Mechanical Properties Of Aluminum Foam Filled Steel Tube And Its Application In Hydraulic Gates

As the scale of water conservancy and hydro-power projects expand continuously,the size of the associated hydraulic steel gates is also growing.Due to the constraints of the capacity of the hoist,the weight of the hydraulic steel gate should not be too large.Therefore,the design of modern hydraulic steel gates adopts lightweight design scheme to reduce the weight of the gate and improve the flexibility of the gate's opening and closing.However,light-weighting can also have some negative effects,such as reducing the stability of gate arm and generating flow-induced vibration.Aluminum foam filled steel tube is a good way to solve this problem.While the aluminum foam material itself is not strong in carrying capacity,it has a long stress platform and therefore can be continuously deformed under external load.Filling the aluminum foam material into the thin-walled steel tube can complement the advantages of these two materials,improve the stability of the thin-walled steel pipe,and bring their mechanical properties into full play.Therefore,filling the aluminum foam material into the arm of the hydraulic arc steel gate is an important way to solve the problem of light weight of the gate.This article mainly does the following work:(1)The mesoscopic finite element model of foamed aluminum was established by stochastic simulation.The model was used to simulate the quasi-static compression process,and the mechanism of crushing deformation of aluminum foam was explored.At the same time,the results of numerical simulation were processed,and the stress-strain curves of aluminum foam materials were obtained.Based on the stress-strain curve,the constitutive relation of foamed aluminum materials with different densities was established.(2)From the Euler's formula of the critical load of the slender bar,the length-width ratio and the width-thickness ratio are two variables that affect the thin-walled steel pipe.The finite element models of slender and intermediate thin-walled square steel tubes were established respectively.The finite element model of the corresponding foam-filled aluminum-filled steel tubes was established.The static analysis and eigenvalue buckling analysis of the model were carried out to explore the foam aluminum filling.The effect on the stability of thin-walled steel tubes and the effect of length-width ratio,width-thickness ratio,and foam aluminum's density;(3)The finite element model of the hydraulic arc steel gate was established.The foamed aluminum material was filled into the arm of the gate.The static analysis and eigenvalue buckling analysis of the model were carried out.The results of numerical simulation were used to explore the aluminum foam.The effect of filling on the strength,stiffness and stability of hydraulic arc steel gates is verified by the feasibility of the method of filling the foam aluminum with arms.The research in this paper shows that: Firstly,from a microscopic point of view,the crushing failure of aluminum foam material first occurs at a position where the pore-to-pore spacing is too small,and the crushing of local pores will have a chain reaction,then form a crush belt in the material.The crushing belt expand outward and eventually cause the whole material to be destroyed.Secondly,the mesoscopic finite element model of the foamed aluminum material can be conveniently and quickly established by a random simulation method,and the parameters such as porosity and pore distribution can be easily adjusted.The simulation of the real situation is good and it is easy to optimize the design.Third,after the foam aluminum is filled into the steel tube,the aluminum foam can effectively inhibit the lateral direction of the thin-walled steel tube,prevent local buckling of the pipe wall,and improve the elastic stability performance of the thin-walled steel tube.Finally,filling the foam aluminum into the support arm of the hydraulic steel gate can increase the static strength of about 15%,and significantly reduce the deformation of the gate.At the same time,the local buckling position of the steel gate can be transferred from the less stable supporting arm to the main girder with better stability by foam aluminum filling to improve the overall stability of the steel gate.