Experimental and simulation study on pipe with crack repaired by composite material

Objectives  In order to study the bearing characteristics and failure modes of the cracked pipe wrapped with fiber reinforced polymer, A three-point bending test was carried out on a cracked aluminum alloy pipe reinforced by carbon fiber reinforced polymer using epoxy resin. Methods  The repair effect was evaluated by comparing the load-displacement curves before and after repair, and the effects of crack length, repair widthand thickness on the bearing capacity and failure mode of specimens were further discussed. The three-point bending simulation model of cracked pipe repaired by CFRP was established to simulate the failure of adhesive layer and carbon fiber cloth. The numerical results are compared well with the corresponding experimental results. Results  The test and simulation results show that three-layer carbon fiber cloth can effectively inhibit the crack propagation. With the increase of the number and length of reinforcement layer, the ultimate bearing capacity of the specimen increases. The maximum bearing capacity of the specimens repaired with four-layer carbon fiber cloth has greatly exceeded the pipe without crack, but the ductility and shear bearing capacity of the pipe are reduced. For the same repair layer, the ultimate bearing capacity after repair shows a greater downward trend with the increase of the crack length. Conclusions  The research results have certain guidance and reference significance for cracked pipe reinforcement in engineering.