Experimental and finite element analysis of a damaged API5L X52 pipeline with longitudinal crack repaired by adhesively bonded metallic patch

摘要

An alternative of repairment by means of Lord DC-80 adhesive and metallic patch on two API5L-X52 pipes steel with 10 mm in thickness, 122 mm outside diameter and 750 mm length, which were damaged by mechanically longitudinal crack with 5 mm depth is presented. Repaired pipes were submitted to pressure testing (0.68-9.8 MPa) and 3D-FEM was used to calculate the Von Mises stress and strain. Results indicated that measured strain was smaller than the allowed strain, then no yielding occurred. Pressure tests revealed that leakage occurred at 9.8 MPa, where seals failed but not the pipe or repaired assembly. FEM results showed that the adhesive served to join the steel patch and pipeline, which operated as a component that lead to lower stresses regarding to the internal pressure in pipeline. The Von Mises stress values increased with the increment of pressure resulting that for 9.8 MPa, the greatest stress was reached at both edges of the API-X52 piping, followed by metallic patch and finally, the adhesive with the lowest values. Cracked pipelines within the analyzed dimension sizes did not present integrity problems and it did not fail. This kind of repairment could be safely used for pipes that present external defects.