Three-point bending test and simulation study on pipe with crack repaired by composite material

  Objectives  In order to study the bearing characteristics and failure modes of a cracked pipe wrapped in carbon fiber-reinforced polymer (CFRP), a three-point bending test is carried out on a cracked aluminum alloy pipe strengthened with CFRP using epoxy resin.

  Methods  The reparative effects are evaluated by comparing the load-displacement curves before and after the repair, and the effects of crack length and repair width and thickness on the bearing capacity and failure mode of the samples are further discussed. A three-point bending simulation model of the cracked pipe repaired by CFRP is established to simulate the failure of the adhesive layer and carbon fiber cloth. The experimental results are compared with the simulation results.

  Results  The test and simulation results show that the use of a three-layer carbon fiber cloth can effectively inhibit crack propagation. With the increase in the number and length of reinforcement layers, the ultimate bearing capacity of the sample increases. The maximum bearing capacity of samples repaired with four-layer carbon fiber cloth greatly exceeds that of uncracked pipes, but the ductility and shear bearing capacity of the pipes are reduced. For the same repair layer, the ultimate bearing capacity after repair shows a greater downward trend with the increase in crack length.

  Conclusions  The results of this study have certain guidance and reference significance for cracked pipe reinforcement in engineering.