scholarly journals Core–skin debonding detection in honeycomb sandwich structures through guided wave wavefield analysis

2018 ◽  
Vol 30 (9) ◽  
pp. 1306-1317 ◽  
Author(s):  
Lingyu Yu ◽  
Zhenhua Tian ◽  
Xiaopeng Li ◽  
Rui Zhu ◽  
Guoliang Huang
Keyword(s):  
Guided Waves ◽  
Sandwich Structures ◽  
Lamb Waves ◽  
Laser Doppler Vibrometer ◽  
Low Frequency ◽  
Guided Wave ◽  
Honeycomb Sandwich ◽  
Debonding Detection ◽  
The Waves ◽  
Detection And Quantification

Ultrasonic guided waves have proven to be an effective and efficient method for damage detection and quantification in various plate-like structures. In honeycomb sandwich structures, wave propagation and interaction with typical defects such as hidden debonding damage are complicated; hence, the detection of defects using guided waves remains a challenging problem. The work presented in this article investigates the interaction of low-frequency guided waves with core–skin debonding damage in aluminum core honeycomb sandwich structures using finite element simulations. Due to debonding damage, the waves propagating in the debonded skin panel change to fundamental antisymmetric Lamb waves with different wavenumber values. Exploiting this mechanism, experimental inspection using a non-contact laser Doppler vibrometer was performed to acquire wavefield data from pristine and debonded structures. The data were then processed and analyzed with two wavefield data–based imaging approaches, the filter reconstruction imaging and the spatial wavenumber imaging. Both approaches can clearly indicate the presence, location, and size of the debonding in the structures, thus proving to be effective methods for debonding detection and quantification for honeycomb sandwich structures.

scholarly journals Improving accuracy through density correction in guided wave tomography

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150832 ◽  
Author(s):  
P. Huthwaite
Keyword(s):  
Guided Waves ◽  
Low Frequency ◽  
Region Of Interest ◽  
Density Variation ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Wave Tomography ◽  
Wall Loss ◽  
Improving Accuracy ◽  
The Waves

The accurate quantification of wall loss caused by corrosion is critical to the reliable life estimation of pipes and pressure vessels. Traditional thickness gauging by scanning a probe is slow and requires access to all points on the surface; this is impractical in many cases as corrosion often occurs where access is restricted, such as beneath supports where water collects. Guided wave tomography presents a solution to this; by transmitting guided waves through the region of interest and exploiting their dispersive nature, it is possible to build up a map of thickness. While the best results have been seen when using the fundamental modes A0 and S0 at low frequency, the complex scattering of the waves causes errors within the reconstruction. It is demonstrated that these lead to an underestimate in wall loss for A0 but an overestimate for S0. Further analysis showed that this error was related to density variation, which was proportional to thickness. It was demonstrated how this could be corrected for in the reconstructions, in many cases resulting in the near-elimination of the error across a range of defects, and greatly improving the accuracy of life estimates from guided wave tomography.

Online Guided Wave-Based Debonding Detection in Honeycomb Sandwich Structures

AIAA Journal ◽  
2012 ◽  
Vol 50 (2) ◽  
pp. 284-293 ◽  
Author(s):  
F. Song ◽  
G. L. Huang ◽  
G. K. Hu
Keyword(s):  
Sandwich Structures ◽  
Guided Wave ◽  
Honeycomb Sandwich ◽  
Debonding Detection

Study of Guided Wave Propagation in Honeycomb Sandwich Structures

2014 ◽  
Author(s):  
Zhenhua Tian ◽  
Guoliang Huang ◽  
Lingyu Yu
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Sandwich Structures ◽  
Guided Wave ◽  
Experimental Results ◽  
Fe Model ◽  
Laser Vibrometry ◽  
Honeycomb Core ◽  
Guided Wave Propagation ◽  
Honeycomb Sandwich

This paper studies the guided waves in honeycomb sandwich structures and explores the ability of guided waves for the debonding damage detection. Both the finite element (FE) simulations and laser vibrometry experiments are used. A three-dimensional (3D) FE model is built to simulate the guided waves in a honeycomb sandwich plate. The simulation results show the guided waves in the structure depend on the wave frequency. At low frequencies, the global guided waves propagate in the entire sandwich, while leaky guided waves dominate in the skin panel at high frequencies. To further understand the guided wave propagation fundamentals, laser vibrometry experiments are performed. The waveforms, time-space wavefields, and frequency-wavenumber spectra obtained from the experiments are used to unveil the wave propagation features. The experimental results confirm the leaky guided waves. Moreover, the experimental results show the complex wave interactions induced by the honeycomb core. When the debonding between the skin and honeycomb core presents, the guided wave amplitude increases, and the wave interaction with the honeycomb core reduces.

Inspection of Concrete-Metal Rod Interface Using Guided Waves

2000 ◽  
Author(s):  
Won-Bae Na ◽  
Tribikram Kundu ◽  
Mohammad R. Ehsani
Keyword(s):  
Lamb Wave ◽  
Guided Waves ◽  
Lamb Waves ◽  
Guided Wave ◽  
Ultrasonic Transducers ◽  
Interface Debonding ◽  
Long Distance ◽  
Steel Rebar ◽  
Steel Bars ◽  
Steel Rebars

Abstract The feasibility of detecting interface degradation and separation of steel rebars in concrete beams using Lamb waves is investigated in this paper. It is shown that Lamb waves can easily detect these defects. A special coupler between the steel rebar and ultrasonic transducers has been used to launch non-axisymmetric guided waves in the steel rebar. This investigation shows that the Lamb wave inspection technique is an efficient and effective tool for health monitoring of reinforced concrete structures because the Lamb wave can propagate a long distance along the reinforcing steel bars embedded in concrete as the guided wave and is sensitive to the interface debonding between the steel rebar and concrete.

Early Fatigue Damage Evaluation of Nonlinear Guided Wave Imaging in Hyperelastic Materials

2021 ◽  
Author(s):  
Chengwei Zhao ◽  
Sunia Tanweer ◽  
Jian Li ◽  
Min Lin ◽  
Xiang Zhang ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Guided Waves ◽  
Lamb Waves ◽  
Tone Burst ◽  
Guided Wave ◽  
Third Order ◽  
Hyperelastic Materials ◽  
Third Order Elastic Constants ◽  
Wave Imaging ◽  
Processing Platform

Abstract Nonlinear ultrasonic guided waves have superior sensitivity of the early fatigue damage. This paper investigates the analysis of the second harmonics of Lamb waves in a free boundary aluminum plate, and the internal resonance conditions between the Lamb wave primary modes and the second harmonics. The Murnaghan’s model is implemented in a finite element (FE) analysis to describe the hyperelastic constitutive relation for nonlinear acoustic modeling. The second harmonics of s0 mode are actuated by a 60kHz Hanning-windowed tone burst. A guided wave signal processing platform is developed for tomographic imaging. The different stages of fatigue are reflected by the changes of third-order elastic constants (TOECs) in Murnaghan’s model. The reconstructed damage locations match well with the actual ones cross different degrees and depths of fatigue.

scholarly journals Warped Wigner-Hough Transform for Defect Reflection Enhancement in Ultrasonic Guided Wave Monitoring

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Luca De Marchi ◽  
Emanuele Baravelli ◽  
Giampaolo Cera ◽  
Nicolò Speciale ◽  
Alessandro Marzani
Keyword(s):  
Hough Transform ◽  
Guided Waves ◽  
Lamb Waves ◽  
Guided Wave ◽  
Nonlinear Signal Processing ◽  
Localization Accuracy ◽  
Time Frequency ◽  
Ultrasonic Guided Wave ◽  
Inspection Systems ◽  
Nonlinear Signal

To improve the defect detectability of Lamb wave inspection systems, the application of nonlinear signal processing was investigated. The approach is based on a Warped Frequency Transform (WFT) to compensate the dispersive behavior of ultrasonic guided waves, followed by a Wigner-Ville time-frequency analysis and the Hough Transform to further improve localization accuracy. As a result, an automatic detection procedure to locate defect-induced reflections was demonstrated and successfully tested by analyzing numerically simulated Lamb waves propagating in an aluminum plate. The proposed method is suitable for defect detection and can be easily implemented for real-world structural health monitoring applications.

CALCULATION OF DISPERSION CURVES FOR ARBITRARY WAVEGUIDES USING FINITE ELEMENT METHOD

2014 ◽  
Vol 06 (05) ◽  
pp. 1450059 ◽  
Author(s):  
KAIGE ZHU ◽  
DAINING FANG
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Guided Waves ◽  
Dispersion Curves ◽  
Guided Wave ◽  
Sandwich Plates ◽  
Multilayered Structures ◽  
Finite Element Software ◽  
Honeycomb Sandwich ◽  
Element Method

Dispersion curves for waveguide structures are an important prerequisite for the implementation of guided wave-based nondestructive evaluation (NDE) approach. Although many methods exist, each method is only applicable to a certain type of structures, and also requires complex programming. A Bloch theorem-based finite element method (FEM) is proposed to obtain dispersion curves for arbitrary waveguides using commercial finite element software in this paper Dispersion curves can be obtained for a variety of structures, such as homogeneous plates, multilayered structures, finite cross section rods and honeycomb sandwiches. The propagation of guided waves in honeycomb sandwich plates and beams are discussed in detail. Then, dispersion curves for honeycomb sandwich beams are verified by experiments.

Noncontact/Remote Material Characterization Using Ultrasonic Guided Wave Methods

2020 ◽  
Author(s):  
Zhaoyun Ma ◽  
Lingyu Yu
Keyword(s):  
Guided Waves ◽  
Broad Band ◽  
Laser Doppler Vibrometer ◽  
Pulsed Laser ◽  
Guided Wave ◽  
Target Plate ◽  
Ultrasonic Guided Wave ◽  
Time Space ◽  
Aluminum Plates ◽  
Wave Methods

Abstract Noncontact and remote NDE systems and methods are highly desired in a broad range of engineering applications such as material property characterization. This paper aims to develop such a noncontact/remote NDE system based on laser ultrasonic guided waves and establish its fundamental capability for material thickness evaluation. The noncontact system employs pulsed laser (PL) for guided wave actuation and scanning laser Doppler vibrometer (SLDV) for guided wave wavefield sensing. A cylindrical planoconvex lens is adopted to focus the pulsed laser beam to a line source in order to excite broad band signals in the target plate. Aluminum plates with different thicknesses are evaluated through SLDV line scans and 2D time-space wavefields are acquired. Frequency-wavenumber (f-k) spectra are obtained through 2D Fourier transform, and the A0 dispersion curve for each plate is extracted. Through Comparing the extracted A0 curve with the theoretical A0 dispersion curves, the thicknesses of the tested plates are identified. Reflective tape effect on the plates are also studied: the reflective tape attached for SLDV enhancement affects the guided waves in the target plate significantly when the plate is relatively thin.

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