Damage identification of beam structures using free response shapes obtained by use of a continuously scanning laser Doppler vibrometer system

Xu, Yongfeng; Chen, Daming; Zhu, Weidong

doi:10.1016/j.ymssp.2016.12.042

Cited by 46 publications

(16 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the latter is usually unavailable in practice. It has been shown in Xu et al (2014Xu et al ( , 2017 and Chen et al (2016Chen et al ( , 2017Chen et al ( , 2018c) that a polynomial that fits a mode shape of a damaged structure can well approximate that of the associated undamaged structure, which can be expressed by…”

Section: Baseline-free Structural Damage Identificationmentioning

confidence: 99%

“…A set of frequency response functions between lifted CSLDV measurements and excitation by an impact can be obtained and analyzed to estimate modal parameters of the structure. A new type of vibration shape, called a free response shape, was developed based on the demodulation method (Xu et al, 2017). Multiple free response shapes corresponding to a mode of a structure undergoing free vibration can be obtained and used for baselinefree structural damage identification.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Operational modal analysis using lifted continuously scanning laser Doppler vibrometer measurements and its application to baseline-free structural damage identification

Chen

Zhu

2019

Journal of Vibration and Control

Self Cite

View full text Add to dashboard Cite

A continuously scanning laser Doppler vibrometer (CSLDV) system is capable of efficient and spatially dense vibration measurements by sweeping its laser spot along a scan path assigned on a structure. This paper proposes a new operational modal analysis (OMA) method based on a data processing method for CSLDV measurements of a structure, called the lifting method, under white-noise excitation and applies a baseline-free method to identify structural damage using estimated mode shapes from the OMA method. The lifting method enables transformation of raw CSLDV measurements into measurements at individual virtual measurement points, as if the latter were made by use of an ordinary scanning laser Doppler vibrometer in a step-wise manner. It is shown that a correlation function with nonnegative time delays between lifted CSLDV measurements at two virtual measurement points on a structure under white-noise excitation and its power spectrum contain modal parameters of the structure, that is, natural frequencies, modal damping ratios, and mode shapes. The modal parameters can be estimated by using a standard OMA algorithm. A major advantage of the proposed OMA method is that curvature mode shapes associated with mode shapes estimated by the method can reflect local anomaly caused by small-sized structural damage, while those estimated by other existing OMA methods that use CSLDV measurements cannot. Numerical and experimental investigations are conducted to study the OMA method and baseline-free structural damage identification method. In the experimental investigation, effects of the scan frequency of a CSLDV system on the two methods were studied. It is shown in both the numerical and experimental investigations that modal parameters can be accurately estimated by the OMA method and structural damage can be successfully identified in neighborhoods with consistently high values of curvature damage indices.

show abstract

Section: Baseline-free Structural Damage Identificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Operational modal analysis using lifted continuously scanning laser Doppler vibrometer measurements and its application to baseline-free structural damage identification

Chen

Zhu

2019

Journal of Vibration and Control

Self Cite

View full text Add to dashboard Cite

show abstract

“…CSLDV techniques well-suit structural integrity analysis for damage detection and identification and, in fact, several papers are available to this account. CSLDV techniques were attempted to either cracked beams or plates embedding damages, and these researches can be read in [15][16][17][18][19][20][21][22][23][24][25][26][27]. One of the most distinctive features of all the CSLDV papers, cited in here, is the recovery of the ODS(s) as means for further investigation of damage detection and identification.…”

Section: Introductionmentioning

confidence: 99%

Diagnostics Based on Continuous Scanning LDV Measurements and RASTAR Analysis Method

2020

View full text Add to dashboard Cite

This paper presents a technique for rapid diagnostics of structural integrity that exploits spectral sidebands measured by the continuous scanning LDV (CSLDV) measurement method. Structural integrity can be monitored by Operational Deflection Shapes ODSs, which can be quickly measurable at any excitation frequency when a laser continuously scans a vibrating surface. The LDV output time series is an amplitude modulated signal, and its spectral lines are used for recovering polynomial coefficients which build a polynomial function describing a deflection shape. The process of conversion from the time series to a polynomial function can be biased by measurement and analysis uncertainty which eventually will affect the quality of recovered ODS. This paper will show that an effective, rapid and straightforward diagnostics can be yielded by direct analysis of the spectral sidebands without the need to be transformed into polynomial coefficients. The Relative Amplitude of the Sidebands to the Total Amplitude Reference (RASTAR) method is an indicator that exploits the relative amplitude of the sidebands against a datum reference. The relative magnitudes of the sidebands will not change in the absence of any the structural change, and it is independent of the vibration response amplitudes set for the measurements. Such diagnostic method suits maintenance operations of structures which could be quickly scanned by an SLDV system providing an indicative level of structural integrity over the number of duty cycles.

show abstract

“…PE method has several advantages over some traditional vibration-based methods [26,27]. Firstly, structural damage is identified by using the measured displacement of damaged structures without requiring the baseline data on pristine structures or benchmark structures.…”

Section: Introductionmentioning

confidence: 99%

Adaptive damage localization based on locally perturbed dynamic equilibrium and hierarchical clustering

Cao

Ouyang

Cheng

2019

Smart Mater. Struct.

View full text Add to dashboard Cite

Pseudo-excitation (PE) method is a recently developed damage identification method for flexible structures containing components like beams, plates and shells. Characterized by the high-order spatial derivatives, the approach has been shown to feature a high sensitivity to local damage. However, two major issues, i.e. susceptibility to measurement noise and unknown material/ structural properties, hamper its practical applications. To tackle these problems, an adaptive damage localization method is proposed for plate-type structures, which combines the PE method with hierarchical clustering. In the proposed method, a general dynamic equilibrium model, involving unknown material/structural properties, is statistically identified and further used for damage localization. Moreover, noise-induced effects are quantified by using a hierarchical clustering for performance assessment of damage localization and process optimization of spatial derivative estimation to achieve more accurate damage localization. Meanwhile, a data fusion scheme is developed to avoid blind inspection zones, thus enhancing the capability of damage localization. Both numerical and experimental studies of cantilever plates containing two damage zones are conducted to validate the feasibility and the effectiveness of the proposed adaptive damage localization method. Results demonstrate that the proposed method outperforms the traditional PE method in terms of detection accuracy and robustness.

show abstract

Damage identification of beam structures using free response shapes obtained by use of a continuously scanning laser Doppler vibrometer system

Cited by 46 publications

References 29 publications

Operational modal analysis using lifted continuously scanning laser Doppler vibrometer measurements and its application to baseline-free structural damage identification

Operational modal analysis using lifted continuously scanning laser Doppler vibrometer measurements and its application to baseline-free structural damage identification

Diagnostics Based on Continuous Scanning LDV Measurements and RASTAR Analysis Method

Adaptive damage localization based on locally perturbed dynamic equilibrium and hierarchical clustering

Contact Info

Product

Resources

About