| Glass fiber-reinforced polymer(GFRP)is a kind of material with widely applied in the fields of aerospace,civil engineering and ocean engineering.Now,GFRP bars have attracted much attention of domestic and foreign scholars,which have advantages of light weight,high strength,corrosion resistance and low cost.However,the main disadvantages of GFRP bars are their brittleness.GFRP materials exhibit low elastic modulus and poor ductility,which adversely affects the ductility of the concrete structure.Considering the hybrid theory and economy,the problem of low modulus and ductility of FRP bars is solved by combined the advantages of fiber and steel that the GFRP can protect the steel core from corrosion,and the steel core can improve the overall stiffness of the structure.Based on the concept of the steel-GFRP composite bar,three dimensional finite element models of the steel-GFRP composite bar were established to study the static flexural performance and fatigue properties.In this paper,FEMFAT fatigue analysis software is used to study the fatigue performance of steel-GFRP tendons.Based on ABAQUS finite element analysis,the post-processing files are read and the necessary fatigue simulation parameters are set up.The fatigue of steel-GFRP tendons is analyzed completely.The damage of the structure under different fatigue loads,the distribution of fatigue lines and the distribution of dangerous points are studied.Considering the use in designing the structure,the cyclic load is set to the most likely stretching cycle and the shear cycle in the actual project.By analyzing the damage of the two kinds of cycles,it can understand the location of the dangerous point,the fatigue damage,the fatigue life and other related fatigue performance.It can provide a reference for similar optimization of the structure.Based on 12 groups finite models of ABAQUS,the structure of mechanical properties was studied respect to steel reinforced volume fraction,the steel brand and steel reinforced section form,on account of the results of finite element analysis,and further fatigue analysis of steel-GFRP reinforcement formed 30% score 8 pieces of Q235 steel of annular array was done,with the increase of tensile cyclic loading,the fatigue risk point would gradually shift outward from the steel-GFRP core center,meanwhile,the fatigue danger position of reinforcement in the longitudinal was random.The fatigue damage of notch samples under cyclic shear load concentrated on local area,internal steel would fail in the form of bending fatigue.Finally,you can get the whole structure of the fatigue life curve by the correction of fatigue notch and fatigue gap size.The simulation of steel-GFRP reinforcement showed fatigue limit value of tensile fatigue load and shear fatigue load equaled the ultimate resistance of 30% and 40% respectively.The limit fatigue value of the structure could be increased by improving the internal steel strength and steel reinforced chamfering.Finally,the low period failure mode of steel-GFRP was experimentally studied.The experimental results were in good agreement with the simulation,which proved that the failure modes were related to stress level,damage accumulation degree and number of load cycle.In conclusion,using fatigue simulation analysis method can save the high test cost of structure preliminary design and provide reference data for structure optimization design. |
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