钢筋混凝土梁结构断裂损伤诊断方法     

周尚志  王丽华刘瑛 《海洋工程》2005,23(4):47-51

提出一种基于BP神经网络的结构破损诊断方法,该方法以结构破损前后柔度的变化作为破损诊断网络输入,为了解决由于系统响应样本数据空间分布不均匀对网络收敛速度及网络诊断影响问题,对网络训练样本采用广义空间格点进行了交换,模拟算例及应用实例均表明,本文方法能准确诊断结构破损位置与破坏程度,是一种有效的结构破损诊断方法.  相似文献   

Long-Term Effect of TMD on Vibration Control of An MDOF Offshore Fixed Platform     

SHI  Xiang 《中国海洋工程》2003,17(4):481-494

A three-dimensional fixed offshore platform in deep water modeled by the finite element method is studied in this paper. Analysis of the dynamic response of the MDOF structure is realized taking the non-linearity of the wave drag force and the wave-structure interaction into account. The structural response statistics, which have Gaussian distributions, are used to evaluate the vibration effect of the structure without TMD and with TMD. And an optimal method to design TMD controlling the first mode of the multi-mode structure is proposed. Moreover, the probabilities of occurrence of sea states at the platform site are considered for prediction of the long-term effect of a TMD. Simulation results demonstrate that the long-term effect of a well-designed TMD is good and the practical use is possible due to the good stability of its optimal parameters under different sea states.  相似文献   

Reliability-Based Optimal Design for Very Large Floating Structure     

张淑华 《中国海洋工程》2003,17(1)

1 .ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｐｐｒａｉｓａｌｏｆａｇｏｏｄｄｅｓｉｇｎｆｏｒａｖｅｒｙｌａｒｇｅｆｌｏａｔｉｎｇｓｔｒｕｃｔｕｒｅ(ＶＬＦＳ)ｔｈａｔｗｉｌｌｓｅｒｖｅｉｎａｓｐｅｃｉ ｆｉｅｄｏｃｅａｎａｒｅａｒｅｑｕｉｒｅｓｔｈａｔｔｈｅｓｔｒｕｃｔｕｒａｌｓｙｓｔｅｍｂｅｅｃｏｎｏｍｉｃａｌｌｙｄｅｓｉｇｎｅｄ ,ｔｈｅｒｅｑｕｉｒｅｍｅｎｔｓｆｏｒｉｔｓｆｕｎｃｔｉｏｎｂｅｓａｔｉｓｆｉｅｄａｎｄｔｈｅｓｔｒｕｃｔｕｒｅｋｅｅｐｓｓｔａｂｌｅｉｎｉｔｓｗｈｏｌｅｓｅｒｖｉｃｅｐｅｒｉｏ…  相似文献   

软粘土中插入式大直径薄壁圆筒结构的一种极限状态分析模型     

王乐芹  周锡礽  张伟 《海洋技术学报》2005,24(1):95-100

根据插入式大直径薄壁圆筒结构的工作特点建立了其合理的破坏机制，以此为基础建立了受横向荷载作用的插入式大直径薄壁圆筒结构的上限法极限分析模型，从中可以得到作用于插入式大直径薄壁圆筒结构上的横向极限荷载近似的上限解；并根据上限法模型计算结果，提出了计算受横向荷载作用的插入式大圆筒结构侧壁极限抗力的简化修正模型，利用此修正模型，基于极限平衡法，可以求解作用于插入式大直径薄壁圆筒结构上的横向极限荷载。  相似文献   

Stability Design System of Submarine Pipelines     

Gao Yinli Yan Shuwang Wang Jinying Graduate Student  Tianjin University  Tianjin Professor  Tianjin University  Tianjin Senior Engineer  China Offshore Oil Engineering Co. 《中国海洋工程》1995,(1)

This paper introduces a stability design system of submarine pipelines. The system can provide a reasonable design procedure for users with reference to domestic and foreign methods and in the light of home engineering experience.  相似文献   

确定连续系统参数的时域方法     

刘若峰  胡沂清 《中国海洋大学学报(自然科学版)》1995,(Z1)

提出一种确定连续系统参数的时域方法。该方法利用方波输入和系统稳定性，离析出输出采样信号与结构参数的内在联系，推导出确定连续系统结构参数的算法．指出该算法与辨识方法相结合，可实现对含随机干扰的连续系统结构参数的估计．  相似文献   

Nonlinear coupled dynamic response of offshore Spar platforms under regular sea waves     

A. K. Agarwal  A. K. Jain 《Ocean Engineering》2003,30(4):492-551

Many innovative floating offshore structures have been proposed for cost effectiveness of oil and gas exploration and production in water depths exceeding one thousand meters in recent years. One such type of platform is the offshore floating Spar platform. The Spar platform is modelled as a rigid body with six degrees-of-freedom, connected to the sea floor by multi-component catenary mooring lines, which are attached to the Spar platform at the fairleads. The response dependent stiffness matrix consists of two parts (a) the hydrostatics provide restoring force in heave, roll and pitch, (b) the mooring lines provide the restoring force which are represented here by nonlinear horizontal springs. A unidirectional regular wave model is used for computing the incident wave kinematics by Airy’s wave theory and force by Morison’s equation. The response analysis is performed in time domain to solve the dynamic behavior of the moored Spar platform as an integrated system using the iterative incremental Newmark’s Beta approach. Numerical studies are conducted for sea state conditions with and without coupling of degrees-of-freedom.  相似文献   

筒型基础沉贯阻力估算方法   总被引：1，自引：0，他引：1  

何炎平 《海洋工程》2002,20(3):23-28

系统地总结国外有代表性工程实践对筒型基础沉贯阻力的研究 ,并将各种方法综合起来 ,提出了加权综合估算法 ,供今后的研究和工程实践参考  相似文献   

浅海桶形基础平台抗拔力与抗倾稳定分析     

薛万东 《海洋科学进展》2001,19(3):87-92

平台在海上受风、浪、流、冰等水平载荷作用产生倾斜 ,而土壤粘接力、摩擦力和土抗力是平台的抗拔和抗倾力 ,桶基平台应满足抗拔、抗倾稳定的要求 ,以保证平台的整体稳定性。讨论了桶基平台受水平力作用时 ,桶形基础的破坏模式及其计算方法 ,阐述了抗倾稳定计算方法  相似文献   

Associations between Atlantic cod (Gadus morhua) and hydrographic variables: implications for the management of the 4VsW cod stock     

Smith  Stephen J.; Page  Fred H. 《ICES Journal of Marine Science》1996,53(3):597-614

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