Collapse of pipes with non-uniform corrosion defects under external pressure: A reverse inversion modeling method

Abstract

The irregularity and non-uniformity of defects is one of the important factors affecting the evaluation bearing capacity for pipes. For more accurately evaluating the anti-collapse capacity of pipes with non-uniform corrosion defects, an electrochemical accelerated corrosion system is used to simulate the corrosion process of pipes and prefabricate corrosion defects on pipes. And the corrosion resistance of different pipes’ materials is revealed also. Further, 3D laser scanning technology is used to obtain the geometric morphology and non-uniform surface features of corrosion defects. Based on the precise geometry of corrosion defects, a reverse inversion modeling method is taken to reconstruct the numerical model of corrosion defect pipes and the numerical results show correlate well with collapse experiments whether collapse modes or pressures. For the pipe with a “Slow wave” shape surface of corrosion defect, it is more accurate to calculate collapse pressure based on the defect mean depth, while the “V” shape surface is calculated based on the maximum depth.