Research On Damage And Performance Of GFRP Bar Under Cyclic Loading

Glass Fiber Reinforced Polymer(GFRP)has been widely used in many fields and featured good property of mechanical and corrosion resistance.It also has a broad application prospect.However,the damage will be generated when GFRP bar suffers cyclic loading in members.Thus it will decreasing the mechanical property of structure and even crush it.It can thus be seen that researching the damage and performance of GFRP bar under cyclic loading is extremely necessary.In this paper,the damage and performance of GFRP bar under cyclic loading was researched based on the mechanism of damage.By means of reviewing and analyzing the existing classical damage theory and model of FRP,and the experiment of GFRP bars stretched under cyclic loading has been implemented to study the damage behavior.Also,the damage effect of residual stiffness and life span when GFRP bars was stretched under cyclic loading has been researched.The analysis has been carried out by combining with undamaged microstructure and the damaged microstructure which suffered different loading.Results show that microcrack caused by the local structural defect of GFRP bars will be initiated along defect during initial period.With the crack gradually extend,the stress inside bars will be redistributed.After research the surface temperature of GFRP bar stretched under cyclic loading,it will be founded that the range temperature rised up linearly related to the strain of fiber and matrix in unit area.Residual stiffness curves of test specimen suffered cyclic loading present as three parts which was separated by the time nodes lied at the 20%,80% of its lifetime.These three parts respectively show different trends,which are: stiffness rise up and fall later,stiffness falls slowly,and stiffness falls extremely fast...