Study On The Static And Dynamic Characteristics Of Diagonal Hydraulic Steel Dam Gate

As a control facility for the discharge of the hydraulic structures,the steel gate plays an important role in water conservancy projects.Among them,the diagonal hydraulic steel gate has a relatively small bottom shaft size,stable support,and no intermediate pier structure behind the gate.Therefore,with the advantages of strong flooding capacity,saving civil construction cost and etc.,it has broad application prospects in urban landscape gates.The type of gate has not been used for a long time,and its structural calculation and corresponding working characteristics are still unclear.Therefore,it is of great significance to analyze the structural static and dynamic characteristics of the diagonal hydraulic steel gate.In this paper,based on thin plate finite element theory,coupled vibration theory and additional mass algorithm,the static and dynamic characteristics of one diagonal hydraulic steel dam gate are analyzed and studied by using three-dimensional finite element method.The main research are as follows.(1)Based on the method of structural mechanics,the stress characteristics of the steel dam gate in equilibrium and the calculation formulas of external stress and stress arm are analyzed.According to the different operation states of the gate,the reference formulas for calculating the discharge capacity of the steel dam gate under different working conditions are selected.(2)The basic theory applicable to the analysis of gate finite element calculation is studied,including:the basic assumptions followed by the thin plate theory in static mechanics and the corresponding displacement,load function and determination of stiffness matrix;the equation of motion involved in the dry mode in dynamic modal calculations,the coupled vibration equation followed in fluid-structure interaction and the calculation principle of simplified additional mass method.It lays the foundation for the establishment and solution of the subsequent finite element model.(3)3-D FEM is used to calculate the static characteristics of the diagonal hydraulic steel gate.Then the stress and displacement sensitivity analysis of the gate components to the head height is analyzed,and the overload safety of the gate is determined by increasing head height as loading mode.On the basis of the same overload safety degree,the measures to improve the stress at the connection plate are put forward.The stress influence curve of the main component size of the gate is drawn by single factor analysis method,and the optimal design of the gate is carried out from the angle of minimum total steel consumption.The results show that the original structure layout and size design of the gate are reasonable and meet the requirements of the standard operation.The overload safety determined by the head height is 1.35.Under the same overload safety,the light weight design of the gate still meets the static requirements.(4)The modal analysis method is used to study the vibration characteristics and influencing factors of the gate under the condition of water and no water.The fluid-solid coupling vibration characteristics of the steel dam gate under the two methods of fluid modeling and simplified additional mass method are compared.The results show that the original size of the gate meets the requirements of dynamic safety.With the decrease of the water-retaining angle of the steel dam gate,the natural vibration frequency of the gate increases,and the fluid-solid coupling effect has a significant impact on the vibration characteristics of the gate.The influence of the fluid-solid effect obtained by the simplified additional mass method and the fluid modeling method on the natural vibration characteristics of the gate is consistent,and the relative error of the two increases with the increase of the water head.With the increase of water head and decreases of the water retaining angle,the effect of fluid-structure interaction on the vibration characteristics of the gate increases.The optimized gate size still meets the dynamic safety requirements.In this paper,the static and dynamic characteristics of diagonal hydraulic steel dam gate are studied,and the dimensions of steel dam gate are optimized.Therefore,the research methods and conclusions of this paper verify the rationality of the structural layout of diagonal hydraulic steel dam gate,and put forward some suggestions to improve the design of stress and component size.It also provides a reference for the structural design and operation management of similar steel dam gate,which has important engineering significance and application value.