Fatigue strengthening of cracked steel plates with CFRP laminates in the case of old steel material

Abstract

This paper reports an experimental study performed to investigate the effectiveness of carbon fiber reinforced polymer (CFRP) laminates in extending fatigue life of old cracked metallic structures. Specimens consist of old metallic plates, mild steel and wrought iron, with one single crack emanating from a rivet hole. This cracking configuration has never been adopted in literature studies and was chosen to be representative of real cracked elements in riveted connections. Two different initial crack lengths before reinforcement, representing two degrees of fatigue damage, were adopted. Four strengthening configurations were investigated including single-sided and double-sided strengthened specimens, Normal Modulus (NM) CFRP plates with or without pre-stressing, and Ultra High Modulus (UHM) CFRP plates. «Beach marking» technique as well as crack gauge were used to monitor and record the crack propagation during fatigue loading. Experimental results show that the application of CFRP plates can effectively reduce the crack growth rate and extend the fatigue life. CFRP plates with high modulus were found to be more efficient. This study represents a contribution to the present state of research and provides some interesting results on crack propagation in CFRP repaired elements close to real riveted ones.

Mixed mode I/II fatigue crack arrest in steel members using prestressed CFRP reinforcement

“…Furthermore, existing knowledge on the issue is more focused on CFRP-strengthening of notched steel plates/beams under the simple mode I (tensile mode) loading condition, such as uniaxial tension/bending (see for example [7][8][9][10][11][12][13][14][15][16]). However, it is quite evident that a combination of modes I and II (shear mode), hereafter referred to as the mixed mode I/II loading condition, often acts on structural members that can lead to fatigue crack initiation and propagation up to the failure of fatigue-critical structural members [17,18].…”

Stress Intensity Factor Assessment for the Reinforcement of Cracked Steel Plates Using Prestressed or Non-Prestressed Adhesively Bonded CFRP

“…Previous experimental works on cracked metallic plates made of S235 carbon steel were performed in order to investigate the effectiveness of different CFRP reinforcement configurations (see [ 26 ]).…”

“…Observation of real crack size and shape in the thickness of the specimen is then possible after complete failure of the steel plates. More details about the measurement of the crack propagation for all reinforced specimens can be found in [ 26 ]. Figure 2 shows the “beach marks” obtained for all samples (strengthened and un-strengthened ones).…”

“…In a preceding study led by the authors [ 24 , 25 , 26 ], the efficiency of different CFRP repair configurations, in order to prolong the fatigue lifetime of both mild steel and wrought iron un-symmetrical cracked steel plates, was proven. Non-pre-stressed and pre-stressed normal modulus (NM) CFRP laminates as well as ultra-high modulus (UHM) CFRP laminates were studied, with both single and double-sided repairing configurations.…”

Interfacial bond-slip relationship between Carbon Fiber Reinforced Polymer Plate and Concrete after High Temperature of Asphalt Paving Construction

“…Due to the excellent material properties of Carbon Fiber Reinforced Polymer (CFRP), this material has been widely applied in the reinforcement of bridge structures (Siddika et al, 2019;Zhuang et al, 2018;Bocciarelli et al, 2018;Lepretre et al, 2018;Chataigner et al, 2018). Many scholars have carried out many investigations on the mechanical properties and failure mode of CFRP reinforced beams (Hawileh et al, 2014;Gallego et al, 2017;Chung et al, 2018).…”