Numerical Study of CFRP Repairing for Oil and Gas Pipelines with Cracks
The strength decline caused by cracks is one of the main causes of accidents in underground oil and gas pipelines,and the high strength,high modulus and corrosion-resistant carbon fiber reinforced resin matrix composite(CFRP)can be well wound to repair the defective pipe segment.Aiming at the 20 steel rectangular crack defect pipeline repaired with or without CFRP,the response process of the cracked pipeline before and after repair under internal pressure load was simulated by ANSYS finite element software,and the influence of crack angle,crack length,crack dep th,repair length,repair thickness and other parameters on the strength of cracked pipeline were analyzed.The results show that the maximum Mises equivalent stress of cracked pipeline increases with the decrease of the angle between crack and pipe axis and the increase ofcrack length and depth.The increase of internal pressure load aggravates the influence degree of defect parameters on pipeline strength.In engineering,the propagation of crack in depth and length direction should be strictly controlled,and the cracked pipeline should not be maintained until internal decompression.The thickness of CFRP repair is the main factor affecting the strength of the cracked pipeline after repair.The maximum Mises equivalent stress of the cracked pipe decreases linearly as the repair thickness increases to a certain extent.
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