Numerical tool for the analysis of CTOD curves obtained by DIC or FEM

Abstract

Typically, the Crack Tip Opening Displacement (CTOD) is used only to quantify the crack closure phenomenon. However, more information about crack tip phenomena can be extracted from the CTOD curves, which can be used for a better understanding of fatigue crack growth. The main objective here is the development of a numerical tool for the automatic analysis of CTOD plots, which can be obtained either numerically using the Finite Element Method (FEM) or experimentally using Digital Image Correlation (DIC). The parameters extracted are the elastic and plastic CTOD in loading and unloading regimes, the corresponding load ranges, the crack opening and closure levels and the dissipated energy. This tool is expected to promote a fast and efficient analysis of DIC and FEM results, facilitating the implementation of CTOD analysis in the fatigue community.

Evaluation of small‐scale yielding boundary using digital image correlation results

“…This permits a jump to a new level of understanding of FCG. In previous work of the authors, 18 the elastic and total crack tip opening displacement (CTOD) ranges, Δ δ e and Δ δ p , respectively, predicted numerically at a small distance behind crack tip (8 μm), were used to define a new parameter: Figure 1 is a schematic representation of a CTOD curve, showing the elastic and plastic CTOD ranges 19 . The total CTOD, Δ δ t , is the sum of elastic and plastic components.…”