Design Model of Damaged Steel Pipes for Oil and Gas Industry Using Composite Materials. Part II: Modeling

Abstract

This chapter presents an experimental study of a composite material for the rehabilitation of steel pipes. The damage in pipes was simulated as hole at the middle of the pipe which was made from carbon steel with internal diameter of 83 mm, thickness 12.5 mm and length of 900 mm. Cut which was chosen was (5 × 10), (7 × 14) and (9 × 18) mm for the three pipes respectively. The composite repair was fiber glass woven roving (type E) reinforced with epoxy resin. A carbon steel bolted clamp was used to clamp the pipe around the defected rectangular to minimize the delamination effect and stop the leakage of oil during the tests of the pipes. A special rig was designed to carry out pressurized tests on the repaired pipes. It was concluded that the maximum pressure obtained was 12 MPa for the pipe with a (7 × 14) mm rectangular defect. The microscopic examination showed that matrix cracking and delamination were the dominated failure mode in the most of failed pipes. Good agreement between the experimental and mode results of the radial stress-strain curves was achieved and observed at the early stages of loading [1]. However, discrepancy was observed at high strain to failure, which could be related to other relevant phenomena such as delamination and matrix macro-cracks.