Estimation of the limiting pressure in a pipe with an indentation

Urgent requirements for the determination of the ductile-fracture ultimate load for defects of the indentation type in pipelines are pointed out. The authors propose an idealized model of the limiting plastic state of a pipe with a longitudinally infinite indentation. To assess the influence of the finite length of the indentation, an approximate model for rectangular indentation has been developed. Practical formulas for the calculation of residual strength in the case of the absence of axial stresses have been derived and analyzed.