Study On Constitutive Relation Of Square Concrete Columns Confined By CFRP Under Different Strain Rates

In recent years,due to the large-scale industrial production of carbon fiber reinforced polymer(CFRP)composite materials,the use of this high-performance material as a constraining material has received extensive attention.In a reinforced building,many buildings are subjected to dynamic loads: such as concrete structures in seismic zones,structural damage caused by bridge dynamic loads,explosions,impacts,etc.With the increase of strain rate,CFRP-constrained concrete will exhibit different mechanical properties and failure modes than static ones.In this paper,relevant experiments are designed for analysis.The current to the CFRP concrete dynamic mechanical properties and dynamic load on our constitutive relation of the study is less,in order to grasp the CFRP confined concrete stress-strain relationship,this article to building structure is simplified into a block height is 300 mm,the design of 30 CFRP block of confined concrete under different strain rate through the uniaxial compression test of different cross section aspect ratio,chamfering radius and strain rate of CFRP axial stress-strain relationship of confined concrete and the influence of CFRP cloth stress-strain relationship;The failure of the test block in the test was statistically analyzed.The experimental results show that the stress-strain curves have the same trend and similar overall shape at different strain rates.The compressive strength of confined concrete increases with the increase of chamfering radius and strain rate,and decreases with the increase of section length-width ratio.For every 10 times of increase of loading rate,the ultimate compressive strength of CFRP confined concrete increases by about 1.5% to 18%,and its deformation capacity increases.Finally by using the finite element software ANSYS to simulate the process of testing a group of test specimens,and on the basis of material test the parameters in the model,based on the stress strain curve of different parameter model,constraints,column section stress and the stress of CFRP cloth extraction have been compared with the test data,to verify the reliability of ANSYS finite element model is established in this paper.