Study Of Repair And Reinforcement On Circular Steel Pipeline With Carbon Fiber Cloth

Oil and gas pipelines arise some local drawback damages including grooves, thinning,holes in the service frequently, which dues to mechanical collision and external load. Andthese damages can reduce the reliability and durability of the pipe. The stress concentrationhappens in the local defect area of the pipeline, and the site will leak and rupture failurewhen the stress is greater than the tensile strength of the base metal. Thus, how to repair thedamage of pipeline is an important object in the oil and gas transportation sector.Reinforcement with carbon fiber composite (CFRP) has been recognized as areinforcement method in pipeline reinforcement industry, because of its low cost of pipelinereplacement, saving time and simply process. This is due to that CFRP has high tensilestrength, high elastic modulus, thin thickness, simple operation and it can endure hightemperature. Firstly, the reinforcement test of the analog defects on the pressure pipelinewith CFRP was studied in this paper. At the same time, the mechanical properties of thepipeline before reinforcement, reinforcement layer and layers with CFRP were studied. Theresults show that the reinforcement effect is evident. The stress of the defects can reduce.And the reinforcement with two layers is more effective than one layer.Secondly, the defective pressure pipeline was numerical simulated with finite elementsoftware ANSYS and the stress distribution of the pipeline under test conditions wasanalyzed. The results show that the stress basic form and trend of the test simulate areagreement with those of numerical simulate. So that the result of numerical analysis iscredible and ANSYS is capable of simulate the test case better.Finally, the orthogonal test of the finite element model was carried out and thedifferences of the contribution of pipeline impact factors on CFRP theoretical layers wereanalyzed. The results show that the defect length is the most important factor, followed bypipe wall thickness, and the impact of the defect width and depth is smaller. Limitedmaterial can make maximum value by deploying parameters with reason.