Research On Structural Equivalent Dynamic Analysis Method Considering Fluid-structure Interaction

Water energy is a clean and renewable energy source that can be used for power generation.Because hydropower has the advantages of low cost and no pollution,many countries around the world have built large-scale hydraulic structures to make full use of water resources.In the seismic analysis of hydraulic structures,the interaction between structure and fluid system is very prominent.The deformation of the structure changes the distribution of the flow field,and the redistributed flow field will affect the deformation of the structure.This fluid-solid coupling phenomenon has received extensive attention from engineering and academia.The study of fluid-solid coupling vibration mechanism of hydraulic structures has very important engineering significance for preventing building vibration damage accidents and ensuring the normal operation of buildings.In the study of fluid-solid coupling of hydraulic structures,the calculation of flow field in infinite domain is often involved,and the calculation of infinite domain using finite element method will generate huge computational overhead.How to consider the influence of the infinite domain flow field on the structure and establish a structural vibration equivalent model considering the coupling effect of the medium is still the focus of scholars at home and abroad.This paper studies the structural equivalent vibration model of dam-storage system based on semi-analytical semi-numeric method.Under the assumption that the fluid is incompressible,the dynamic effect of the medium on the structure is equivalent to the effect of the additional mass of the fluid.Based on the infinite element theory,the infinite watershed in the two-dimensional case is analyzed in the infinite direction and dispersed in the depth direction.Achieve simplification of additional quality calculations.An additional mass calculation program based on infinite element is written on the MATLAB software platform.The calculation of the additional mass model is realized by the finite element numerical simulation software ADINA,and a structural equivalent vibration model considering the fluid-solid coupling effect is constructed.The self-vibration characteristics and seismic response of the fluid-structure coupled system are analyzed by comparison with the dam-storage system under direct fluid-solid coupling simulation.The main research contents of this subject are as follows:1)Under the premise of consulting a large number of domestic and foreign literatures,the research methods and research contents of the fluid-solid coupling of the dam reservoir system are briefly summarized,and the shortcomings of the existing simplified models are analyzed;2)based on limited The meta-analog software ADINA describes the fluid-solid coupling simulation technology,and simulates the typical dam system in two-dimensional case to verify the correctness of the numerical simulation method.3)It is assumed that the reservoir water is an ideal fluid without spin and no viscosity.The Galerkin method is used to derive the finite element equations of the fluid-solid coupling of the dam reservoir system,and the decoupling of the coupling equation is realized under the premise of ignoring the fluid compressibility,so as to obtain the calculation formula of the fluid additional mass;4)based on infinity Meta-method,using MATLAB to write the program to calculate the fluid stiffness matrix;5)using ADINA software to numerically simulate the additional mass model,and compare it with the modal analysis and seismic response results under the fluid-solid coupling model,so as to compare the equivalent vibration model to evaluate.