Interacting Fatigue Crack Growth Analysis with Boundary Cracklet Method

Abstract

In this study, interacting crack growth in an infinite plate is analyzed with new, fast and accurate Boundary Cracklet Method (BCM) developed by Phoenix and Yavuz. An interior crack is under consideration to watch its propagation because of cyclic loading which is very common for aerospace, naval and civil engineering structures. BCM is very useful to determine the overall stress field as well as stress intensity factors for crack tips and singular wedges at crack kinks. BCM uses integral equations expressed in terms of unknown edge dislocation distributions along crack lines. These distributions derive from an accurate representation of the crack opening displacements using power series basis terms obtained through wedge eigenvalue analysis, which leads to both polynomial and non-polynomial power series. The process is to choose terms of the series and their exponents such that the tractions on the crack faces are virtually zero compared to the far field loading. Applying the method leads to a set of linear algebraic equations to solve for the unknown weighting coefficients for the power series basis terms to make no use of numerical integrations unlike in other methods. Thats why, solution takes just a few seconds on a PC. A simple crack growth emanating from a triangular hole in an infinite plate is analyzed. The fatigue crack growth is assumed to follow Paris-Erdogan Law. The results are compared to those of other numerical methods. A parametric study is performed via graphs and tables to demonstrate the ability of BCM in analysis of fatigue crack growth.