scholarly journals The Detection of Impact Damage to the Edges of CFRP Plates Using Extensional Ultrasonic Edge Waves

2021 ◽  
Vol 40 (4) ◽  
Author(s):  
Jun Yu Harry Chu ◽  
Charles R. P. Courtney
Keyword(s):  
Damage Detection ◽  
Impact Damage ◽  
Damage Model ◽  
Composite Plates ◽  
Propagation Distance ◽  
Time Of Arrival ◽  
Edge Waves ◽  
Plate Edge ◽  
Carbon Fibre Reinforced Polymer ◽  
Pulse Echo

AbstractExtensional edge waves propagate along the edges of plates, with low attenuation in the propagation direction and amplitude decreasing rapidly (within one or two wavelengths) in the direction perpendicular to the plate edge. This makes them an ideal candidate for inspecting the edges of plate-like structures. Here, finite-element models and experiments are used to investigate the propagation and scattering of extensional edge waves in composite plates and application to damage detection is demonstrated. Piezoceramic transducers attached to the edge of a 4-mm-thick carbon-fibre-reinforced polymer (CFRP) plate were used to excite 140-kHz edge waves and damage detection demonstrated using two experimental configurations: pitch-catch and two-transducer pulse-echo. Damage due to edge-on impacts of 5 J and 10 J were detected in both configurations. A mass-addition damage model was used to investigate the effect of damage location. Detection was specific to damage within 33 mm (1.5 wavelengths) of the plate edge with propagation unaffected by features beyond that distance. The time of arrival of reflected signals in pulse-echo mode was accurately predicted using the edge-wave group velocity indicating that this configuration can be used for locating damage on edges. The localisation of edge waves means that they can specifically detect damage at the edges of structures, and attenuation measurements indicate that their useful propagation distance is large (5.5 m).

Assessing the Scaling Subtraction Method for Impact Damage Detection in Composite Plates

2017 ◽  
Vol 36 (2) ◽  
Author(s):  
Maria Cristina Porcu ◽  
Lukasz Pieczonka ◽  
Andrea Frau ◽  
Wieslaw Jerzy Staszewski ◽  
Francesco Aymerich
Keyword(s):  
Damage Detection ◽  
Impact Damage ◽  
Composite Plates ◽  
Subtraction Method

scholarly journals Impact Damage Detection in Composite Plates using a Self-diagnostic Electro-Mechanical Impedance-based Structural Health Monitoring System

2015 ◽  
Vol 06 (04) ◽  
pp. 1550013 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
M. Ghajari ◽  
M. H. Aliabadi
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Health Monitoring ◽  
Impact Damage ◽  
Composite Plates ◽  
Mechanical Impedance ◽  
Experimental Tests ◽  
Health Monitoring System ◽  
Structural Health ◽  
Faulty Sensors

In this work, application of the electro-mechanical impedance (EMI) method in structural health monitoring as a damage detection technique has been investigated. A damage metric based on the real and imaginary parts of the impedance measures is introduced. Numerical and experimental tests are carried out to investigate the applicability of the method for various types of damage, such as debonding between the transducers and the plate, faulty sensors and impact damage in composite plates. The effect of several parameters, such as environmental effects, frequency sweep, severity of damage, location of damage, etc., on the damage metric has been reported.

scholarly journals Damage detection with the fundamental mode of edge waves

2020 ◽  
pp. 147592172092031
Author(s):  
James M Hughes ◽  
Munawwar Mohabuth ◽  
Aditya Khanna ◽  
James Vidler ◽  
Andrei Kotousov ◽  
...  
Keyword(s):  
Damage Detection ◽  
Fundamental Mode ◽  
Rayleigh Waves ◽  
Guided Waves ◽  
Mechanical Damage ◽  
Corrosion Damage ◽  
Propagation Distance ◽  
Wave Mode ◽  
Edge Waves ◽  
Phase And Group Velocities

Detection of mechanical damage using Lamb or Rayleigh waves is limited to relatively simple geometries, yet real structures often incorporate features such as free or clamped edges, welds, rivets, ribs and holes. All these features are potential sources of wave reflections and scattering, which make the application of these types of guided waves for damage detection difficult. However, these features can themselves generate so-called ‘feature-guided’ waves. This article details the first application of the fundamental mode of transient edge waves for detection of mechanical damage. The fundamental edge wave mode (ES0) – a natural analogue to Rayleigh waves – is weakly dispersive and may decay with propagation distance. The phase and group velocities of the ES0 wave mode are close to the fundamental shear horizontal (SH0) and symmetric Lamb (S0) wave modes, at low and high frequencies, respectively. It is therefore quite challenging to excite a single ES0 mode and avoid wave coupling. However, it was found experimentally that at medium range frequencies the ES0 mode can be decoupled from SH0 and S0 modes, and its decay is small, allowing for distant detection of defects and damage along free edges of slender structural components. This article provides a brief theory of edge waves, excitation methodology and successful examples of distant detection of crack-like and corrosion damage in I-beam sections, which are widely applied in engineering and construction.

Localization of Barely Visible Impact Damage (BVID) in Composite Plates

2014 ◽  
Vol 627 ◽  
pp. 217-220 ◽  
Author(s):  
Shi Yang Meng ◽  
Zahra Sharif Khodaei ◽  
M.H. Aliabadi
Keyword(s):  
Damage Detection ◽  
Impact Damage ◽  
Composite Plates ◽  
Structural Features ◽  
Detection Technique ◽  
Stiffened Panel ◽  
Imaging Method ◽  
Flat Panel ◽  
Isotropic Composite ◽  
The Impact

This paper exploits the implementation of a delay-and-sum imaging method using Lamb wave signals to localise barely visible impact damage (BVID) in quasi-isotropic composite panels. The structural discontinuities, such as opening and stiffener, has also been tested to reflect the common structural features of an aircraft and to examine the feasibility of the proposed detection technique. The prediction results are compared with ultrasonic C-scan images, which indicate location error for three different panels –flat panel, flat panel with an opening and stiffened panel. The accuracy is believed to be improved by increasing the number of transducers. Overall the proposed damage detection technique, with the use of only four transducers, demonstrated sufficient accuracy and efficiency in impact damage detection and can be applied alongside the traditional NDT inspections for providing a priori information of the impact damage location.

Simulation of Mechanical Properties of Woven Fabric Laminated Composite Plates at Given Damage State

2005 ◽  
Author(s):  
Jim Lua ◽  
Wenbin Yu ◽  
Ram Mohan ◽  
Jagannathan Sankar
Keyword(s):  
Impact Damage ◽  
Damage Model ◽  
Composite Plates ◽  
Failure Criteria ◽  
Woven Fabric ◽  
Stiffness Degradation ◽  
Continuum Damage ◽  
Damage State ◽  
The Impact ◽  
Delamination Damage

Composite ship structures are subjected to both the low and high velocity impact during their service life. The dynamic impact can generate fiber, matrix and/or delamination damage inside a woven fabric composite laminate, which may significantly reduce its stiffness and strength. Both the structural mechanics and fracture mechanics based models cannot fully capture the impact damage evolution due to coexistence of continuum and discrete damage. The stress and strain at the element level cannot be directly used to predict the constituent damage and the resulting mechanism driven stiffness degradation. In this paper, a hybrid discrete and continuum damage model is developed and numerically implemented within the LS-DYNA environment via a user-defined material model. The continuum damage progression and its associated stiffness degradation are predicted based on the constituent stress/strain and their associated failure criteria while the delamination damage is numerically captured via a cohesive interface model.

Experimental Investigation on Improving Electromechanical Impedance Based Damage Detection by Temperature Compensation

2013 ◽  
Vol 569-570 ◽  
pp. 1132-1139 ◽  
Author(s):  
Thomas Siebel ◽  
Mihail Lilov
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Temperature Compensation ◽  
Impact Damage ◽  
Correlation Coefficients ◽  
Electromechanical Impedance ◽  
Reinforced Plastic ◽  
Influence Of Temperature On ◽  
Compensation Approach ◽  
The Impact

The sensitivity of the electromechanical impedance to structural damage under varying temperature is investigated in this paper. An approach based on maximizing cross-correlation coefficients is used to compensate temperature effects. The experiments are carried out on an air plane conform carbon fiber reinforced plastic (CFRP) panel (500mm x 500mm x 5mm) instrumented with 26 piezoelectric transducers of two different sizes. In a first step, the panel is stepwise subjected to temperatures between-50 °C and 100 °C. The influence of varying temperatures on the measured impedances and the capability of the temperature compensation approach are analyzed. Next, the sensitivity to a 200 J impact damage is analyzed and it is set in relation to the influence of a temperature change. It becomes apparent the impact of the transducer size and location on the quality of the damage detection. The results further indicate a significant influence of temperature on the measured spectra. However, applying the temperature compensation algorithm can reduce the temperature effect at the same time increasing the transducer sensitivity within its measuring area. The paper concludes with a discussion about the trade-off between the sensing area, where damage should be detected, and the temperature range, in which damage within this area can reliably be detected.

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