Experimental Research On Mechanical Performance Of Stainless Steel Core Slab Based On Sandwich Plate Theory

The stainless steel core plate structure is a new type stainless steel structure,which is composed of two layers of stainless steel thin plates on the surface(hereinafter referred to as panels)and the stainless steel thin-walled round tubes(hereinafter referred to as core tube)arranged in a certain regularity sandwiched in between.This combination method makes the stainless steel core plate integrating the mechanical properties of stainless steel,hollow grid frame,and honeycomb sandwich plate,when used for the floor slab.The panel and the core tube are rigidly connected by hot-air brazing technology.This type of welding method greatly reduces the residual stress of the core plate while ensuring the reliability of the joint strength.At present,scholars have conducted research on stainless steel core slabs,but the theoretical formulas proposed are only applicable to stainless steel core slabs with specific structures and do not have wide applicability.This paper mainly studies the mechanical performance and mechanism of stainless steel core slab floor under lateral load.Based on the sandwich slab theory,the deflection and strength design formulas for stainless steel core slabs of different structures are proposed.The formula has wide applicability.The specific research work is as follows:(1)The research progress on the constitutive model of stainless steel material and its application structure,the bending performance of honeycomb sandwich panel,open-web grids structure and the theory of sandwich panel at domestic and abroad were summarized.(2)The three-point bending test of five sets of stainless steel core slab full-scale specimens of simply supported unidirectional slabs on opposite sides and the stack load test of one set of full-scale specimens of simply supported two-way slabs on the four sides of the stainless steel core slab floor were designed and carried out.The force-deformation process of the stainless steel core slab floor under vertical load was studied.The load-deflection curve of the deflection characteristic point of each specimen,the load-strain curve at the characteristic point of the structure and the deformation failure mechanism were analyzed.(3)The ABAQUS finite element models to simulate the test process were established,and the reliability of the finite element models were verified by comparing the test results with the load-deflection curve,deformation characteristics and strain distribution in the finite element calculation results.Based on the finite element results and test results,the force mechanism of the core slab floor was analyzed,and the feasibility of the sandwich slab theory and its bending stiffness calculation formula used in the stainless steel core slab floor was discussed;The calculation of the core slab shear stiffness by the finite element model was discussed.(4)The finite element model of the core slab floor with different size design parameters is established,and the influence of each size design parameter of the stainless steel core slab on its shear stiffness,bearing capacity and stress distribution is analyzed,and the law of the shear stiffness,bearing capacity and stress distribution of the stainless steel core slab with various parameters is obtained.(5)Based on the results of the force mechanism analysis and parameter analysis,the calculation formula for the shear stiffness of the stainless steel core slab floor was deduced.Based on the sandwich slab theory,the calculation formula for the deflection and strength of the stainless steel core slab floor was proposed.By comparing formula calculation results,test results and finite element calculation results,the safety and effectiveness of the design formula for deflection and strength of the stainless steel core plate were verified.