Parametric Analysis and Experimental Study on Local Flexibility of TY-Type Tubular Joints     

XuHantao Chen Bozhen HuYuren Pan Hao 《中国海洋工程》1996,(1)

Loal flexibility of tubular joints has important effect on the static and dynamic behaviour of offshore platforms, therefore, the determination of it becomes an important research subject in the field of offshore engineering. In this paper, the local flexibility of TY-type tubular joints, which are widely used in offshore platforms, is calculated by using semi- analytical method. Based on the calculated results, parametric formulae for evaluating element in the local joint flexibility matrix of TY- type tubular joints are derived by regression. A test on PVC models of TY-type tubular joints to measure the local joint flexibility is also reported. A comparison of the results calculated from the parametric formulae presented in this paper with those measured from the model test shows that the parametric formulae are reliable. It is recommended that these formulae be used in the global structural analysis of offshore platforms.  相似文献   

Wells turbine with end plates for wave energy conversion   总被引：1，自引：0，他引：1  

Manabu Takao  Toshiaki Setoguchi  Yoichi Kinoue  Kenji Kaneko 《Ocean Engineering》2007,34(11-12):1790-1795

In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plate on the turbine characteristics has been investigated experimentally by model testing. As a result, it is found that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine, i.e., the turbine without end plate and the characteristics are dependent on the size and position of end plate. Furthermore, by using a computational fluid dynamics (CFD), reason of the performance improvement of the turbine has been clarified and the effectiveness of the end plate has been demonstrated.  相似文献   

Comparison between a U-OWC and a conventional OWC     

Paolo Boccotti   《Ocean Engineering》2007,34(5-6):799-805

With an additional vertical duct at the wave-beaten side, an OWC is expected to give some much better performances. This is, essentially, due to two reasons. First, an OWC with the additional vertical duct (U-OWC) has an eigenperiod greater than the eigenperiod of a conventional OWC. Second, the amplitude of the pressure fluctuations on the opening of a U-OWC is greater than the amplitude of the pressure fluctuations on the opening of a conventional OWC (the greater the smaller the wave period is). For the first reason, a U-OWC can give performances better than those of a conventional OWC both with swells and large wind waves. For the second reason, a U-OWC can give performances better than those of a conventional OWC also with small wind waves.  相似文献   

The Stress Concentration of Multiplanar Tubular Joints of Offshore Structure     

Chen Tieyun  Zhang Huiyuan Proefessor  Shanghai Jiao Tong University  Shanghai Engineer  Shenzhen Shipbuilding Trading Co. LTD  Shenzhen 《中国海洋工程》1993,(4)

- The formulation for the stress concentration matrix of multiplanar tubular joint with braces subjected to combined load is established in this paper. The formulations for SCF values of multiplanar tubular joints are compared with those by Wordsworth and Efthymiou. The stiffening effect and load-interaction effect are discussed. A spatial offshore jacket with braces subjected to combined load is computed as a numerical example. The maximum stress of each multiplanar tubular joint and its location are found through SCF matrix. Finally, the difference between the maximum stresses of multiplanar tubular joints and their corresponding uniplanar tubular joints are discussed.  相似文献   

Structural Analysis of Platforms with the Effect of Joint Flexibility     

Mu Yang Zhang Shengkun Assistant  Dept. of Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Professor  Dept. of Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1993,(3)

- A modified space beam element is presented in this paper to consider the local joint flexibility of T, Y tubular joints subjected to axial forces and in- plane bending moments for analysis of platforms. Two numerical examples are shown to verify the efficiency and validity of the method presented here.  相似文献   

不同放养密度和混养石莼对牙Ping鱼种生长的影响   总被引：1，自引：0，他引：1       下载免费PDF全文

王吉桥  李岩 《海洋科学》2003,27(2):1-4

牙鲆的放养密度以所放养鱼腹面表面积之和占养殖池底面积的百分数 ( % )表示。在直径为27cm、容积为40L的塑料桶中放置网箱 ,按网箱底面积48 % ,74 %或100 %的密度放养牙鲆 (Paralichthysolivaceus)幼鱼 (体质量1.86g±0.18g,全长6.3cm±0.27cm)。同时另在放养密度100%组中混养石莼40.00g。经45d饲养 ,混养石莼组中的牙鲆生长最快 ,水质好 ,饲养系数最低。在单养组中 ,牙鲆生长速度由快至慢依次为48 %组>74%组>100%组。牙鲆体长增长和体质量增长速度最快的密度分别为80 %～100%和100%～110 % ,低于或高于此密度鱼的增长均减慢。  相似文献   

The joint long-term distribution of design environmental factors for offshore structures Multivariate probabilities and simulating method     

Shi Jiangang  Liu Defu  Wang Zheng 《海洋学报(英文版)》1993,12(3):465-474

With the development of ocean engineering, it is one of the most important factors which determine the structural safety, cost and suitable forms of engineerings to select the ocean environmental design criteria. Owing to the complexity , variation and randomness of ocean environmental conditions, the commonly used methods for determining design criteria cannot consider the joint occurring probabilities of several environmental factors ,therefore, lead to overestimate design criteria of them and result in an unnecessary overspend invest in engineering. On the basis of the measured and hindcasting data and the multi-demension joint probability theory, this paper presented the study of the joint loads of wind , wave and current on the offshore structures and its responsible joint probability level with the application of random simulation techniques, and presented the joint design criteria of environmental loads for the realistic design of engineerings.  相似文献   

海洋立管综合环境条件设计标准研究     

刘德辅  王树青等 《海洋工程》2001,19(2):13-17

首先用有限单元法推导海洋输液立管在外界环境荷载条件下的侧向振动微分方程。对渤海某海区的15次风暴过程作了抽样分析，得到以波高为主时的波高、流速序列和以流速为主时的波高、流速序列，并对其进行了Weibull、Gumbel、Lognormal等适线分析，以确定各序列的最优分布形式及相应的特征值。用重点抽样法进行随机模拟得到联合概率为百年一遇的波高的流速。针对线海固定式平台铰接的海洋输液立管，以最大应力为控制条件确定其联合设计标准，并与其它方法作了比较，得到一些有益的结论。  相似文献   

Truss Spar平台桁架管节点疲劳分析     

陈鹏耀  薛鸿祥  唐文勇  张圣坤 《海洋工程》2007,25(2):15-20

Truss Spar平台在风、浪、流的作用下,结构受力十分复杂,准确分析其疲劳强度相当困难。通过建立Truss Spar平台三维有限元模型,利用HydroD软件进行载荷预报、波浪搜索,得到产生最大应力幅响应的最不利浪向和相位角。运用Sestra软件进行整体有限元分析,得到的结果作为桁架管节点细化模型的边界条件,再用Nastran软件进行局部分析求得节点的热点应力,修正壁厚影响。最后根据DNV规范的S-N曲线计算了管节点的疲劳寿命。  相似文献   

Constructing a coherent joint prior while respecting biological realism: application to marine mammal stock assessments   总被引：1，自引：0，他引：1  

Brandon  John R.; Breiwick  Jeffrey M.; Punt  Andre E.; Wade  Paul R. 《ICES Journal of Marine Science》2007,64(6):1085-1100

  相似文献