Numerical assessment of stress intensity factors at tips of multi-site cracks in unstiffened panel

Abstract

The aim of this paper is to establish and demonstrate diverse capacity and performances of different numerical methods for calculating stress intensity factors' (SIFs) histories versus crack length for problems involving multiple, interacting cracks resulting from multiple site damage (MSD). A typical aero structural configuration is analysed: unstiffened flat panel made of aluminium Al 2024-T3, containing 11 holes, each of which is a site for crack growth. Analysed model makes a complex configuration with 22 cracks, propagating at the same time. The computations are carried out in FRANC2D software which is FEM based and with superposition based approximate method. The comparison of the results has shown that obtained solutions can be used for SIF predictions with acceptable accuracy.