The Research On Damage Behaviour Of CFRP Strengthed RC Beam Based On Fundamental Frequency

According to the statistically analyzing on the dynamic behavior of reinforced concrete beam and strengthen beam with CFRP at domestic and abroad. Contrast to the experimental results, the finite element analysis and simulation have been carried out to study the relation of frequency and damage degree ,damage location of the beam.The details are as following:(1) According to test component, build the finite element model, at undamaged situation, finite element analysis have been done for the frequency of concrete beam and reinforced concrete beam and CFRP strengthened reinforced concrete beam .A comparison is made between the experimental results and simulation results, proved the accuracy of the finite element model.(2) Finite element method is made to calculate the cracking load of reinforced concrete beam and CFRP strengthened beam, and take this load as breadth value, make a dynamic harmonic analysis of the CFRP strengthened reinforced concrete beam to research the relationship between the cracking load and structural frequency. At the same time, study the structural frequency variation of the beam between first crack situation and no damage situation.(3)Research the relationship between the damage degree and frequency of the CFRP strengthened concrete beam at the different load situation, and make a comparison with the test solution, on the basis of these, conclude the fundamental formula which can solve the bend vibration frequency, bring forward a structure damage identify method based on dynamic test data.(4)Set up 84 models of damaged beams by the finite element program ANSYS, including 42 CFRP strengthened beams and 42 without strengthening beams, the gap simulate damage, through change the height and location of the gap to simulate damage degree and damage location of the reinforced concrete beam. Based on the solution of ANSYS modal analysis, systematically research the relationship between the structural damage location and damage degree with the frequency of the modal beam.(5)Finally, expatiated the main conclusion of the theoretic analysis and test study and finite element simulation. Bring forward the research expectation for structural damage detection and CFRP strengthening.