Research On The Structure Of Brazing Periodical Sandwich Plates Of Aluminum Alloy

Periodical sandwich plates of aluminum alloys are widely used in aerospace,railway vehicles,ships,automobiles,construction and other fields,because of their series of advantages:light weight,high specific strength,high specific stiffness,good stability,thermal insulation and so on.At present,the adhesive bonding is main method of the connection between the surface and the core for the periodical sandwich plates,which results in bad thermal stability.In order to solve this problem,the brazing is used to bond between the surface and the core for the periodical sandwich plates and the pyramid lattice and honeycomb sandwich plates are manufactured by the brazing in this study.In this paper,6061 aluminum alloy is used as the base material and the effects of the structure and relative density of the pyramid lattice and honeycomb sandwich plates on the mechanical properties are studied by the combined method of theory,experiment and simulation.Furthermore,the mechanical properties between the sandwich plates with two structure are compared.It is found from the results that:When the pyramid lattice sandwich plates are carried out under the compression,the specific strength and elastic modulus increase with increasing the relative density and inclination of core rod;Under the shearing,the specific strength increases firstly and then decreases with increasing the relative density and inclination of core rod,and the specific shear modulus increases with increasing the relative density and increases firstly and then decreases with increasing the inclination of core rod;Under the three-points bending,the specific bending modulus increases with increasing the thickness of the surface sheet;Under the lateral compression and tensile,the specific strength increases with increasing the thickness of the surface sheet;In this study,the pyramid lattice sandwich plate with the inclination of 60°,the thickness of 2mm and the relative density of 9.29%has the best compression properties and one with the inclination of 45°,the thickness of 2mm and the relative density of 9.06%has the best shearing and bending properties.When the honeycomb sandwich plates are carried out under the compression,the specific strength increases with increasing the relative density and wall thickness,and the elastic modulus does the opposite;Under the shearing,the specific strength and elastic modulus increase firstly and then decreases with increasing the relative density and wall thickness;Under the three-points bending,the specific bending modulus increases firstly and then decreases with increasing the thickness of the surface sheet;Under the lateral compression and tensile,the specific strength increases with increasing the thickness of the surface sheet;In this study,the honeycomb sandwich with plate the wall thickness of 0.12mm,the side length of 3.6mm and the relative density of 5.20%has the best compression and shearing properties and one with the surface sheet thickness of 0.75mm,and the relative density of 17.37%has the best three-points bending properties.By comparison between the pyramid lattice and honeycomb sandwich plates,it is found that the mechanical properties of the pyramid lattice sandwich plates is better than the honeycomb sandwich plate when they are carried out under the compression,three-points bending,lateral compression and tensile,and it is opposite under the shearing.Based on the performance of two kinds of sandwich plate,the force of train sleeper is analyzed and rigidity check is carried out,which is found that both pyramid lattice and honeycomb sandwich plates are applied to the train sleeper.