Experimental Model of Impact Damage for Guided Wave-Based Inspection of Composites

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Mohammad H. Sherafat ◽  
Nicolas Quaegebeur ◽  
Pascal Hubert ◽  
Larry Lessard ◽  
Patrice Masson
Keyword(s):  
Experimental Model ◽  
Composite Structures ◽  
Impact Damage ◽  
Incident Angle ◽  
Energy Levels ◽  
Laser Doppler Vibrometer ◽  
Design Guidelines ◽  
Guided Wave ◽  
Antisymmetric Mode ◽  
The Impact

The objective of this work is to assess to which extent the interaction of antisymmetric ultrasonic guided waves with impact damage can be captured with an experimental model consisting of a single artificial delamination in composite structures. The structures of interest are composed of unidirectional prepreg carbon fiber-reinforced polymer (CFRP) with a quasi-isotropic layup. The artificial delamination is introduced into the laminate using two circular Teflon tapes during manufacturing and the realistic damage is simulated by impacting the samples at two energy levels. Two colocalized rectangular piezoceramics are used to generate an antisymmetric mode and noncontact measurement is performed using a three-dimensional (3D) laser Doppler vibrometer (3D-LDV) to extract the required information for evaluation of the reflection, transmission, as well as the scattering behavior of the antisymmetric mode. The corresponding coefficients as a function of frequency, incident angle, and type of damage are extracted. It is found that the amplitude of the coefficients and directivity patterns of scattered waves are barely affected by incident angle but significantly by the impact energy. In light of the results, design guidelines are proposed for efficient guided wave inspection of composite structures submitted to impacts.

scholarly journals Modeling Analysis of Guided Ultrasonic Waves in Composite Plates with Impact Damage

2018 ◽  
Vol 7 (4.26) ◽  
pp. 175
Author(s):  
Noorfaten Asyikin Ibrahim ◽  
Bibi Intan Suraya Murat
Keyword(s):  
Composite Structures ◽  
Impact Damage ◽  
Composite Plates ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Fe Model ◽  
Element Analysis ◽  
Damage Area ◽  
Guided Ultrasonic Waves ◽  
The Impact

This paper investigates the propagation of guided ultrasonic waves and the interaction with impact damage in composite plates using a full three-dimensional Finite Element analysis. Impact damage in the composite plate was modeled as rectangular- and T-shaped delaminations. In order to provide guidelines for extending the modeling of realistic multimode impact damage, the impact damage was modeled as a combination of the delamination and reduced materials properties. The information obtained from these methods was compared to the experimental results around the damage area for a validation. There was a reasonable similarity between the experimental and FE results. The FE simulations can effectively model the scattering characteristics of the A0 mode wave propagation in anisotropic composite plates. This suggests that the simplified and easy-to-implement FE model could be used to represent the complex impact damage in composite plates. This could be useful for the improvement of the FE modeling and performance of guided wave methods for the in-situ NDE of large composite structures. 

Detection of Impact Damage in Composite Plates Using Surface Contact Method

2006 ◽  
Vol 326-328 ◽  
pp. 1693-1696
Author(s):  
Heoung Jae Chun ◽  
Dang Won Kim ◽  
Joon Hyung Byun
Keyword(s):  
Composite Structures ◽  
Lamb Waves ◽  
Impact Damage ◽  
Incident Angle ◽  
Composite Plates ◽  
Wave Form ◽  
Contact Method ◽  
Internal Damage ◽  
Fundamental Causes ◽  
The Impact

It is a well known fact that the fundamental causes of most failures in composite structures are in the forms of incipient damages such as delaminations and cracks which usually remain undetected until they grow to levels large enough to cause failure. In this study, unidirectional carbon/epoxy composite plates with known defects are investigated. The known defects are generated by impacting the composite specimens simulating external collision. A pair of transmitter and receiver was used for generation of Lamb waves and reception of signals. The received signals were monitored by scanning the receiver toward internal defect or by scanning both transmitter and receiver with confined distance over the surface of the composite plates which have known defects lie beneath them. The proper selection of incident angle and frequency are also considered. The characteristics of received signals such as amplitude, energy and wave form are analyzed. The acquired information is used to locate and to measure the size of the impact damage. The suggested method is very effective if the internal damage is presented closed to surface of the plate where the conventional pulse-echo method has problems. The proposed technique can be used widely for the real time and online monitoring of composite structures.

Experimental investigation on a fully thermoplastic composite subjected to repeated impacts

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6985-7002
Author(s):  
S Boria ◽  
A Scattina ◽  
G Belingardi
Keyword(s):  
Composite Laminates ◽  
Mechanical Performance ◽  
Impact Damage ◽  
Energy Levels ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Low Velocity ◽  
Repeated Impacts ◽  
Structural Parts ◽  
The Impact

In the last years, the spread of composite laminates into the engineering sectors was observed; the main reason lies in higher values of strength/weight and stiffness/weight ratios with respect to conventional materials. Firstly, the attention was focused on fibres reinforced with thermosetting matrix. Then, the necessity to move towards low density and recyclable solutions has implied the development of composites made with thermoplastic matrix. Even if the first application of thermoplastic composites can be found into no structural parts, the replacement of metallic structural parts with such material in areas potentially subjected to impact has become worthy of investigation. Depending on the field of application and on the design geometry, in fact, some components can be subjected to repeated impacts at localized sites either during fabrication, activities of routine maintenance or during service conditions. When composite material was adopted, even though the impact damage associated to the single impact event can be slight, the accumulation of the damage over time may seriously weaken the mechanical performance of the structure. In this overview, the capability of energy absorption of a new composite completely made of thermoplastic material was investigated. This material was able to combine two conflicting requirements: the recyclability and the lightweight. In particular, repeated impacts at low velocity, on self-reinforced laminates made of polypropylene (PP), were conducted by experimental drop dart tests. Repeated impacts up to the perforation or up to 40 times were performed. In the analysis, three different energy levels and three different values of the laminate thicknesses were considered in order to analyse the damage behaviour under various experimental configurations. A visual observation of the impacted specimens was done, in order to evaluate the damage progression. Moreover, the trend of the peak force interchanged between specimen and dart and the evolution of both the absorbed energy and of the bending stiffness with the impacts number were studied. The results pointed out that the maximum load and the stiffness of the specimens tended to grow increasing the number of the repeated impacts. Such trend is opposite compared to the previous results obtained by other researchers using thermosetting composites.

An Enhanced Time-Reversal Method for Impact Damage Monitoring on Plate-Like Structures

2012 ◽  
Vol 525-526 ◽  
pp. 365-368
Author(s):  
Chun Lin Chen ◽  
Yu Long Li ◽  
Fuh Gwo Yuan
Keyword(s):  
Time Reversal ◽  
Composite Structures ◽  
Impact Damage ◽  
High Energy ◽  
Low Velocity ◽  
Energy Impact ◽  
Location Detection ◽  
Focusing Property ◽  
The Impact ◽  
Impact Events

Based on the self-focusing property of time-reversal (T-R) concept, a time focusing parameter was suggested to improve the impact source identification method developed in authors previous work. This paper presents a further study on monitoring relatively high energy impact events which caused induced damage on structures. Numerical verifications for a finite isotropic plate and a composite plate under low velocity impacts are performed to demonstrate the versatility of T-R method for impact location detection with induced plastic deformation and delamination damage on metallic and composite structures respectively. The focusing property of T-R concept was adequately utilized to detect impact/damage location. The results show that impact events with various features can be localized using T-R method by introducing the time focusing parameter. It is suited to monitor serious impact events on plate like structures in practice in future.

scholarly journals Impact Damage Resistance and Post-Impact Tolerance of Optimum Banana-Pseudo-Stem-Fiber-Reinforced Epoxy Sandwich Structures

2020 ◽  
Vol 10 (2) ◽  
pp. 684 ◽  
Author(s):  
Mohamad Zaki Hassan ◽  
S. M. Sapuan ◽  
Zainudin A. Rasid ◽  
Ariff Farhan Mohd Nor ◽  
Rozzeta Dolah ◽  
...  
Keyword(s):  
Composite Structures ◽  
Sandwich Structures ◽  
Impact Damage ◽  
Fiber Composite ◽  
Peak Load ◽  
Weight Ratio ◽  
Synthetic Fiber ◽  
Damage Area ◽  
Banana Fibers ◽  
The Impact

Banana fiber has a high potential for use in fiber composite structures due to its promise as a polymer reinforcement. However, it has poor bonding characteristics with the matrixes due to hydrophobic–hydrophilic incompatibility, inconsistency in blending weight ratio, and fiber length instability. In this study, the optimal conditions for a banana/epoxy composite as determined previously were used to fabricate a sandwich structure where carbon/Kevlar twill plies acted as the skins. The structure was evaluated based on two experimental tests: low-velocity impact and compression after impact (CAI) tests. Here, the synthetic fiber including Kevlar, carbon, and glass sandwich structures were also tested for comparison purposes. In general, the results showed a low peak load and larger damage area in the optimal banana/epoxy structures. The impact damage area, as characterized by the dye penetration, increased with increasing impact energy. The optimal banana composite and synthetic fiber systems were proven to offer a similar residual strength and normalized strength when higher impact energies were applied. Delamination and fracture behavior were dominant in the optimal banana structures subjected to CAI testing. Finally, optimization of the compounding parameters of the optimal banana fibers improved the impact and CAI properties of the structure, making them comparable to those of synthetic sandwich composites.

scholarly journals Characterisation of Impact Damage of Composite Structures Using Wavelet-Based Fusion of Ultrasonic and Optical Images

2014 ◽  
Vol 23 (5) ◽  
pp. 096369351402300
Author(s):  
Andrzej Katunin ◽  
Pawel Kostka
Keyword(s):  
Composite Structures ◽  
Damage Identification ◽  
Impact Damage ◽  
Human Perception ◽  
Laminated Plates ◽  
Low Velocity ◽  
Fusion Algorithm ◽  
Fibre Failure ◽  
Optical Images ◽  
The Impact

This paper presents the novel approach for the impact damage characterisation of composite structures, which is based on fusion of ultrasonic scans and optical images. Both internal (inter-fibre failure, fibre failure, delaminations) and external (scratches and surface cracks) damages occurred in the composite structures during their operation need to be analysed due to their occurrence on both of these levels, especially in the case of impact damages. The presented approach allows for the improvement of the characterisation quality, i.e. the whole damaged area could be detected and localized. In order to assure the proper damage identification the wavelet-based fusion with application of appropriate wavelets and parameters of a fusion algorithm was used, which allows for distinction of different types of damages and overall improvement of the resulted image with respect to the human perception capability. The approach was validated experimentally on the glass-epoxy laminated plates after the low-velocity impacts. Representative cases of damaged structure were presented and analysed.

scholarly journals Assessment of low-velocity impact damage in composites by the measure of second-harmonic guided waves with the phase-reversal approach

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041988107 ◽  
Author(s):  
Weibin Li ◽  
Chang Jiang ◽  
Xinlin Qing ◽  
Liangbing Liu ◽  
Mingxi Deng
Keyword(s):  
Guided Waves ◽  
Second Harmonic ◽  
Impact Damage ◽  
Guided Wave ◽  
Second Order ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Phase Reversal ◽  
The Impact

Structural strength and integrity of composites can be considerably affected by the low-velocity impact damage due to the unique characteristics of composites, such as layering bonded by adhesive and the weakness to impact. For such damage, there is an urgent need to develop advanced nondestructive testing approaches. Despite the fact that the second harmonics could provide information sensitive to the structural health condition, the diminutive amplitude of the measured second-order harmonic guided wave still limits the applications of the second-harmonic generation–based nonlinear guided wave approach. Herein, laminated composites suffered from low-velocity impact are characterized by use of nonlinear guided waves. An enhancement in the signal-to-noise ratio for the measure of second harmonics is achieved by a phase-reversal method. Results obtained indicate a monotonic correlation between the impact-induced damage in composites and the relative acoustic nonlinear indicator of guided waves. The experimental finding in this study shows that the measure of second-order harmonic guided waves with a phase-reversal method can be a promising indicator to impact damage rendering in an improved and reliable manner.

AN ASSESSMENT OF STIFFENED COMPOSITE FUSELAGE PANELS BASED ON THE ROBUSTNESS PARAMETER

2010 ◽  
Vol 10 (04) ◽  
pp. 717-736
Author(s):  
MERRILL C. W. LEE ◽  
ZOLTAN MIKULIK ◽  
DONALD W. KELLY ◽  
RODNEY S. THOMSON
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Design Guidelines ◽  
Stochastic Algorithms ◽  
Buckling Modes ◽  
Statistical Variations ◽  
Stiffened Composite Panels ◽  
Final Design ◽  
Input Variables ◽  
The Impact

The European Commission 6th Framework Project COCOMAT was a four-and-a-half-year project (2004 to mid-2008) aimed at exploiting the large reserve of strength in composite structures through more accurate prediction of collapse. In the experimental work packages, significant statistical variations in buckling behaviour and ultimate loading were encountered. During the experiments for the COCOMAT project, it was recognised that there was a gap in knowledge about the effect of initial defects and variations in the input variables of both the experimental and simulated panels. The effect of the defects and variations in the experimental panel resulted in some failure modes that were not predicted with the finite element modelling. This led to the development of stochastic algorithms to relate variations in boundary conditions, material properties and geometries to the variation in buckling modes and compression loads up to the first failure. This paper shows the development of a stochastic methodology to identify the impact of variation in input parameters on the response of stiffened composite panels and the development of a robust index to support the evaluation of panel designs. The stochastic analysis included the generation of metamodels that allow quantification of the impact that the inputs have on the response using two first order variables, influence and sensitivity. These variables were then used to derive the robust indices to quantify the response of two COCOMAT panels that were experimentally tested, including the response of the panels to simulated damage. The robust indices that are shown in this paper are functions of the robustness parameter which has been recommended in the final Design Guidelines for the COCOMAT project to measure the effects of scatter found in postbuckling loads.

scholarly journals Low-speed impact damage analysis of aviation composite material structure

2021 ◽  
Vol 260 ◽  
pp. 03021
Author(s):  
Jun He ◽  
Meng Cao ◽  
Zhishu Wang ◽  
Fanglin Cong
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Composite Material ◽  
Composite Structures ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Material Structure ◽  
Damage Analysis ◽  
Low Speed ◽  
The Impact

Although the carbon fiber reinforced composite material has high specific strength and stiffness, design-versatility, anti-corrosion and other excellent features, but the impact resistance of composite structures is poor. Therefore, the composite laminates low-speed damage analysis has important significance. Based on a three-dimensional analysis theory of cumulative damage, using the commercial finite element analysis software ABAQUS to establish laminates subjected to low velocity impact finite element model. according to the numerical results and the consistency of the test results, shows that the used model of the article is reasonable and accurate, and the numerical simulation method is verified to be feasible. Finally, through the numerical simulation of process of laminated plates low speed impact damage, the damage characteristics and damage mechanism of the laminates at different times are analyzed, and the forming reasons and expanding rules of the main damage forms of fiber damage and matrix damage are revealed.

scholarly journals 3D Modelling of the Scattering of the Fundamental Anti-Symmetric Lamb Mode (A0) Propagating within a Point-Impacted Transverse-Isotropic Composite Plate

2021 ◽  
Vol 11 (16) ◽  
pp. 7276
Author(s):  
Dilbag Singh ◽  
Mourad Bentahar ◽  
Charfeddine Mechri ◽  
Rachid El Guerjouma
Keyword(s):  
Composite Plate ◽  
Impact Damage ◽  
Elastic Stiffness ◽  
Wave Mode ◽  
Guided Wave ◽  
Domain Model ◽  
Isotropic Composite ◽  
Damaged Zone ◽  
The Impact ◽  
Lamb Mode

The present paper deals with an effort to model impact damage in 3D-FE simulation. In this work, we studied the scattering behavior of an incident A0 guided wave mode propagating towards an impacted damaged zone created within a quasi-isotropic composite plate. Besides, barely visible impact damage of the desired energy was created and imaged using ultrasonic bulk waves in order to measure the size of the damage. The 3D-FE frequency domain model is then used to simulate the scattering of an incident guided wave at a frequency below an A1 cut-off with a wavelength comparable to the size of the damaged zone. The damage inside the plate is modeled as a conical-shaped geometry with decayed elastic stiffness properties. The model was first validated by comparing the directivity of the scattered fields for the A0 Lamb mode predicted numerically with the experimental measurements. The modeling of the impact zone with conical-shape geometry showed that the scattering directivity of the displacement field depends significantly on the size (depth and width) of the conical damage created during the point-impact of the composite with potential applications allowing the determination of the geometric characteristics of the impacted areas.

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