral deflection of the beam are very small at the moment of the occurence of shear failure, which means that the finite deformation effect can be neglected in the shear failure analysis. Also, some aspects of the initial impact energy are investigated.  相似文献   

大鹏澳海域水体磷的形态及其分布特征     

彭云辉  王肇鼎 《热带海洋学报》1996,(2)

根据１９９２年１２月（冬季）和１９９３年７月（夏季）对大鹏澳海域２４ｈ定点连续观测和夏季大面调查，统计了该海域各种形态磷的变化范围和平均含量；计算了各种形态磷分别占总磷（ＴＰ）和总溶解磷（ＴＤＰ）的百分比；讨论了各种形态磷之间的相互关系；分析了影响ＴＰ和ＴＤＰ分布的环境因素。  相似文献   

Siltation Prediction for Navigation Channels and Harbour Basins on Muddy Beach   总被引：2，自引：0，他引：2  

Liu Jiaju Zhang Jingchao Prof. Senior Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing Senior Engineer  River  Harbour Department  Nanjing Hydralulic Research Institute  Nanjing 《中国海洋工程》1992,(2)

- This paper, after briefly reviewing the experimental research on sediment transport on muddy beach since the 1950s, improves and perfects the method for forecasting siltation in navigation channels and harbour basins which was first put forward in China by the authors. In consideration of silty sediment and sand, some factors in forecasting methods have been changed and modified. Consequently, the modified methods can be used either to compute siltation in navigation channels and harbour basins on muddy beach or to compute siltation and scouring in navigation channels and harbour basins on both silty beach and sandy beach. The verification of field data from eleven large, medium and small natural harbours shows a good agreement between the forecasting by the modified method and the natural conditions. Finally, the paper deals with the rational utilization of water area after the construction of the West Dyke in Lianyungang, the maintenance of water depth of the navigation channel at the entrance, siltation distribution, siltation in the navigation channel and harbour basin for ships of 100 thousand tonnnage. Results once again prove that the prospect of constructing Lianyungang Harbour into a deepwater harbour is bright.  相似文献   

Dynamic Analysis of a Single-Column Platform (II)     

Lian Gan  Ni Kan  Hu Kai Guo Dawei . Professor  Senior Engineer  Marine Design & Research Institute of China  Shanghai . Senior Engineer  Marine Design & REsearch Institute of China  Shanghai . Engineer  Marine Design & Research Institute of China  Shanghai 《中国海洋工程》1992,(4)

This paper describes the study of a single-column structure used as well-head platform. In order to check the reliability of computation theory and programme, model tests have been carried out. The paper introduces the conclusion of tests and the dynamic properties of single-column platform are obtained.  相似文献   

Elasto-Plastic Analysis of Tubular Joints of Offshore Platforms by Finite Element Method     

Chen Tieyun Zhu Zhenghong Professor  Dept. of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Lecturer 《中国海洋工程》1991,(1)

The plastic node method is reformulated by the variational principle and is applied to elasto-plastic finite element analysis of tubular joints, eventually including the effect of internal and external gussets, stiffener rings, etc., if necessary. Four different joints are studied here in detail for the elasto-plastic behavior, the strain at the hot spot, the strain concentration factor around the intersection line, and the propagation of the plastic region with loading up to collapse in order to determine the ultimate strength, safety factor, and development of the plastic field. The present results are in good agreement with the experimental results.  相似文献   

Wave-Current Forces on Slender Circular Cylinders   总被引：3，自引：0，他引：3  

Li Yucheng  Wang Fenglong  Kang Haigui Professor  Dalian University of Technology  Dalian Senior Engineer  Dalian University of Technology  Dalian Lecturer  Dalian University of Technology  Dalian 《中国海洋工程》1991,(3)

- A series model tests of wave forces by both regular and irregular waves combined with currents on single piles and bipiles in tandem and parallel arrays have been carried out. Based on Morison Equation, linear wave theory and linear wave spectrum theory as well, the characteristics of inline, lift and resultant forces on cylinders have been analyzed respectively. The drag, inertia and lift coefficients CD, CM and CL f皉 single piles related to KC number and the grouping effect coefficients of inline, lift and resultant forces on bipiles in tandem and parallel arrays related to KC number are given in this paper.  相似文献   

Numerical Simulation of Multi-Directional Random Seas     

Yu Yuxiu  Liu Shuxue  Li Li Professor  Dept. of Civil Engineering  Dalian University of Technology  Dalian Research Assistant  Dept. of Civil Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1991,(3)

Multi-directional irregular waves are simulated on the basis of the given directional spectrum using a double summation model, a single direction per frequency model and a single summation model. Their results are compared. It is shown that the single direction per frequency model proposed in this paper can generate a realistic wave field. The effects of the model parameters on the simulated results are also studied in this paper and corresponding suggestions are given.  相似文献   

Overtopping Discharge of Wind-Waves on Simple Slope Dikes     

Yu Kuang-ming  Zhang Jiachang  Zhou Jiabao Professor  Senior Engineer  The River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing Senior Engineer  The River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1991,(4)

An empirical formula for estimating the overtopping discharge of wind-waves on a smooth-impermeable-simple slope dyke is derived through model tests in this paper, it can be adopted by related design departments in the determination of the crest elevation of the dyke.  相似文献   

A Note on Soil Structure Resistance of Natural Marine Deposits   总被引：1，自引：1，他引：1  

洪振舜刘松玉  刘志方 《中国海洋工程》2004,18(2):321-326

It has been well documented that natural normally-consolidated marine soils are generally subjected to the effects of soil structure. The interpretation of the resistance of soil structure is an important issue in the theory study and engineering practice of ocean engineering and geotechnical engineering. It is traditionally considered that the resistance of soil structure gradually disappears with increasing stress level when the applied stress is beyond the consolidation yield stress. In this study, however, it is found that this traditional interpretation of the resistance of soil structure can not explain the strength behavior of natural marine deposits with a normally-consolidated stress history A new interpretation of the resistance of soil structure is proposed based on the strength behavior. In the preyield state, the undrained strength of natural marine deposits is composed of two components: one developed by the applied stress and the other developed by the resistance of soil structure. When the applied stress is beyond the consolidation yield stress, the strength behavior is independent of the resistance of soil structure.  相似文献   

Molecular identification of bloom-forming species Phaeocystis globosa (Pryninesiophyta) and its dispersal based on rDNA ITS sequence analysis     

Chen Yueqin  Shao Peng  Wang Ning  Zhou Hui  Qu Lianghu  Linda K. Medlin 《海洋学报(英文版)》2003,22(2):243-253

The colony-forming Phaeocystis species are causative agents of dense bloom occurrences in coastal waters worldwide. It is difficult to separate them because of the different morphologies associated with their colonial stages. In this study we applied molecular approaches to analyze the genetic variation of Phaeocystis globosa and Phaeocystis pouchetii from several geographic regions, and to assist in tracing the dispersal of bloom-forming Phaeocystis species in coastal waters of China. The sequences of the internal transcribed spacers (ITS1 and ITS2) of rDNA and the 5.8S ribosomal RNA gene of Phaeocystis strains were determined. Sequence comparison shows that P.globosa was the most divergent to P. pouchetii, exhibiting sequence divergence higher than 0.08. However, lower genetic divergences existed between strains of P.globosa. The sequence comparison of the Phaeocystis rDNA ITS clearly shows that the species isolated from the southeast coast of China is identified as P.globosa rather than P. cf. pouchetii or other species. Furthermore, the significance of rDNA variation in distinct global populations of P.globosa suggested it might have had sufficient time to accumulate detectable mutations at the rDNA locus, supporting the hypothesis of ancient dispersal of P.globosa to many areas, meaning that P.globosa blooms in the coastal waters of China are endemic rather than a newly introduced species or a foreign source. Finally, based on the high divergent region of rDNA ITS, a pair of species-specific primers for P.globosa were designed, they could be useful to detect the presence of this species in mixed plankton assemblages or flagellate stages that are recognized with diffculties by means of conventional microscopy.  相似文献