A novel singular spectrum analysis–based baseline-free approach for fatigue-breathing crack identification

Breathing cracks are the most common type of damages that occur in structures subjected to fatigue loading. These breathing cracks induce nonlinearity in the dynamic signatures of the cracked structure which carry useful information about the damage. In this article, we present a new baseline-free algorithm using singular spectrum analysis for breathing crack detection, localization, and characterization. The major advantage of using singular spectrum analysis is that it has the ability to reliably extract the nonlinear harmonics and intermodulation components buried in the noisy components of the response of the structure with breathing crack. A new damage index based on singular spectrum analysis exploiting the nonlinear harmonics and intermodulations in the response is proposed. Numerical simulation studies are carried out to evaluate the proposed damage diagnostic algorithm and later complemented with experimental studies to demonstrate its practical application.