【摘要】 在深水桥墩及桩基础等结构地震反应中,地震激励下的水流动水压力对水中结构的作用以及结构位形变化对水体的反作用,属于典型的流固强界面耦合问题。以一顶端伸出水面的圆柱式结构为研究对象,基于任意拉格朗日-欧拉描述的Navier-stokes方程,建立了考虑水流-结构强耦合效应的水流-结构三维有限元模型。以正弦位移波输入,考察结构材料模量、水流流速和水位、激振频率和位移幅值等多种因素,分析了结构表面作用的动水压力反应特征以及水流动力效应,探讨了水流动力效应的主要影响因素。结果表明:考虑流固强耦合作用时,结构表面作用的动水压力及其分布具有强烈的频率依赖性,高频激励可显著增强动水压力作用;由于结构周围流体具有一定的粘滞性及动载作用下具有较强的辐射阻尼效应,水流动力效应对结构的位移、内力反应均有一定的抑制作用;激振频率、水流流速和水位以及结构材料模量等因素,对水流动力效应均有一定的影响。更多还原

【Abstract】 For the responses of bridge piers and pile foundations in deep water during earthquakes,hydrodynamic pressures of the waterflow acting on the structure and back action of structure deformation on waterflow belong to the classical close fluid-soild interface coupling.A 3D close waterflow-structure coupling finite element model is established,in which the Navier-Stokes equation described by arbitary Lagrange-Euler format is employed to control the waterflow movement.Dynamic responses of cylindrical structres with the top out of the water during the excitation of sine wave are investigated.The hydrodynamic pressure behaviour of the waterflow acting on the structure and dynamic effects of the waterflow are analyzed.The results indicate that the distributions of hydrodynamic pressures are dependent on the excitation frequency strongly.High frequency excitations may intensify the action of hydrodynamic pressures on the structure.The dynamic effects of waterflow may restrain the displacement and inner force responses of structures because of the viscosity and radiation daming of the waterflow.Some main factors including the structure modulus,velocity of waterflow,water height,excitation frequency and amplitude are discussed.更多还原