Crack identification in beams using Hilbert transform, kurtosis and mode shape rotation deviation curve

2013 ◽  
Vol 21 (8) ◽  
pp. 1392-1416 ◽  
Author(s):  
H. Kucukgoncu ◽  
K. Aydin
Keyword(s):  
Hilbert Transform ◽  
Mode Shape ◽  
Crack Identification

Rotor Crack Identification Based on Mode Shape and Derivative Order Using Combination Resonances

2019 ◽  
Author(s):  
Izabela Batista da Silva ◽  
Paulo Costa Porto de Figueiredo Barbosa ◽  
Aldemir Ap Cavalini Jr ◽  
Valder Steffen Jr ◽  
Nicolò Bachschmid
Keyword(s):  
Mode Shape ◽  
Crack Identification ◽  
Derivative Order

scholarly journals Mode shape curvature of multiple cracked beam and its use for crack identification in beam-like structures

2020 ◽  
Author(s):  
Nguyen Tien Khiem
Keyword(s):  
Finite Difference ◽  
Mode Shape ◽  
Crack Detection ◽  
Exact Expression ◽  
Finite Difference Approximation ◽  
Theoretical Development ◽  
Difference Approximation ◽  
Crack Identification ◽  
Cracked Beam ◽  
Modal Curvature

The problem of using the modal curvature for crack detection is discussed in this paper based on an exact expression of mode shape and its curvature. Using the obtained herein exact expression for the mode shape and its curvature, it is demonstrated that the mode shape curvature is really more sensitive to crack than mode shape itself. Nevertheless, crack-induced change in the approximate curvature calculated from the exact mode shape by the central finite difference technique (Laplacian) is much greater in comparison with both the mode shape and curvature. It is produced by the fact, shown in this study, that miscalculation of the approximate curvature is straightforwardly dependent upon crack magnitude and resolution step of the finite difference approximation. Therefore, it can be confidently recommended to use the approximate curvature for multiple crack detection in beam by properly choosing the approximation mesh. The theoretical development has been illustrated by numerical results.

Fatigue Crack Identification in Tensile-Shear Spot Welded Joints by Dynamic Response Characteristics

2005 ◽  
Vol 127 (3) ◽  
pp. 310-317 ◽  
Author(s):  
G. Wang ◽  
M. E. Barkey
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Mode Shape ◽  
Crack Identification ◽  
Tensile Shear ◽  
Modal Shape ◽  
Element Analysis ◽  
Response Characteristics ◽  
Crack Location ◽  
Spot Welded

A theoretical model for the estimation of fatigue crack length of tensile-shear spot welded specimen is developed which incorporates the natural frequency and mode variation. The model is based on the concept that the propagation of cracks causes a release of strain energy, which is related to the structural modal shape. The effect of the structural mode shape and crack location is also explained. The model, experimental, and finite element results indicate that the existence of cracks cause the reduction of natural frequencies and change of natural modes, and that the mode shape of the structure and crack location will affect the magnitude of the change of these dynamic variables. The predictions of the model are compared with the experimental data and finite element analysis results and agreement is found to be consistent.

scholarly journals Crack identification based on the nonlinear response of plates with variably oriented surface crack.

2018 ◽  
Vol 149 ◽  
pp. 02061
Author(s):  
H. Chouiyakh ◽  
L. Azrar ◽  
K. Alnefaie ◽  
O. Akourri
Keyword(s):  
Hilbert Transform ◽  
Surface Crack ◽  
Structural Integrity ◽  
Plate Theory ◽  
Differential Quadrature Method ◽  
Crack Identification ◽  
Rectangular Plates ◽  
Cracked Plates ◽  
Line Spring Model ◽  
Linear And Nonlinear

In order to secure structural and operational safety of structures, it is important to implement a structural health monitoring (SHM) strategy to issue early warnings on damage or deterioration prior to costly repair or even catastrophic collapse. Developing a SHM strategy for structures enables evaluating structural integrity, durability and reliability of the monitored structure. Hence, the main objective of this work is to develop a damage detection procedure based on a plate’s dynamic response and the Hilbert transform. Rectangular plates are considered and assumed to contain a surface crack which is centrally located, with a depth of h0, a length of 2C and inclined with an angle β. Von Karman plate theory is adopted herein, and the crack is modeled through the line spring model given by fracture mechanics. The plate is assumed to behave nonlinearly due to large deformation. The differential quadrature method is used to investigate the linear and nonlinear dynamic behaviors of cracked plates. The influence of crack’s parameters on modal properties is discussed. The eigenfrequencies of cracked plates with respect to crack half length C and orientation β are performed. For crack characterization, Hilbert transform is applied to the obtained linear and nonlinear time responses. It is shown throughout this paper that identified backbones describe changes in crack orientation.

Hilbert transform and spectral kurtosis based approach in identifying the health state of retrofitted old steel truss bridge

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anshul Sharma ◽  
Pardeep Kumar ◽  
Hemant Kumar Vinayak ◽  
Suresh Kumar Walia ◽  
Raj Kumar Patel
Keyword(s):  
Hilbert Transform ◽  
Mode Shape ◽  
Vibration Response ◽  
Content Type ◽  
Spectral Kurtosis ◽  
Steel Truss Bridge ◽  
Steel Truss ◽  
Filtering Technique ◽  
Stockwell Transform ◽  
Truss Bridge

Purpose This study aims to include the diagnosis of an old concrete deck steel truss rural road bridge in the damaged and retrofitted state through vibration response signals. Design/methodology/approach The analysis of the vibration response signals is performed in time and time-frequency domains using statistical features-root mean square, impulse factor, crest factor, kurtosis, peak2peak and Stockwell transform. The proposed methodology uses the Hilbert transform in combination with spectral kurtosis and bandpass filtering technique for obtaining robust outcomes of modal frequencies. Findings The absence or low amplitude of considered mode shape frequencies is observed both before and after retrofitting of bridge indicates the deficient nodes. The kurtosis feature among all statistical approaches is able to reflect significant variation in the amplitude of different nodes of the bridge. The Stockwell transform showed better resolution of present modal frequencies but due to the yield of additional frequency peaks in the vicinity of the first three analytical modal frequencies no decisive conclusions are achieved. The methodology shows promising outcomes in eliminating noise and visualizing distinct modal frequencies of a steel truss bridge. Social implications The findings of the present study help in analyzing noisy vibration signals obtained from various structures (civil or mechanical) and determine vulnerable locations of the structure using mode shape frequencies. Originality/value The literature review gave an insight into few experimental investigations related to the combined application of Hilbert transform with spectral kurtosis and bandpass filtering technique in determining mode frequencies of a steel truss bridge.

Model of multicomponent narrow-band periodical non-stationary random signal

2020 ◽  
Vol 2020 (48) ◽  
pp. 17-24
Author(s):  
I.M. Javorskyj ◽  
◽  
R.M. Yuzefovych ◽  
P.R. Kurapov ◽  
◽  
...  
Keyword(s):  
Time Series ◽  
Real Time ◽  
Hilbert Transform ◽  
Spectral Properties ◽  
Narrow Band ◽  
Analytic Signal ◽  
Random Signal ◽  
Hilbert Transformation ◽  
The Hilbert Transform

The correlation and spectral properties of a multicomponent narrowband periodical non-stationary random signal (PNRS) and its Hilbert transformation are considered. It is shown that multicomponent narrowband PNRS differ from the monocomponent signal. This difference is caused by correlation of the quadratures for the different carrier harmonics. Such features of the analytic signal must be taken into account when we use the Hilbert transform for the analysis of real time series.

A Bayesian View on the Hilbert Transform and the Kramers-Kronig Transform of Electrochemical Impedance Data: Probabilistic Estimates and Quality Scores

2020 ◽  
Author(s):  
Jiapeng Liu ◽  
Ting Hei Wan ◽  
Francesco Ciucci
Keyword(s):  
Power Generation ◽  
Electrochemical Impedance Spectroscopy ◽  
Hilbert Transform ◽  
Electrochemical Impedance ◽  
The Self ◽  
Impedance Data ◽  
The Hilbert Transform ◽  
Validation Tests ◽  
Self Consistency ◽  
Mathematical Relations

<p>Electrochemical impedance spectroscopy (EIS) is one of the most widely used experimental tools in electrochemistry and has applications ranging from energy storage and power generation to medicine. Considering the broad applicability of the EIS technique, it is critical to validate the EIS data against the Hilbert transform (HT) or, equivalently, the Kramers–Kronig relations. These mathematical relations allow one to assess the self-consistency of obtained spectra. However, the use of validation tests is still uncommon. In the present article, we aim at bridging this gap by reformulating the HT under a Bayesian framework. In particular, we developed the Bayesian Hilbert transform (BHT) method that interprets the HT probabilistic. Leveraging the BHT, we proposed several scores that provide quick metrics for the evaluation of the EIS data quality.<br></p>

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