Some Studies Verify the Applicability of the Free Vibration Method of Crack Detection in Composite Beams for Different Crack Geometries

Abstract

Defect detection and classification are important issues as they cause structures to catastrophic failure. Many flaws have already been addressed, but non-destructive testing techniques for composite materials have been widely used. However, the impact of arbitrary and unpredictable flaw geometry on these approaches' applicability has yet to be observed. This paper considers the cases of a previously published article, i.e., pultrusion-produced orthotropic (GFRP) cracked cantilever beam, to determine the crack location and depth. In contrast to the well-known V-shaped crack, a new fracture model (a combination of rectangular and V-shaped) is presented due to its practical importance. Using ANSYS software, FEA simulations were carried out on the new and V-shaped crack models for the natural frequencies. The maximum percentage error for the natural frequency between new and V-shaped crack models for the same configurations was only up to 1.815. Then, the ANN model was trained using the natural frequencies dataset of V-shaped cracked cases only. Afterward, the ANN model was used for predicting the crack locations and crack depths in beams, i.e., V-shaped cracked beams and a combination of rectangular and V-shaped (new crack model) cracked beams. The ANN model gave good results for predicting the crack locations and depths in composite cantilever beams irrespective of the crack geometries. Hence, it is clear that even though the ANN model was trained using the dataset of V-shaped cracked cases, it accurately predicts the crack locations and depth in the beams, which have had new geometry.