Methods for modelling the ultimate strength of orthotropic plate with a central hole under uniaxial tension

The stress state in plates with circular holes made of orthotropic homogeneous material has no singularities and it can be exactly determined. The numerical stress distribution calculation by the finite element method will be compared with those obtained by the analytical equations developed by several authors. The goal of this work is to validate the finite element method, in conjunction with in-plane and out of plane failure criteria, in order to calculate not only the stress distribution for orthotropic plates with circular holes but also to determine their ultimate strength. The tool used has been a user subroutine (UMAT) specially developed for this work that implements the features of the commercial FE program (ABAQUS). The code performs an implicit analysis of the stress-state with progressive damage modelling. Finally, both of them, numerical and analytical method, will be checked with experimental tests by means of strain gauges. C 2006 Springer Science + Business Media, Inc.