Stress Intensity Factor vs. Transversal Deflection - How to Determine the Damage Severity?

This article compare two methods to determine the severity of a damage occurring in cantilever; the first method is well-known in the literature and base on an approach from fracture mechanics, while the second is contrived by the authors and base on the transversal deflection under small loads. First, this article demonstrate the relation existing between the stiffness reduction due to damage (ie the value of the transversal deflection) and the change of the natural frequencies, exemplified for three shapes of the transversal cross-section. It is proofed that the relation is valid for all three cases, square, hexagon and circle, the damage depth being accurate determined. Afterwards, the results are compared with that provided by numerous researchers, which used the fracture mechanics approach; a good concordance can be found, with the mention that the method developed by the authors is more accurate. This is justified by the fact that their method does not introduce empirical relations, being based on the formulized physical phenomena alone.