Analysis Of Flexural Performance And Hysteretic Performance Of Hollow GFRP Pipe-Concrete-Steel Pipe Composite Beam

In the 1940 s,fiber-reinforced polymer(Fiber Reinforced Polymer,referred to as FRP)combines many advantages.It has the characteristics of strong corrosion resistance,good durability,high tensile strength,small self-weight,strong plasticity,good ability to work with concrete,and simple and convenient construction.It can show good anti-corrosion performance in wet and corrosive working environment,so it can effectively extend the service life of concrete structure.Therefore,it is widely used in engineering construction.Hollow GFRP tube-concrete-steel tube composite beam(DSTB),as a new type of combined structure,has the advantages of good corrosion resistance and seismic performance and ease of construction.However,because its theoretical research is not yet mature,the research The main focus is on experimental research.Although there is a small amount of finite element analysis,it has not yet formed a complete theory and calculation method,which limits its wide application in the field of civil engineering construction.In this paper,the DSTB composite beam is taken as the research object,and the method of combining numerical simulation and theoretical analysis is used to simulate and analyze the composite beam using the ABAQUS finite element software.The flexural performance and hysteretic performance of the DSTB composite beam were studied,and a simplified calculation formula for the bending capacity of the composite beam was proposed,and engineering design suggestions were proposed.It provides a reference for future specification development and engineering practice.The main work of this article is as follows:(1)Conducted a systematic review and comprehensive understanding of the research status of DSTB composite beams at home and abroad,which laid the foundation for the research of the subject.(2)Using the finite element software ABAQUS,establish a finite element model of the hollow GFRP pipe-concrete-steel tube composite beam.By comparing with the ultimate bearing capacity and load-displacement curve in the reference test,the correctness of the selected constitutive relationship,material unit and modeling method is verified.On this basis,the numerical simulation of 58 composite beams under different working conditions was carried out.Mainly carried out in-depth analysis of its failure form,stress and strain distribution law and internal working mechanism.According to the analysis results and the related research conclusions,a simplified calculation formula for the bending capacity of this type of DSTB composite beam is proposed.(3)Based on the concrete strength grade,steel content and hollowness of the main research parameters,a pseudo-static simulation analysis of 16 hollow GFRP tube-concrete-steel tube composite beam finite element models was carried out to obtain the load-displacement hysteresis of the specimen Curve,the influence of various parameters on the ultimate bearing capacity and skeleton curve of the DSTB composite beam under different working conditions was investigated.The research results show that the ultimate bearing capacity and skeleton curve of members increase with the increase of concrete strength grade and steel content;the ultimate bearing capacity and skeleton curve of members with hollow ratios of 0 and 0.44 are larger than those of members with hollow ratio of 0.11 Many,so this component is not suitable for use in actual engineering.