The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigati...The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results.展开更多
The Lundberg–Palmgren(L–P)fatigue life formula,as a statistical fatigue theory,has been widely used in the industry.However,its direct applicability is limited to the components treated by surface strengthening tech...The Lundberg–Palmgren(L–P)fatigue life formula,as a statistical fatigue theory,has been widely used in the industry.However,its direct applicability is limited to the components treated by surface strengthening technologies.Rolling contact fatigue tests and surface integrity measurements of American Iron and Steel Institute(AISI)9310 rollers with several surface treatments were performed to address this issue.Based on these results,a modified L–P fatigue model was proposed,enabling the consideration of surface modification including surface roughness,residual stress,and hardening introduced by different surface treatments.Compared with the original L–P fatigue formula,its results are more accurate for surface strengthened specimens.Furthermore,this method can assess the contact fatigue life of gears treated by surface strengthening techniques.展开更多
基金Project(51108355)supported by the National Natural Science Foundation of ChinaProject(2011CDB269)supported by the Natural Science Foundation of Hubei Province,China
文摘The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results.
基金supported the National Natural Science Foundation of China(No.52275050)Shaanxi Key Laboratory of Gear Transmission Open Program(No.SKLGT-2022-005).
文摘The Lundberg–Palmgren(L–P)fatigue life formula,as a statistical fatigue theory,has been widely used in the industry.However,its direct applicability is limited to the components treated by surface strengthening technologies.Rolling contact fatigue tests and surface integrity measurements of American Iron and Steel Institute(AISI)9310 rollers with several surface treatments were performed to address this issue.Based on these results,a modified L–P fatigue model was proposed,enabling the consideration of surface modification including surface roughness,residual stress,and hardening introduced by different surface treatments.Compared with the original L–P fatigue formula,its results are more accurate for surface strengthened specimens.Furthermore,this method can assess the contact fatigue life of gears treated by surface strengthening techniques.
