A Finite Wavelet Domain Method for the Rapid Simulation of Wave SHM Systems in Composite Plate Strips for Impact and Damage Detection

2015 ◽  
Author(s):  
NASTOS CHRISTOS ◽  
THEODOSIS THEODOSIOU ◽  
CHRISTOFOROS REKATSINAS ◽  
DIMITRIS SARAVANOS
Keyword(s):  
Damage Detection ◽  
Composite Plate ◽  
Wavelet Domain ◽  
Domain Method

A Round Robin Study: Detection of Damage in a Composite Plate With a Real-Time Moving Sensor Measurement Technique

2018 ◽  
Author(s):  
Da-Ming Chen ◽  
Y. F. Xu ◽  
W. D. Zhu
Keyword(s):  
Damage Detection ◽  
Real Time ◽  
Composite Plate ◽  
Detection Method ◽  
Damage Index ◽  
Laser Doppler Vibrometer ◽  
Composite Plates ◽  
Round Robin ◽  
Velocity Response ◽  
Demodulation Method

A worldwide round robin study is sponsored by the Society of Experimental Mechanics to detect damage in a composite plate with a scanning laser Doppler vibrometer (SLDV). The aim of this round robin study is to explore the potential of a SLDV for detection of damage in composite plates. In this work, a curvature-based damage detection method with use of a continuously SLDV (CSLDV) is proposed. A CSLDV can be regarded as a real-time moving sensor, since the laser spot from the CSLDV continuously moves on a structure surface and measures velocity response. An operating deflection shape (ODS) of the damaged composite plate can be obtained from velocity response by the demodulation method. The ODS of the associated undamaged composite plate is obtained by using polynomials to fit the ODS of the damaged plate. A curvature damage index (CDI) using differences between curvatures of ODSs (CODSs) associated with the ODSs from the demodulation method and the polynomial fit is proposed to detect damage. With the proposed curvature-based damage detection method, locations of two possible damage are detected in areas with consistently high CDI values at two excitation frequencies, which are in good agreement with prescribed damage locations.

Response-Only Frequency-Domain Method for Structural Damage Detection

2009 ◽  
Author(s):  
Shuncong Zhong ◽  
S. Olutunde Oyadiji
Keyword(s):  
Damage Detection ◽  
Frequency Domain ◽  
Natural Frequency ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Frequency Domain Method ◽  
Structural Damage Detection ◽  
Frequency Curve ◽  
Domain Method ◽  
Auxiliary Mass

This paper proposes a response-only method in frequency domain for structural damage detection by using the derivative of natural frequency curve of beam-like structures with a traversing auxiliary mass. The approach just uses the response time history of beam-like structures and does not need the external source of force excitation. The natural frequencies of a damaged beam with a traversing auxiliary mass change due to change in flexibility and inertia of the beam as the auxiliary mass is traversed along the beam. Therefore the auxiliary mass can enhance the effects of the crack on the dynamics of the beam and, therefore, facilitating locating the damage in the beam. That is, the auxiliary mass can be used to probe the dynamic characteristic of the beam by traversing the mass from one end of the beam to the other. However, it is impossible to obtain accurate modal frequencies by the direct operation of the Fast Fourier Transform of the response data of the structure because the frequency spectrum can be only calculated from limited sampled time data which results in the well-known leakage effect. A spectrum correction method is employed to estimate high accurate frequencies of structures with a traversing auxiliary mass. In the present work, the modal responses of damaged simply supported beams with auxiliary mass are computed using the Finite Element Analysis. The graphical plots of the natural frequencies versus axial location of auxiliary mass are obtained. The derivatives of natural frequency curve can provide crack information for damage detection of beam-like structures. However, it is suggested that the derivative do not go beyond the third derivative of natural frequency curves to avoid the difference approximation error which will be magnified at higher derivative. The sensitivity of crack index for different noise, crack depth, auxiliary mass and damping ratio are also investigated. The simulated result demonstrated the efficiency and precision of the response-only frequency-domain method which can be recommended for the real application in structural damage detection.

Finite Element Simulation of Lamb Wave with Piezoelectric Transducers for Composite Plate Damage Detection

2009 ◽  
Vol 79-82 ◽  
pp. 1095-1098 ◽  
Author(s):  
Wen Zhong Qu ◽  
Li Xiao
Keyword(s):  
Finite Element ◽  
Damage Detection ◽  
Finite Element Simulation ◽  
Lamb Wave ◽  
Composite Plate ◽  
Lamb Waves ◽  
Piezoelectric Transducers ◽  
Thin Plates ◽  
Diagnostic Tools ◽  
Element Simulation

Structural health monitoring (SHM) is an emerging research area with multiple applications. Lamb waves are ultrasonic elastic waves that travel inside and along thin plates and is frequently used as diagnostic tools to detect damage in plate-like structures. In this paper, a transient dynamic finite element simulation of Lamb wave with piezoelectric transducers for damage detection in a composite plate is carried out. The embedded cross-shaped piezoelectric active sensor arrays were used to generate and receive guided Lamb waves propagating in the plate structure. A full-scale FEM model for the laminate was created using three-dimensional eight-node layered structural solid element and piezoelectric active sensors were created using coupled field elements on the commercial finite element code ANSYS platform. The beam forming technique of Lamb waves is used to locate damage in the plate .The results of the numerical simulation demonstrate the effectiveness of the approach.

Investigation of the Effectiveness of Different Thermographic Testing Modalities in Damage Detection

2013 ◽  
Vol 558 ◽  
pp. 349-356 ◽  
Author(s):  
Łukasz Pieczonka ◽  
Mariusz Szwedo ◽  
Tadeusz Uhl
Keyword(s):  
Nondestructive Testing ◽  
Comparative Study ◽  
Damage Detection ◽  
Composite Plate ◽  
Impact Damage ◽  
Experimental Testing ◽  
Diagnostic System ◽  
Software Components ◽  
Pulsed Thermography

The paper deals with practical aspects of Thermographic Nondestructive Testing (TNDT). A comparative study of burst vibrothermography (VT) and pulsed thermography (PT) measurements is presented and discussed. The authors have developed a diagnostic system for thermographic testing of structures that was used to perform experiments. Supported test modalities include burst vibrothermography and pulsed thermography, among other techniques. The system comprises both hardware and software components facilitating TNDT inspections. Experimental testing has been performed, on a composite plate, using the developed diagnostic system and two of the supported test modalities. The goal of these investigations was to compare the performance of both TNDT methods in revealing Barely Visible Impact Damage (BVID) in a composite plate.

Substructural Response Reconstruction in Wavelet Domain

2011 ◽  
Vol 78 (4) ◽  
Author(s):  
J. Li ◽  
S. S. Law
Keyword(s):  
Degrees Of Freedom ◽  
Sampling Rate ◽  
Impulse Response Function ◽  
Frame Structure ◽  
Frequency Domain Method ◽  
Wavelet Domain ◽  
Data Sampling ◽  
Sampled Data ◽  
Domain Method ◽  
Response Reconstruction

An approach for structural response reconstruction in a substructure using the unit impulse response function in the wavelet domain is presented. The forces at the interface degrees-of-freedom are taken as input excitations on the substructure. The response reconstruction is conducted by transforming the measured responses into responses at other selected locations. The response reconstruction using the proposed wavelet domain method is then compared with that from an existing frequency domain method. Numerical studies on a seven-story plane frame structure are carried out to investigate the accuracy and effectiveness of the proposed method, and the effects of influencing parameters such as the number of sampled data, sampling rate, sensor numbers, and measurement noise are studied.

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