Instantaneous Spectral Entropy: An Application for the Online Monitoring of Multi-Storey Frame Structures

Civera, Marco; Surace, Cecilia

doi:10.3390/buildings12030310

Cited by 26 publications

(12 citation statements)

References 48 publications

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“…transform, the Stockwell transform, the CWT method, etc. 46,47 All the abovementioned methods contain a set of limitations, which makes choosing the correct transform method important. In the case of STFT, the limitation is caused by the fixed windowing function length, where fine time resolution results in a coarse frequency distribution.…”

Section: Wave Processing Methodsmentioning

confidence: 99%

A novel ultrasonic inspection method of the heat exchangers based on circumferential waves and deep neural networks

et al. 2023

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The heat exchanger (HE) is an important component of almost every energy generation system. Periodic inspection of the HEs is particularly important to keep high efficiency of the entire system. In this paper, a novel ultrasonic water immersion inspection method is presented based on circumferential wave (CW) propagation to detect defective HE. Thin patch-type piezoelectric elements with multiple resonance frequencies were adopted for the ultrasonic inspection of narrow-spaced HE in an immersion test. Water-filled HE was used to simulate defective HE because water is the most reliable indicator of the defect. The HE will leak water no matter what the defect pattern is. Furthermore, continuous wavelet transform (CWT) was used to investigate the received CW, and inverse CWT was applied to separate frequency bands corresponding to the thickness and lateral resonance modes of the piezoelectric element. Different arrangements of intact and leaky HE were tested with several pairs of thin piezoelectric patch probes in various instrumental setups. Also, direct waveforms in the water without HE were used as reference signals, to indicate instrumental gain and probe sensitivity. Moreover, all filtered CW corresponding to resonance modes together with the direct waveforms in the water were used to train the deep neural networks (DNNs). As a result, an automatic HE state classification method was obtained, and the accuracy of the applied DNN was estimated as 99.99%.

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Section: Wave Processing Methodsmentioning

confidence: 99%

A novel ultrasonic inspection method of the heat exchangers based on circumferential waves and deep neural networks

et al. 2023

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“…The above led the authors to conclude that the optimal values of gamma and beta for this particular application were γ = 3 and β = 20. The authors used the same values of beta and gamma in [63] to estimate the instantaneous spectral entropy of vibration signals for detecting sudden damage related to structural changes of civil structures and infrastructures.…”

Section: ) Fluid Dynamicsmentioning

confidence: 99%

Applications of the Generalized Morse Wavelets: A Review

et al. 2023

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The study of signals, processes, and systems has motivated the development of different representations that can be used to analyze and understand them. Classical ways of studying the behavior of signals are the time domain and frequency domain representations. For the analysis of non-stationary signals, time-frequency representations have become an essential tool to understand how the frequency content of signals changes with time. A common time-frequency technique employed in the literature is the wavelet transform. Nevertheless, selecting an adequate mother wavelet to perform the wavelet transform has become challenging due to the diverse available wavelet families. This paper reviews the applications and uses of a particular class of wavelet basis known as the Generalized Morse Wavelets. This class of wavelet family provides a systematic framework to choose and generate a wavelet for general-purpose use. This study reviews the application of Generalized Morse Wavelets in biomedical engineering, dynamical systems analysis, electrical engineering, geophysics, and communication systems. Moreover, the parameters of the Generalized Morse Wavelets used in each study are presented. The results of this study reveal that Generalized Morse Wavelets have proven helpful in studying signals, systems, and processes in areas ranging from biomedical engineering to geophysics. Nonetheless, the parameters of the Generalized Morse Wavelets are yet to be chosen through a rigorous methodology and argumentation. Therefore, there is an opportunity to generate methods for selecting the parameters of the Generalized Morse Wavelets based on the characteristics of the signals, systems, or processes under research.INDEX TERMS Generalized Morse wavelets, mother wavelet selection, continuous wavelet transform, applications, time-frequency analysis.

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“…Since the results presented for the numerical case demonstrate that the LF can be a feasible alternative for the SI and SHM of mechanical systems, this study is to test the reliability of the method against real data. Te experimental case study selected to extensively test the LF's capabilities to detect and track changes in the mechanical properties of the system (both mass and stifness), even under noisy conditions and with nonlinearities added to the system, is the well-known [45][46][47][48] three-storey frame structure benchmark experiment performed at the EI at the LANL [49,50].…”

Section: Experimental Case Studymentioning

confidence: 99%

A Loewner-Based System Identification and Structural Health Monitoring Approach for Mechanical Systems

Dessena

Civera

Fragonara

et al. 2023

Structural Control and Health Monitoring

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Data-driven structural health monitoring (SHM) requires precise estimates of the target system behaviour. In this sense, SHM by means of modal parameters is strictly linked to system identification (SI). However, existing frequency-domain SI techniques have several theoretical and practical drawbacks. This paper proposes using an input-output system identification technique based on rational interpolation, known as the Loewner framework (LF), to estimate the modal properties of mechanical systems. Pioneeringly, the Loewner framework mode shapes and natural frequencies estimated by LF are then applied as damage-sensitive features for damage detection. To assess its capability, the Loewner framework is validated on both numerical and experimental datasets and compared to established system identification techniques. Promising results are achieved in terms of accuracy and reliability.

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Instantaneous Spectral Entropy: An Application for the Online Monitoring of Multi-Storey Frame Structures

Cited by 26 publications

References 48 publications

A novel ultrasonic inspection method of the heat exchangers based on circumferential waves and deep neural networks

A novel ultrasonic inspection method of the heat exchangers based on circumferential waves and deep neural networks

Applications of the Generalized Morse Wavelets: A Review

A Loewner-Based System Identification and Structural Health Monitoring Approach for Mechanical Systems

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