Local Joint Flexibility Multibrace Tubular Joints     

Chen Tieyun Zhang Huiyuan Professor  Shanghai Jiao Tong University  Shanghai Engineer  China State Shipbuilding Corp.  Shenzhen Shipbuilding Trading Co. Ltd. 《中国海洋工程》1993,(2)

The local joint flexibility matrix of multibrace tubular joints (uniplanar and multiplanar joints) is defined. The formulation for computing the elements of local flexibility factor matrix of multibrace tubular joints by semi- analytic method is presented in this paper. The stiffening effect of unloaded braces and cross-flexibility between braces are discussed. Using the local flexibility of unibrace joints instead of that of multibrace joints in conventional structural analysis will lead the result to an unsafe side.  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   

Dynamic Analysis of a Single-Column Platform     

Lian Gan  Ni Kan  Hu Kai  Guo Dawei Prof.  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》1991,(4)

In this paper, a single-column structure used as well-head platform is studied. The loads of wave and current exerted on the single-column will be greatly reduced, therefore the cost of the structure will be decreased. The advantages of the single-column structure compared with ordinary jacket structure are explained. A dynamic analysis of this type of structure is made and some problems related to dynamic analysis are solved. In order to check the reliability of computation theory and programme, model tests have been carried out. However, as space is limited, the conclusion of tests will be introduced in another paper. Therefore, this type of structure is applicable for proctical engineering.  相似文献   

地震现场预报数据处理系统     

黄冰树  庄昆元等 《地震》1995,(2):125-130

地震现场预报数据处理系统是供分析预报人员在地震现场使用的一套实用性计算机软件。该系统根据国家地震局颁布的《地震现场工作大纲和震情分析指南》及目前在地震现场预报中常用的各类方法编制了相应的程序,并结合实际工作需要研制了该数据处理系统。它既是一个独立的完整的系统,又可以作为一个子系统与专家系统、数据库系统紧密地结合成一个功能更强的地震现场预报专家咨询系统。该系统主要有三大方面的功能模块：（1）计算机自动处理;（2）用户选择运行;（3）震前活动参数的计算。  相似文献   

Stress Analysis of Spatial Non-Concurrent Tubular Joints   总被引：1，自引：0，他引：1  

ChenTieyun  Wu Zhengqi Professor  Shanghai Jiaotong University  Shanghai P. h. Doctor  Shanghai Jiaotong University  Shanghai 《中国海洋工程》1994,(4)

The formulations of analytic-numerical method for the stress analysis of non-concurrent spatial tubular joints are introduced in the paper. The spatial DT joints with different eccentricity in the vertical diametrical plane of chord are computed. Finally the influence of eccentricity on the stress at possible hot spots is discussed.  相似文献   

A Model for Loadout Analysis and Its Programming Implementation     

Zhong Wanxie  Yao Shizhong Wu Lianyuan  Xi Deyin Professor  Shanghai Jiao Tong University    Shanghai Engineer  Shanghai Jiao Tong University    Shanghai Lecturer  Shanghai Jiao Tong University.  Shanghai 《中国海洋工程》1993,(4)

- In this paper, the authors use the finite element method to conduct a special static analysis for the loadout procedure of offshore structures. By introducing a variable Xmove (the distance between the relative coordinate system fixed in the moving upper structure and the absolute coordinate system fixed on slideway), adopting substructure to treat the upper structure, and using the elastic foundation beam to model the slideway, the model for the analysis of the loadoul procedure is established. On the basis of this model, DASOS-J loadout program, a program system for the static analysis of loadout offshore structures, is also developed.  相似文献   

Influences of microbial communities on groundwater component concentrations during managed artificial recharge     

Wenjing?Zhang  Ying?Huan  Dan?Liu  Hanmei?Wang  Xun?Jiao  Xiancang?Wu  Shanghai?DuEmail author 《Environmental Earth Sciences》2016,75(1):84

Managed aquifer recharge is one of the most popular methods for dealing with local water shortage issues, and the bacterial community could be a vital factor influencing groundwater quality during this process. In this study, analysis of variations in groundwater components during artificial recharge revealed three stages at a text site in China. During stage I, total iron and dissolved organic carbon levels are stable basically, dissolved oxygen and SO₄ ^2? levels have rising trends, NO₃ ^? curve varied not obviously. Variation curves show increases in dissolved oxygen, NO₃ ^?, SO₄ ^2? and stabilization in dissolved organic carbon and total iron at stage II. During stage III, dissolved oxygen and NO₃ ^? have rising trends, dissolved organic carbon, total iron, and SO₄ ^2? keep stable. At 25 and 70 days the Simpson and Shannon–Wiener indices show that microbial community richness and population diversity underwent a gradual dynamic change after recharge water arrived. Correlation analysis shows that the Simpson index was mainly affected by dissolved oxygen and NO₃ ^?. PCR-DGGE confirmed these findings. Overall, the results revealed that the main bacterial communities reduce total nitrogen, total phosphorous, and chemical oxygen demand, which corresponded to the calculated correlation index.  相似文献   

南海北部17937岩心四万年来古环境变化的分子有机地球化学记录   总被引：4，自引：0，他引：4  

李丽  王慧  汪品先 《地球科学》2008,33(6):793-799

以分子有机地球化学为手段对南海北部四万年来的古环境古气候研究表明, U₃₇k’-SST表层水温在冰期、间冰期平均范围分别为27℃和24℃, LGM与全新世温差达4.5℃; 以高分子量烷烃所代表的陆源物质输入和长链不饱和酮化合物所代表的海洋初级生产力都呈现冰期高、间冰期低特征, 表明冰期时陆源物质输入的增加和海洋表层生产力的提高; 正构烷烃C₃₁/C₂₇记录了南方大陆的植被由冰期时草本植物占优势向间冰期时木本植物占优势的转变.说明南海在末次冰期以来气候的不稳定性, 和海陆生态系统对气候变化的响应以及分子有机地球化学在古环境古气候研究中的巨大潜力.   相似文献   

南海南部普林虫与“中更新世革命”   总被引：6，自引：2，他引：4  

徐建汪品先  黄宝琦翦知湣 《地球科学》2004,29(1):7-14

对南海南部ODP 1143站2.1 Ma以来沉积物中的浮游有孔虫群进行研究, 发现在冲绳海槽及南海北部普遍被认为是黑潮标志种的Pulleniatina obliquiloculata在中更新世革命(MPR)前后对冰期旋回的响应截然相反; 且在MPR之后的变化与南海北部和冲绳海槽相反, 即冰期时含量高而间冰期时低.交叉频谱分析和相位分析的结果也证实了ODP 1143站P.obliquiloculata与全球冰量变化之间的上述关系.该种在MPR前后冰期旋回的转变, 可能是由于MPR之后南海南部在冰期时切断了与印度洋之间的海水交换, 或者是冰期时海水盐度增加等因素引起的上部水体结构的重大改观所致.   相似文献