A novel time domain-based multiple breathing crack diagnosis technique using Quadratic-Teager Kaiser Energy (Q-TKE)

Abstract

This paper presents a generalized time domain-based multiple breathing crack localization technique in beams with an unknown number of cracks based on Quadratic-Teager Kaiser Energy (Q-TKE) using vibration data. Localization of multiple breathing cracks is a highly challenging inverse problem, as all these breathing cracks (more than two) might be in a similar state (either opening or closing state) at any particular time instant or in contrasting states (while some breathing cracks are opening, others are in closing state) during vibration. The level of nonlinearity of vibration response is strongly dependent not only on each crack size and location but also on the application of driving force along the cracked beam. The concept of varied input frequency excitation sources is employed in the present work for multiple breathing crack identification over the tedious traditional approach of varying input force application positions. The major advantage of using Q-TKE in the present work is that it can reliably isolate and extract the very low-amplitude nonlinear sensitive components (superharmonics and intermodulation) being buried in the total response and enhance them in the time domain signal itself. Investigations have been carried out by varying the number, spatial locations, and also intensities of the breathing cracks. Sensitivities associated with measurement noise and also with limited sensors is also investigated. The results of both numerical and experimental investigations carried out in this paper concluded that the proposed Q-TKE can effectively localize closely spaced or sparsely spaced (i.e., spatially far apart) multiple cracks in the beam. The proposed Q-TKE approach is data-driven, works with limited sensors, and does not need reference healthy state measurements.