基于离散模块梁单元理论的超大型浮体在非稳态载荷下的水弹性响应

使用离散模块梁单元(Discrete-Module-Beam, DMB)理论计算超大型浮体在非稳态载荷下的水弹性，包括位移响应和结构力响应。使用三维势流理论进行水动力分析，并基于Cummins方程将DMB方法扩展至时域；使用子梁法进行位移响应还原。在求解结构力响应时，结构被视作无支持、两端自由的无质量梁，将其所受外载荷按沿结构纵向分布是否已知划分为2类。对于已知分布的外载荷，直接对其进行积分即可获得结构力分布；对于未知分布的外载荷，使用改进后的三次曲线插值法求解结构力分布。计算定点货物移动和飞机降落工况下的水弹性响应。采用DMB方法可准确计算结构位移响应，也可给出非稳态加载过程中初始阶段的弯矩分布，并体现由集中力作用引起的弯矩突变。

Hydroelastic Response of VLFS Under Unsteady External Loads Based on Discrete Module Beam Method

The Discrete-Module-Beam (DMB) method is applied on a Very Large Floating Structure (VLFS) to perform a hydroelastic analysis under unsteady external loads, including displacement response and structural force response. The hydrodynamic analysis is performed by three-dimensional potential flow theory, and the DMB method is extended to the time domain based on the Cummins equation; the displacement response is restored by the sub beam method. The structure is viewed as a massless free-floating beam, whose external loads are divided into 2 groups according to whether the distribution is known or not. The structural force distribution induced by loads whose distributions are known is obtained directly with an integration of these external loads. For the loads with unknown distribution, a third-order interpolation scheme is implemented after some processing on the original hydroelastic equation. A cargo dispatch case and a plane landing case are calculated. The DMB method is able to give the accurate structural displacement response and bending moment distribution in the initial stage of the loading process and shows an abrupt change on the location where a concentrated force is exerted.