Study On Dynamic Water Pressure On Emersed Steel Gate Under Eathquake

Considering the fluid-structure interaction has become a hot issue in the analysis ofseismic response of the underwater structure. There will be added stresses in structure duringan earthquake, and the influence of hydrodynamic pressure is found to be neither excessivelylarge nor negligible. It is very complex that the mechanism of fluid-gate structureinteraction,which has not formed a mature domestic and standardized achievements. Thus, itis necessary to in-depth study the influnce of elastic deformation on hydrodynamic pressureof the emersed steel gate. Formulas of seismic hydrodynamic pressure are derived for theplane mass-spring system and the radical mass-spring system. The paper studied on seismichydrodynamic pressure of plate gate and radical gate by using finite element simulatingsoftware ADINA. The main tasks and results of this paper are as following:(1) The models of the plane mass-spring system and the radical mass-spring system wereestablished. Formulas of seismic hydrodynamic pressure, acting on the elastic gate (plane gateand radial gate), are derived for the models. Then the mathematical model of fluid motion wasestablished, with the boundary of gates movement. Results show that the seismichydrodynamic pressure changed with time as simple harmonic curve; the hydrodynamicpressure enlarged with the stiffness of gates: when the stiffness is small, the hydrodynamicpressure increased considerably; when the stiffness of gate is more than6106N/m, thehydrodynamic pressure value increased slowly.(2) Based on ADINA-FSI features, the simple plane gate and fluid models wereestablished, to study the influence on seismic hydrodynamic pressure. The results show thatwhen the gate is rigid, the calculated value of hydrodynamic pressure is much larger; themaximum hydrodynamic pressure value enlarged with the increase of the stiffness of gate;The position of maximum amplitude of hydrodynamic pressure distribution on the plane gateis not at the bottom of the gate, but5/6away from the top of gate.In comparison with the theoretical value of Westergaard added mass formula, the ratio,p max p westergaard, is4~5.(3) Based on ADINA-FSI features, the simple radical gate and fluid models wereestablished, to study the influence on seismic hydrodynamic pressure. The results show that the maximum hydrodynamic pressure value enlarged with the increase of the stiffness of gate;When the stiffness is large, with the order of magnitude higher107, the position of maximumamplitude of hydrodynamic pressure distribution on the plane gate is at the gate bottom, thesame as the theoretical value of Westergaard added mass formula. While, the stiffness ofradical gate is small, the position of maximum amplitude of hydrodynamic pressuredistribution on the plane gate is not at the bottom of the gate, but5/6away from the top ofgate.In comparison with the theoretical value of Westergaard added mass formula, the ratio,p max p westergaard, is4~5.