Investigation Of Composite Structure And Mechanical Properties Of Radially Arranged Steel Sheet Reinforced Composite GFRP Bars

GFRP reinforcement is believed to be able to partially replace the reinforcement in concrete structures,which mainly because of its high strength and corrosion-resistant characteristics.However,the poor characteristics of modulus of elasticity and ductility of GFRP bars severely restrict its application in the structure.In order to solve this problem,the radially arranged steel sheet reinforced composite GFRP bar(RSGB composite bar)was developed,and its tectonic theory,molding and mechanical properties were studied in this thesis.Firstly,the interfacial characteristics and the bonding mechanism of fiber-reinforced composites material were studied in this thesis;And it made a brief analysis of steel core FRP reinforced interface stress transmission mode,based on the shear lag theory.The results shows that the greater the difference between the elastic modulus of steel core and GFRP,the higher the stress level of the interface.In order to achieve coordination of the deformation of the two materials,it needs to improve the bonding properties of both.Secondly,the structure and mechanical properties of the steel core FRP bars have been studied.It has studied on the composite materials theory of HFRP and steel core FRP;To improve the coordination between the steel core and GFRP,the idea of increasing the contact area between the steel core and the resin was adopted.In this paper the radially arranged steel sheet reinforced composite GFRP bar is first presented.Based on the structural characteristics of steel core FRP composite,the steel sheet is recommended to be used in the radial direction to ensure that the steel core is in a straight and force balance.The forming process of composite bar is introduced by combining the pulling extrusion process and special mould,and the RSGB composite bar was successfully prepared.Thirdly,using the finite element software analysis the mechanical properties of tensile of steel core GFRP without considering slippage.Results showed that the modulus and ductility of steel core GFRP bars can be improved in the tensile process;the stress state of GFRP which contacts with steel sheet is better.The steel core can increase the overall interface shear capacity,at the same time,the outer edge of the steel sheet will have larger shear stress concentration in the anchoring transition zone,tensile test shows that the effect of stress concentration on the tensile properties of the material is not obvious.Finally,the tensile,transverse shear and compression tests were carried out on the RSGB composite bars,test results shows that,the forming effect of RSGB composite bar is good,the stress-strain curve is nonlinear with ductility,the initial modulus of RSGB will be enhanced with steel core content increased;the tensile test data are in good accordance with the numerical results,which indicate that the bonding property between the steel sheet and GFRP is good;The transverse shear strength of RSGB composite bar is improved with the increase of the steel core content;The compressive strength of is decreased due to the uncoordinated deformation of the steel core and fiber,but with steel core content of ascension has increased.