考虑流固耦合作用的深水桥墩地震响应分析

地震作用下,深水桥墩与周围水体的耦合振动是一个非常复杂的动力相互作用问题。本文基于非线性Mori-son方程,采用Airy波浪理论,建立了深水桥墩考虑流固耦合作用的有限元模型,应用Newmark-β法提出了求解该耦合非线性方程的算法,并用ANSYS软件和Matlab软件自编了求解程序。以某跨海大桥深水桥墩为算例,对其进行在地震作用下的非线性动力分析,并与已有计算方法进行对比。结果表明:按本文方法计算的墩顶最大位移、墩底最大剪力及墩底最大弯矩均较大,差异最大达到12.5%。因此在极端海况条件下,对深水桥墩进行地震作用下的动力分析时,建议采用本文考虑流固耦合的方法。

Seismic Response Analysis of Piers in Deep Water Considering Fluid-Structure Interaction

In the seismic response analysis of deep-water bridges,it is complex to study the coupling effect if the pier-water interactions are considered.Therefore,in this paper,taking the Fluid-solid coupling effect into account,a FEM model of deep-water pier is established based on the nonlinear Morison equation and Airy wave theory.To solve the nonlinear coupling equation,a new algorithm is proposed with Newmark-β method,and a improved procedures is applied by Ansys and Matlab nonlinear software.Furthermore,with an actual deep-water pier example,the famous Morison Equation is used to analyze hydrodynamic pressure where as a simplified method the water is considered as the added pseudo mass.The results show the seismic responses of bridge pier is notable whether considering the effect of hydrodynamic pressure or not,and the hydrodynamic pressure can remarkably change the occurrence time of earthquake response peak value.While the seismic performance determined by the new way is compared with the old methods,the main conclusions indicate that the maximum displacement of the pier top、the maximum shear and the moment of the pier bottom are all greater,the maximum error of which is up to 12.5%.So the dynamic water has great effect on seismic response of deep-water bridges,and it is necessary to use the new proposed method to study the dynamic analysis of deep-water bridges under earthquake effect.