Unsupervised identification of arbitrarily-damped structures using time-scale independent component analysis: Part II

Farzampour, Alireza; Kamali-Asl, Arash; Hu, Jong Wan

doi:10.1007/s12206-018-0839-8

Cited by 5 publications

(5 citation statements)

References 24 publications

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“…Fourier transform was performed to estimate the maximum spectral amplitude of the ultrasonic waves at each time instance, using continuous wavelet transform (CWT) to decompose time-domain signals into time-frequency maps. [33][34][35][36] Morlet mother wavelet 37 was implemented to generate time-frequency maps of P-and S-waves at representative points. We used the built-in Wavelet Toolbox in MATLAB software to obtain the time-frequency maps.…”

Section: Data Processing Techniquesmentioning

confidence: 99%

Alteration of ultrasonic signatures by stress-induced changes in hydro-mechanical properties of fractured rocks

Kamali-Asl

Ghazanfari

et al. 2021

International Journal of Rock Mechanics and Mining Sciences

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Section: Data Processing Techniquesmentioning

confidence: 99%

Alteration of ultrasonic signatures by stress-induced changes in hydro-mechanical properties of fractured rocks

Kamali-Asl

Ghazanfari

et al. 2021

International Journal of Rock Mechanics and Mining Sciences

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“…Moreover, the amplitude envelope of the three components is also computed, which can be used for the identification of the time-varying damping ratio. To further validate the robustness of the method based on energy analysis, the estimator based on signal amplitude in equation (21) is used to estimate the time-varying damping ratio as a comparison. e identified results are presented in Figures 11-13, and significant fluctuations are observed by using the estimator in equation (21).…”

Section: Simulation Examplementioning

confidence: 99%

“…To further validate the robustness of the method based on energy analysis, the estimator based on signal amplitude in equation (21) is used to estimate the time-varying damping ratio as a comparison. e identified results are presented in Figures 11-13, and significant fluctuations are observed by using the estimator in equation (21). By comparison, the energy method based on half-period integral can effectively resist noise and get higher identification accuracy.…”

Section: Simulation Examplementioning

confidence: 99%

“…HT can process multicomponent signals only when combined with EMD which always has the shortage of modal aliasing and end swing phenomena. For short-time TFA tools like WT [20,21], they are established on the assumption of the considered signal being piecewise stationary in a short time. is means that they essentially use horizontal lines to approximate the IF feature.…”

Section: Introductionmentioning

confidence: 99%

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Instantaneous Modal Parameter Identification of Linear Time‐Varying Systems Based on Chirplet Adaptive Decomposition

Zhang

Shi

2019

Shock and Vibration

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Instantaneous modal parameter identification of time-varying dynamic systems is a useful but challenging task, especially in the identification of damping ratio. This paper presents a method for modal parameter identification of linear time-varying systems by combining adaptive time-frequency decomposition and signal energy analysis. In this framework, the adaptive linear chirplet transform is applied in time-frequency analysis of acceleration response for its higher energy concentration, and the response of each mode can be adaptively decomposed via an adaptive Kalman filter. Then, the damping ratio of the time-varying systems is identified based on energy analysis of component response signal. The proposed method can not only improve the accuracy of instantaneous frequency extraction but also ensure the antinoise ability in identifying the damping ratio. The efficiency of the method is first verified through a numerical simulation of a three-degree-of-freedom time-varying structure. Then, the method is demonstrated by comparing with the traditional wavelet and time-domain peak method. The identified results illustrate that the proposed method can obtain more accurate modal parameters in low signal-to-noise ratio (SNR) scenarios.

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“…To identify the dynamic parameters of the structures, input-output methods are used [3]. Newer methods combine, for example, the wavelet-transformed representation of system responses with an independent component analysis [4,5]. The static, as well as fatigue tests, need to demonstrate that the bike's structure has sufficient strength.…”

Section: Introductionmentioning

confidence: 99%

Experimental Development of Composite Bicycle Frame

Dvořák

Ponížil²,

Kulíšek

et al. 2022

Applied Sciences

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This article focuses on the development of a carbon composite bicycle frame using various experimental methods of structural analysis. Two types of frame specimen were used. The complete frame specimen was tested in accordance with ISO test load cases with the addition of an ergometer test in order to refine the operational strain envelope of such a frame. Resistive strain gauges and optical Fiber Bragg Grating (FBG) sensors were used for this analysis. The FBG sensors were embedded inside the head tube joints during the manufacturing process. The head connection was designed as a geometrically precise form–connection of wound composite tubes, reinforced with a wrap of high-strength unidirectional carbon tapes and carbon fabrics. Additional structural strength laboratory tests were conducted using simplified frame specimens, in order to evaluate the range of the limit case strain ranges. The digital image correlation method was used for the evaluation of the strain distribution in the head tube area. Resistive strain gauges were used for local strain analysis in critical areas. The acoustic emission method was used to detect structural defects before they could influence the stiffness response of the frame. It was found that the joints of the frame tubes are crucial for the strength and safety of the frame. Therefore, attention was also focused on the strengthening of the head tube joint, and on its experimental verification. A positive effect on the strength of the reinforced frame was found by doubling the thickness of the carbon fabric in the head tube joint area.

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Unsupervised identification of arbitrarily-damped structures using time-scale independent component analysis: Part II

Cited by 5 publications

References 24 publications

Alteration of ultrasonic signatures by stress-induced changes in hydro-mechanical properties of fractured rocks

Alteration of ultrasonic signatures by stress-induced changes in hydro-mechanical properties of fractured rocks

Instantaneous Modal Parameter Identification of Linear Time‐Varying Systems Based on Chirplet Adaptive Decomposition

Experimental Development of Composite Bicycle Frame

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