Repair of small damages in steel pipes with composite patches

Abstract

The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Removal of damaged pipes with new ones gives rise to major disruption during operation. This causes loss of time and cost. This study aims to prevent crack propagation and to obtain fast repair in damaged area, at the beginning of the damage. Repair of small cracks in steel pipes using composite patches has been studied in this work. The aim of the study is to repair small cracks less than 8 mm length. For this purpose, holes with 8 mm diameters were drilled in 170 mm long pipes and composite patches with 2, 2.6 and 3.2 mm thickness and 35, 40 and 45 mm overlap lengths with 60, 90 and 120° overlap angles were attached with an adhesive of 0.2 mm thickness. The repaired pipes were subjected to internal pressure until damage occurred. A finite element model was developed and the numerical results were verified based on experiments. The repair of steel pipe with adhesive bonding was successfully achieved under high pressure with composite patches.The results show that the increase in overlap angle results in an increased surface area, and consequently an increase in failure load. Furthermore, the failure load increased with an increase in patch thickness. Additionally, it is seen that the failure load does not change significantly with increasing patch thickness.