The Influence of Top Bent Structure on Dynamic Response of Intake Tower
The top hoist chamber of the intake tower is usually a bent structure,and damage often occurs first during earthquakes,resulting in the inability of the hydropower station to operate normally.In order to explore the influence of bent structure on the dynamic response of intake tower,a study was conducted on the dynamic response of the intake structure of a pumped storage power plant's lower reservoir.Theoretical exploration was conducted based on a simplified system with two degrees of freedom and no damping,and three-dimensional nonlinear finite element numerical simulation method was used to calculate the natural vibration characteristics,displacement,acceleration,stress,damage volume ra-tio,and energy dissipation of the intake tower under two conditions of with and without bent.The response at any time was solved by time history analysis method,the viscoelastic artificial boundary was introduced to simulate the radiation damping effect of foundation.The results show that the intake tower-bent system may produce whiplash effect and reduce the dynamic response of the intake tower during the earthquake.The bent frame at the top of the tower increases the nat-ural frequency of the intake tower by about 2.10%-3.80%,reducing the maximum relative displacement and maximum acceleration of the key points of the tower body by more than 23.94%and 22.30%,respectively.With bent frame,the tensile stress of intake tower decreases but the compressive stress increases,and the damage volume ratio,plastic dissipa-tion energy and damage dissipation energy can be reduced by more than 23.93%.The bent structure at the top of the tower can reduce the seismic dynamic response of the intake tower and has a positive impact on the seismic performance of the intake tower.
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