Fatigue shape analysis for internal surface flaw in a pressurized hollow cylinder

Fatigue crack shape is simulated through a theoretical model for part-throu gh cracks in a hollow cylinder under cyclic pressure. The defect is assumed to have an elliptical-are shape. The propagation path of the surface flaw is obtained as a diagram of aspect ratio epsilon against relative depth b/t . The numerical procedure calculates the local growth increments at a set o f points defining a crack front by employing a fracture damage zone size mo del, that can directly predict the shape development of propagating cracks. The aspect ratio changes during crack growth are obtained and compared wit h the limited experimental data found in the literature. Thick- and thin-wa lled cylinders, and also semielliptical internal surface flaws are consider ed. The influence of the elasto-plastic characteristics of the steels' diff erent properties, related to test temperature, on the aspect ratio variatio n is studied. (C) 2000 Elsevier Science Ltd. All rights reserved.