Reinforcing Effect Research Of Pressure Pipeline Reinforced By Carbon Fiber Sheet

Pressure pipeline corrosion defects are often divided into inner corrosion and outer corrosion.General outer corrosion is divided into four categories: the whole area of uniform corrosion, local corrosion, pitting corrosion and combined corrosion. The major shapes of the defects are usually square or oval. Pressure pipelines often include along the axial, circumferential, or the axial and circumferential multiple pitting defects. Those defects have interactions as a result of being too close. Non-metallic fiber materials are gradually widely used in the structure reinforcement, but which are still in their infancy for the repair of pressure pipelines containing defects, and the evaluation of the reinforcing effect is still in the exploratory stage for lacking evaluation criteria. This paper mainly studies the reinforcing effect of carbon fiber sheets which are supposed to reinforce the pressure pipelines including two types of defects, the whole area of uniform corrosion and pitting corrosion to provide comments and suggestions for the actual reinforcement engineering of pressure pipelines.In the direction of the whole area of uniform corrosion, this paper uses both experimental and numerical simulation methods to study. First this numerical simulation uses“3D solid-contact-shell” finite element model. Then reasonable unit types are chosen after a premade. What’s more, it is also based on related parameters from the basic test. At last, these basic parameters are used in turn to improve the model to ensure the accuracy of modeling. And the results of the experiment match the numerical simulation, which further verify the validity of the modeling indirectly. In the direction of pitting corrosion, this paper uses numerical simulation method to study for the related conclusions. The results show: the reinforcing effect of carbon fiber cloths which reinforce pressure pipelines including the whole area of uniform corrosion defects appear the situation of diminishing marginal benefit. The sliding distance from middle to both ends increases gradually in the whole reinforced area. The sharper and deeper individual defect in pressure pipeline is, the greater the stress concentration factor is and the more reinforcing layers are needed. The stress concentration factor impacted by the wall thickness of pressure pipelines ismainly due to the influence of the proportion of depth of pipe wall thickness has changed. At the same time, after comparing the influence of the depth of the defect, the axial spacing and circumferential spacing on stress concentration coefficient of the pressure pipelines, the depth of the defects have the maximum impact which is followed by axial spacing. Therefore, when calculating the reinforcement for the pressure pipelines with defects, this article mainly considers the influence of the depth and the axial spacing.