Coupled Dynamic Characteristics And Design Optimization Analysis Of The Upper Structure Of Hydropower House

With the rapid development of economy and society,the hydropower industry in China is developing vigorously,and the scale of water conservancy and hydropower projects is becoming larger and larger.As the core part of the power station,the power house of the hydropower station bears a variety of static and dynamic loads.The vibration problem of the power house is becoming more and more common and complex,so the vibration analysis,vibration prediction and vibration control of the power house are becoming more and more important.Compared with the lower part and the overall structure,the upper structure of the power house is relatively weak,and its stiffness is relatively low,which is one of the focal points in the dynamic design.In the specification of the powerhouse of hydropower station design,the vibration of the pier is focused on,while there is no recheck for the vibration of the upper structure,and the roof frame is simplified as the rigid axial force link in the model.In this paper,in view of the diversity of the upper structure type and the complexity of the connection mode,the dynamic characteristics of the integral coupling structure of the roof frame,the frame structure and the lower structure are deeply analyzed and studied.The whole model of the powerhouse is established by ANSYS,the finite element analysis software,and then the roof frame model and the coupling model of roof frame and supporting structure are established respectively.The numerical simulation and vibration characteristics of various structural forms and their connection modes are analyzed in order to accurately grasp the vibration characteristics and influence laws.The main research contents and research achievements are as follows:1.The steel roof structure of two different types of plane truss and three-dimensional four-angle-conical grid frame is established.The natural vibration characteristics of the structure and the vibration response of the whole powerhouse under the hydraulic turbine vibration load and earthquake load are analyzed.The conclusion is that the three-dimensional frame structure has improved the stiffness of the powerhouse to a certain extent relative to the truss structure.The maximum dynamic displacement and the maximum dynamic tensile stress of the powerhouse are reduced under the dynamic load.2.In view of the three-dimensional roof structure,the different connecting modes between the roof and frame structures are simulated by the three forms of the hinge support at the two ends,simple support and hinge support at each end,sliding support and hinge support at each end,respectively.The natural vibration characteristics of the three different structures and the vibration response of the whole powerhouse under the hydraulic turbine vibration load and the earthquake load are analyzed.It is concluded that the stiffness of the upper structure of the powerhouse is relatively lower when the simple support scheme is adopted,but the anti vibration performance of the whole powerhouse structure is better,and the simple support scheme is suitable.3.In order to explore the influence of the upstream and downstream frame structure on the dynamic characteristics of the powerhouse,the frame structure are respectively established as both solid walls,the columns upstream and the solid walls downstream,both columns.The natural vibration characteristics of the three different structures and the vibration response of the whole powerhouse under the hydraulic turbine vibration load and the earthquake load are analyzed.It is concluded that the use of solid walls both upstream and downstream not only improves the stiffness of the upper structure of the powerhouse,but also increases the restraint stiffness to the lower structure,thus reducing the vibration amplitude of the floor and other components.In this paper,combined with an example of a hydropower project,the vibration analysis of the different forms and different connection modes of the upper structure of the hydropower plant is carried out,and the qualitative and quantitative analysis results have been obtained,which provide valuable reference for the vibration prediction and dynamic optimization design of the powerhouse of the hydropower station.