波浪与开孔结构相互作用问题的比例边界有限元方法研究

The porous structures have been considered for the sake of good effect on reduction of wave force and wave run-up around the outside of the structure. Many researchers have investigated the interaction wave with porous structures. However, due to the complexity of this problem, the previous studies are still not sufficient. For example, there is little literature has been report on wave interaction with porous structures by thinking about more complex geometry,nonlinear waves and porous structures’ movement. In this program, a new semi-analytical numerical method called scaled boundary finite element method (SBFEM), which has higher accuracy and efficiency, has been applied to the wave interaction with porous structures. The main works contain: The models of scaled boundary finite element method for wave interaction with porous structures with arbitrary complex geometry have been established. Then, the influences of the wave parameters, the configuration and material properties of the structures on the systems hydrodynamics, including the wave force, wave and diffracted wave contour are extensively examined in details, and Some Parameters on the disspiating waves are also investigated; A quadratic law (not linear) relating the pressure differential to the traversing velocity is assumed, and the hydrodynamic characteristics of the porous structures is analyzed by SBFEM in detailed; The influences of nonlinear wave on the hydrodynamic characteristics of the porous structures has been revealed; Movements such as swaying, heaving and rolling on the hydrodynamic characteristics of the structures have also been analyzed in details. This program can deepen the understanding for the wave interaction with porous structures and expand its theory.

开孔结构由于具有良好的减小波浪反射和自身所受波浪力的特性，越来越多地受到人们的重视。但开孔结构的消浪机理十分复杂，这其中仍存在大量亟需解决的问题，如考虑任意几何形状、非线性波浪、开孔结构运动以及开孔壁两侧压力呈非线性关系等对开孔结构水动力特性的影响尚少见报道。本项目基于具备高精度和高效率的比例边界有限元法深入研究波浪与开孔结构物相互作用问题。项目的主要研究内容包括：建立具有任意几何形状的开孔结构水动力特性的比例边界有限元模型；在此基础上，对影响开孔结构水动力特性的因素（包括波浪参数、结构物的几何、材料参数等）进行详细分析，并研究这些参数对消波、防波效果的影响进行分析；基于壁面压差与法向速度呈二次关系边界条件进行理论和数值分析；揭示非线性波浪对开孔结构荷载的影响规律；分析开孔结构分别做横荡、垂荡、横摇等运动时对结构所受波浪力等的影响。本研究工作的开展可加深了解波浪与开孔结构相互作用的机制。

本项目针对开孔结构的消浪机理十分复杂特性，基于比例边界有限元法建立了开孔结构在海浪里及液箱里晃荡的水动力特性研究的高效分析模型；开展了开孔结构的参数对消浪、防波效果影响分析；开展了开孔结构壁面压差与法向速度呈二次关系边界条件的理论分析；建立了非线性液体晃荡的比例边界有限元方法模型；分析了开孔结构运动时对结构所受波浪力等的影响。以上研究开展加深了解波浪与开孔结构相互作用的机制。以此同时，大坝、核电站、大跨桥梁、高层建筑及海洋钻井平台等重要结构物多建于复杂地基上，其安全性至关重要。考虑结构与复杂无限地基的动力相互作用分析方法是开展这类大型结构抗震安全评价的关键问题。而该问题和以上研究内容在方程形式类似，为此本项目进一步建立了基于结构与复杂地基相互作用全时域高效比例边界有限元数值算法；提出了求解复杂成层材料静动力响应的精细积分与混合变量结合的高效数值模型。同时利用以上成果拓展到交差学科如建立了层状压电材料的精细积分方法；提出了磁电弹板问题的高效SBFEM求解方法；建立了等几何比例边界有限元方法求解热传导、热应力及其渗流问题的高效模型。以上研究成果对结构安全评价具有重要的科学意义与研究价值。