A damage identification procedure based on Hilbert transform: Experimental validation

Abstract

This paper aims at validating the feasibility of an identification procedure, based on the use of the Hilbert transform, by means of experimental tests for shear-type multi-degree-of-freedom systems. Particularly, a three-degree-of-freedom frame will be studied either numerically or experimentally by means of a laboratory scale model built at the laboratory of the Structural, Aerospace and Geotechnical Engineering Department (DISAG) of University of Palermo. Several damage scenarios have been considered to prove the effectiveness of the procedure. Moreover, the experimental tests have been conducted by considering two different input loads: pulse forces, simulated by means of an instrumental hammer, and wide band noise base inputs, by a shake table.In the first section the damage identification procedure, proposed in recent works, is presented. The procedure is based on the minimization of an objective function mathematically based on the properties of the analytical signal and the Hilbert transform. Second section reports the experimental model geometrical data and the data acquisition set-up as built in the DISAG laboratory. In Section 3, the results of the experimental campaigns are presented and discussed having considered three damage scenarios. The validated procedure has been proved to be able to not only detect damage even at early stage but it also needs processing of only few samples of the structural response.

An Innovative Structural Dynamic Identification Procedure Combining Time Domain OMA Technique and GA

“…The Analytical Signal Method (ASM) is a recently introduced hybrid method [17] that uses the mono-component correlation functions obtained from the Inverse Fourier Transform (IFT) of the filtered PSDs. Since the Analytical Signal (AS) is very sensible to the minimum change of the natural frequencies [48][49][50], it is used in ASM to better identify them. Precisely, the AS of the mono-component correlation functions is decomposed in envelope and phase, from which it is possible to estimate the damping ratios and the natural frequencies.…”

Characterization of non-linear bearings using the Hilbert–Huang transform

“…Once the signal is filtered from noise, the HT has been shown to be capable of extracting phases and IFs for damage identification of linear scenarios. 39,40 Similarly, sections 'Characterization of non-linear SDOF bearing model using the HHT' and 'Identification of changes in the bearing behaviour using the HHT' have demonstrated that the HHT is a valid tool to characterize instantaneous changes using the response of a non-linear SDOF bearing system where noise is non-existing or has been safely removed. However, traditional filtering methods may not be as reliable in separating mixed noise and harmonics in non-linear systems, and section 'Influence of noise on the performance of the HHT' has shown that the direct application of EMD and the HT to a corrupted signal can produce misleading results.…”

Damage identification of beam-like structures with contiguous and distributed damage

“…Lacono et al . described a damage identification scheme based on Hilbert transform and demonstrated this for a shear building. Kouchmeshky et al .…”