Dynamic Mechanical Performance Analysis Of Miter Gates Under Complex Loads

In recent years,with the rapid development of the national economy,the throughput of ship locks has increased rapidly.Its task is to retain water and control the navigation openings of the ship lock,ensuring the safe passage of ships through the lock.The miter gate is one of the important components of the ship lock.As the miter gate works under atmospheric conditions,some of the gate bodies are underwater,and the gate leaves are corroded;Especially when the gate operates under low speed and heavy load conditions,the door body is subjected to wind loads,water resistance,swells,and other actions,coupled with frequent opening and closing for a long time,leading to cracks on the door body due to fatigue damage,resulting in potential safety hazards.Therefore,regular maintenance of the miter gate is very important.However,this not only consumes a lot of manpower and material resources,but also prolongs the maintenance period.During the maintenance period,it also brings huge safety hazards and social instability,and leads to the suspension of navigation or low navigation efficiency of the ship lock,resulting in huge losses in social and economic benefits.The fatigue damage and friction and wear of the bottom pivot of the miter gate are closely related to the bearing capacity of the gate body.However,existing theoretical formulas are difficult to obtain all the stress conditions of the gate under dynamic loads.Therefore,in this paper,the Gezhouba 2 # gate is taken as the research object,and the fluid domain and air-water three-dimensional models of the gate are constructed respectively.The dynamic numerical analysis of the gate is performed using Fluent and fluid-solid coupling(FSI)methods.The resistance,flow field distribution,and stress conditions of the gate during dynamic operation are obtained.Then,the vibration signals of the gate are extracted and compared with the measured data to determine the accuracy of the simulation.The main conclusions obtained are as follows:1)In this paper,a fluid-structure interaction model for Fluent fluid domain and gate flow field were established based on modal analysis and mesh generation for Gezhouba No.2gate,and the main parameters and setting methods of the gate are given.The resistance of the gate operation,the pressure and velocity in the fluid domain,and the stress of the gate body were calculated.This simulation analysis provides a theoretical basis for simulating the dynamic model of the gate and addressing issues such as gate vibration,fatigue,maintenance,and signal processing.2)The dynamic force of miter gate was analyzed,and the force law of gate opening and closing was studied.The simulation results were obtained.By comparing the theoretical formula calculation value and simulation results,it was founded that the average dynamic force of the gate is about half of the theoretical calculation value,but the maximum force is about twice the theoretical calculation result.In order to ensure the safety and reliability of the gate,its design load should be twice the theoretical calculation value.3)The resistance of the gate operation was calculated using a rigid gate body and a flexible gate body,and the data results were analyzed.The results show that the resistance of the flexible door body is more complex and has a larger amplitude.Finally,the accuracy of the simulation is confirmed by comparing the simulation data with the measured data.4)The operating conditions and forces of the miter gate,as well as the impact of wind load and water resistance on the gate are analyzed.The stress conditions of the miter gate under different working conditions(wind speed,water depth,opening speed)were calculated,and the relevant specific values were calculated and the variation rules of its resistance were summarized.5)After analyzing the stress changes and data of the door body,it is believed that the maximum stress on the door body is located above the gas-liquid interface of the door shaft.6)The process of water injection and discharge in the river channel was simulated,and the pressure and velocity changes in the fluid domain were calculated.The maximum hydrostatic load of the gate is obtained,with the maximum stress located below the gate shaft column.