U形渡槽流固耦合动力作用研究

为了研究强震下渡槽的流固耦合动力作用,本文首先用VOF模型验证了渡槽内水体响应的非线性,然后通过位移有限元方法建立了U形渡槽流固耦合模型,并根据地震作用的特点构造了一组Ricker子波,分别计算了刚、柔性槽体模型的动力时程响应。计算结果表明,渡槽流固耦合动力作用的强度主要受流体晃动频率、槽体自振频率两个因素控制,当外界激励的频率接近这两个频率时,渡槽的流固耦合动力作用将变得十分显著;当激励频率达到水体晃动频率的2倍时,水体主要运动方式将由表面晃动转变为整体惯性运动;地震作用下水体动力响应的非线性可以忽略。这些现象在渡槽抗震设计中应当引起足够的关注。

Fluid-structure coupling effect of U-shaped aqueduct

In order to study fluid-structure dynamic interaction of aqueducts under strong earthquakes,the VOF model is used to verify the nonlinearity of water response in aqueduct. A Lagrange finite element method formulated by displacement is used for fluid-structure coupling modeling of a U-shaped aqueduct. Time-history analysis of both rigid and flexible aqueduct wall is made by applying a group of Ricker waves designed with the characteristics of earthquake action. The results show that the intensity of fluid-structure coupling effect is decided by water sloshing and aqueduct wall frequencies,and the fluid-structure coupling effect becomes stronger when load frequency gets closer to them. Besides,motion mode of water changes from surface sloshing to global inertia movements when load frequency gets 2 times the water sloshing frequency and nonlinearity of fluid-structure coupling effect can be ignored under seismic influence. More attention should be paid to all these results in aqueduct seismic design.