An automated measurement method for the fatigue crack propagation based on decorrelated digital image correlation

Abstract

Measurements of fatigue crack propagation are crucial for fatigue tests. Nowadays, fatigue tests still necessitate experimenters to manually observe and document the propagation of fatigue cracks, a process that proves to be extremely time-consuming and labor-intensive. This study introduces a novel approach to fatigue crack measurement by employing the decorrelated digital image correlation (DIC) technique, which stands in contrast to the conventional DIC method. The proposed method utilizes decorrelation field to extract crack propagation path. The proposed method enables the automated measurement of fatigue crack parameters such as width, length, and morphology. Both numerical simulations and physical model experiments were conducted to validate the effectiveness of the proposed method. The numerical experiments demonstrate that the method achieves sub-pixel level accuracy in measuring crack width, length, and morphology. The results from physical experiment further affirm the feasibility of the method for practical application.