【作者】 赵强；

【导师】 刘海笑；

【作者基本信息】 天津大学 ， 港口、海岸及近海工程， 2007， 硕士

【摘要】 近年来,沉入式大圆筒结构在港口、海岸及近海工程领域得到了进一步的应用,与此同时,结构-波浪-海床耦合系统的稳定性分析研究已成为国内外科学研究中比较前沿性的课题之一。从以往的科研成果可以看出,仅仅对大圆筒结构进行静力稳定性分析是远远不能满足需要的。目前,国内外许多学者正对结构-波浪-海床耦合系统的动力失稳破坏机理进行进一步的研究。为了对结构-波浪-海床耦合系统进行动力稳定性分析,进一步加深对该耦合系统失稳破坏机理的认识,本文比照模型试验,基于MSC.Marc软件平台建立了该耦合系统的动力有限元计算模型。在模型中,通过二次开发,在将改进哈丁模型中的等效剪切模量和能表征软粘土在循环荷载作用下孔压发展变化规律的孔压模型引进Marc的基础上,采用了MSC.Marc Python中的PyMentat模块,将改进的哈丁模型中的等效阻尼比的变化进入算例,对结构-波浪-海床耦合系统进行动力响应分析,重点考察了阻尼的效应。此外,还将在材料动本构关系中较为常用的Ramberg-Osgood非线性无弹性模型引入数值模型中,对同一耦合系统进行了动力响应计算,并与哈丁等效线性化方法进行了对比,得到了一些有用的结论,对耦合系统的动力响应有了更深入的认识。本文的研究成果为以后此类结构系统的动力稳定性分析提供了成果上的积累,并为以后的相关研究提供方法上的支持。更多还原

【Abstract】 In recent years, embedded large cylinder has further application in harbors, coast and off-shore engineering, In the mean time, the stability analytical research of seabed-wave-structure coupling system is one of the frontier projects at home and abroad. From the previous study, we know that the merely static stability analysis of large cylinder structure is far from demand. At present, many scholars at home and abroad are further investigating the mechanism of instability and failure of seabed-wave-structure coupling system.In order to analyze the dynamic stability of seabed-wave-structure coupling system, to further understand the instability and failure of this coupling system, in the thesis we contrasted the model test and based on the MSC.Marc software we established the dynamic finite element computing model of this coupling system. In the model, through second development, we improved the equivalent cut model of Harden model and under the effect of cycle loading, the token soft clay made the development law of pore pressure. Based on this pore pressure model fetch in Marc, we adopted PyMentat module of MSC.Marc Python, put the change of equivalent Damping ratio of the improved Harden model into the examples, analyzed the dynamic response of the seabed-wave-structure coupling system, emphasized review on the damping effect.Furthermore, we introduced Ramberg-Osgood nonlinear nonelastic model that frequently used in dynamic constitutive relation of material into the data model, calculated the dynamic response to the same coupling system, contrasted with the method of Harden equivalent linear, made out some valuable conclusion and had further understanding to the dynamic response of the coupling system.The research results made out in the thesis provide accumulation to the dynamic stability analysis of the same kind of structure system and give methodological support to the correlative research.更多还原