Three-dimensional finite element analysis of circumferentially-cracked notched and un-notched cylindrical components

Abstract

A comprehensive three-dimensional computer-aided finite element study is made in an attempt to calculate the stress intensity factor ( K I ) for a variety of V-notched and un-notched circumferentially-cracked geometries made of mild steel subjected to remote uniform bending moment, M. Throughout the study, the solid modelling facility of SDRC† (GEOMOD) was interactively utilised to create the different cracked geometries. Prior to the analysis, these geometries were transferred to the pre-processor (SUPERTAB) for model creation, mesh definition and model checking. The appropriate remote bending moment and imposed restraints were also applied interactively. In this study, the stress-intensity factor calculations for the different configurations were based upon the resulting displacement field just behind the crack tip. The effect of crack depth, notch-tip radius and included angle of the V-notched specimens upon the stress-intensity factor K I were examined. The work also included the effect of circumferentially cracked un-notched specimens upon K I and comparisons with the earlier solutions of Benthem and Koiter ( Methods of Analysis and Solutions of Crack Problems, pp. 131–178, 1973) and Harris ( J. Basic Engng. 89, 49–54, 1967) were made and the results show good agreement. The finite element study was also extended to evaluate the effect of complete and partial contacts of the cracked surfaces in the compressive side of the specimen upon the resulting stress intensity factor, K I . The current results agree with the general trends of the experimental findings observed earlier by Sawaki, Aoyama and Kawaski ( Int. J. Fracture 26, 43–54, 1984).