柔性连接装置约束下的相邻浮体动力响应分析

Dynamic analysis of adjacent multiple floaters with flexible connections

许多海上工程作业中会出现两个或多个浮体相邻作业的情形,如海洋平台组块双船浮托安装等.在波浪作用下,相邻多浮体会发生水动力干扰现象,在特定条件下引起强烈的间隙共振,产生的巨大波浪力会对浮体造成破坏.相邻多浮体之间往往会存在柔性连接,需要考虑多浮体水动力干扰及机柔性连接构件的约束力对浮体运动响应的耦合作用,以及约束力本身对刚性或柔性连接构件的影响.因此,需要建立多浮体耦合的水动力-结构动力模型研究相互连接的海上浮式结构在复杂环境载荷下的动力响应.本文以双船浮托安装作业为背景,开发耦合的水动力-结构动力模型分析平台组块在双船拖运过程中的复杂动力响应.通过结合动态子结构法和静凝聚法,考虑连接构件的柔度,将连接构件的质量和刚度凝聚到构件与双船的连接点处.结合多浮体频域水动力分析,研究双船在柔性构件约束下和复杂水动力干扰共同作用下的运动响应.

Many offshore operations may involve two or more floaters operating in close proximity, such as the catamaran float-over deck installation for offshore platforms. The adjacent floating structures would experience hydrodynamic interactions under wave excitations.In addition, gap resonances may be induced under certain specific conditions and the resulting large wave forces may cause structural damage to the floaters. The adjacent floaters may be linked with flexible connectors. For this case, it is necessary to consider the coupled effects of hydrodynamic interactions and the constrained forces from the flexible connectors on the motions of the floaters as well as the effects of the constraint forces on the structural behavior of the connectors. Hence, a coupled multi-body hydrodynamic-structural dynamic model needs to be established to investigate the dynamics of interconnected floaters under the complex environmental loads. Taking catamaran float-over deck installation as the research background, this article develops a coupled hydrodynamic-structural model to analyze the complex dynamics arising from catamaran tow of the platform topsides. By combining dynamic substructuring and static condensation as well as considering the flexibility of connectors, the mass and stiffness of the connector are condensed to the connection points on the carrying barges. Based on the frequency-domain hydrodynamic analysis of the carrying barges, the dynamics of the barges are analyzed by considering the effects of both the multi-body hydrodynamic interactions and the constraint of the flexible connectors.