中文摘要：

流体固体动力耦合是众多工程领域的重要问题。由于流体与固体动力特性的巨大差异，二者的耦合研究异常困难，尤其是三维领域的研究更加复杂。本文分析了三维流体、固体接触界面上的运动状态，提出并采用流体固体接触界面的无限点对模式，模拟流体固体的动力相互作用。并利用广义变分原理结合Lagrangian乘子法，引入流体固体接触面约束条件，建立了三维不可压缩流体与固体动力耦合统一分析的理论模型，继而推导了耦合后的动力有限元求解方程，首次将流体与固体动力耦合内力作为未知量求解，使耦合后的流体与固体域的瞬态动力响应从同一方程中解出。经典算例较高的计算精度表明了这种耦合模型的正确性。液体储存箱的地震反应结果表明，固体变形的动力效应是显著的，应引起工程设计的注意。

英文摘要：

Fluid-solid dynamic interaction is a significant problem in the area of engineering, but it is diffi- cult to study on their coupling analysis due to dramatic differences between fluid and solid, especially on 3-D analysis. This paper analyzes interface＇s motion status of tri-dimensional fluid and solid, proposing and applying infinite dot pair＇s mode on interface to simulate fluid-solid dynamic interaction. Moreover, ac- cording to the generalized variational principle and Lagrange multiplier method this paper introduces flu- id-solid interface constraint condition and establishes theoretical model that could analyze dynamic interac- tion about tri-dimensional uneompressed fluid and solid. Then it deduces coupling dynamic finite element equation and treats fluid-solid dynamic coupling internal force as unknown which allows dynamic transient response of coupling fluid domain and solid domain could be deduced from the same equation. The results of a classic example indicate that this model is correct and has relatively high accuracy in calculation. The earthquake response of fluid tank indicates that solid deformation is dramatic and should be considered in engineering designing.