深海复合材料立管与海底管线在极端海洋环境联合作用下的非线性流固耦合振动和动力屈曲、后屈曲特性研究

According to characteristics of ocean engineering practise, nonlinear vibration and postbuckling analysis are presented for a shear deformable composite cylindrical risers and pipe-lines subjected to thermomechanical loadings in the deepwater environment. The governing equations are based on a higher order shear deformation shell theory with von Kármán-Donnell-type of kinematic nonlinearity and including the extension/twist, extension/flexural and flexural/twist couplings. A singular perturbation technique is employed to obtain the asymptotic solutions satisfying the governing differential equations with the boundary conditions and determine the buckling loads and postbuckling equilibrium paths. A boundary layer theory for the buckling, postbuckling and nonlinear vibration of anisotropic laminated and 3D braided thick shells is established and developed. Supported by grants from the National Natural Science Foundation of China (No. 50909059), 11 SCI journal papers including OCEAN ENGINEERING, COMPOSITE STRUCTURES, J ENG MECH-ASCE and J PVT-ASME are published and Excellent PhD Dissertation Award is obtained from Shanghai Municipal Education Committee, in 2010.. A new mechanical model of non-linear solid-fluid interaction vibration and dynamic buckling, postbuckling character of composite risers and submarine pipelines in deepwater subjected to combined extreme sea environment loading are established. Chaotic character of ocean currents and waves and modal coupling effect are both taken into account. The solutions presented give an insight into interaction between non-linear solid-fluid interaction dynamic character and response mechanism of composite pipe-lines in deepwater. The present study is capable of providing which may be helpful for the further study in the design of the composite risers and submarine pipelines subjected to combined extreme sea loading in deepwater environment.

针对深海复合材料管线服役特点，对复合材料管线在环境和机械载荷作用下的后屈曲行为和非线性大挠度振动特性作了系统的研究，给出在渐近意义上严格满足边界条件的后屈曲和非线性振动的大挠度渐近解，发展和建立了计及横向剪切和刚度耦合效应在内的完全各向异性剪切圆柱壳屈曲和振动的边界层理论。录用和发表包括国际期刊OCEAN ENGINEERING、COMPOSITE STRUCTURES、J ENG MECH-ASCE和J PVT-ASME期刊等在内的第一作者SCI论文12篇，获得2010年度上海市优秀博士学位论文奖。.研究深海环境下海流和波浪等载荷对海底管线和立管的作用规律，采用解析法与数值解法相结合的方法，给出复合材料管线与立管非线性流固耦合振动和动力屈曲的大挠度解，通过参数分析揭示深海环境下复合材料管线和立管非线性动力屈曲和流固耦合振动特性的作用机理，为复合材料管线结构抑振和稳定性设计提供理论支持。

项目以深海复合材料立管和海底管线为研究对象，建立三维编织和各向异性层合复合材料板壳梁结构为力学模型，综合考虑环境载荷、 横向剪切变形和几何非线性的影响，系统地研究了结构在热环境中的后屈曲、非线性振动、非线性弯曲和非线性热瞬态响应等问题。引入壳体屈曲的边界层理论，研究三维编织和各向异性层合复合材料壳体结构的屈曲、后屈曲和非线性振动行为，建立了一套系统分析热环境中壳体结构非线性问题的求解方法，丰富和发展了结构非线性分析的方法和理论。 将位移场按照Laurent 级数展开，得到了可以精确描述三维编织和纤维增强层合圆管内外表面应力边界条件和几何形状的高阶剪切模型，通过广义变分原理建立了热环境中复合材料圆管后屈曲和非线性振动问题的微分控制方程，并通过二次摄动法和Galerkin积分相结合进行求解。讨论了横向剪切变形、材料的温度相关性、纤维体积含量和圆管内半径等对复合材料圆管热屈曲和热后屈曲的影响。 基于已得到的高阶剪切梁理论，利用Hamilton 变分原理，建立了热环境中复合材料圆管的非线性振动和非线性弯曲问题的控制方程，并采用二次摄动法进行求解。讨论了横向剪切变形、材料的温度相关性、弹性基础、圆管内半径和热环境对复合材料圆管的非线性幅频响应和非线性弯曲响应的影响。.在该基金项目的资助下，共发表SCI收录论文15篇，其中第一和通讯作者论文14篇。