Study on flexural fatigue test and life prediction of damaged steel beams strengthened by CFRP-OFBG plate
In order to study the fatigue properties of steel beams strengthened by carbon fiber reinforced plastics(CFRP),the self-developed smart carbon fiber reinforced plastics-optical fiber bragg gratings plate(CFRP-OFBG plate)plate with self-monitoring performance was adoptd to strengthen the damaged steel beams.Based on the completion of the four-point bending fatigue test under constant amplitude load,the fatigue properties of steel beams strengthened by CFRP-OFBG plate under different stress amplitudes were studied.The"three-dimensional solid"finite element model was established by using the finite element method,and the stress intensity factor at the crack tip of the reinforced steel beam was solved by the J integral calculation method.The fatigue crack propagation model was established based on the linear elastic fracture mechanics theory,and the fatigue crack propagation life of the steel beam strengthened by CFRP-OFBG plate was predicted.The results show that the reinforcement effect of CFRP-OFBG plate can effectively improve the fatigue life of the damaged steel beam,delay the crack growth rate,improve the stress state at the crack tip,and reduce the stress intensity factor at the crack tip.Under cyclic loading,the fatigue life of specimens strengthened by CFRP-OFBG plates decreases with the increase of stress amplitude.Comparing the test results with the predicted results,it was found that the predicted values of fatigue life of the reinforced specimens were slightly higher than the test values,which was analyzed to be mainly due to the fact that the local peeling of the CFRP-OFBG plate in the tests was not taken into account in the finite element simulations.
万方数据
维普
