复合材料修复含裂纹圆管的三点弯曲试验及仿真研究

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

[目的]为研究裂纹管道在用纤维增强聚合物加固后的承载特性和失效模式,对用环氧树脂胶粘贴碳纤维布加固的含裂纹铝合金圆管进行三点弯曲试验。[方法]首先,比较修复前、后的载荷位移曲线并对修复效果进行评估;然后,讨论裂纹长度、碳纤维布修复宽度及厚度对构件承载力与破坏形态的影响;最后,建立碳纤维布修复裂纹管道的三点弯曲仿真模型,用以模拟胶层和碳纤维布的失效,并将试验与仿真结果进行比较。[结果]结果显示,3层碳纤维布能够有效抑制裂纹扩展,随着碳纤维布加固层数和铺层长度的增加,构件的极限承载力显著提高,4层碳纤维布修复试件的最大承载力已经大幅超过无裂纹管,但同时也会降低管道的延展性和抗剪承载能力;在相同修复层尺寸下,裂纹管道修复后的极限承载力随裂纹长度的增加快速降低。[结论]研究结果对实际工程中裂纹管道加固有一定的指导和借鉴意义。

[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 fourlayer 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.