scholarly journals Comparative Evaluation of a High Operating Temperature Midwave Infrared Detector for Automated Non-Destructive Inspection of Composite Damage

2021 ◽  
Keyword(s):  
Composite Structures ◽  
High Performance ◽  
Operating Temperature ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Flat Bottom ◽  
High Operating Temperature ◽  
Uncooled Microbolometer ◽  
Midwave Infrared

Abstract. A new high operating temperature (HOT) midwave infrared (MWIR) imaging core is experimentally evaluated for use in automated inspection of composite impact damage by line scan thermography (LST). This evaluation is undertaken as part of a broader effort to develop an autonomous inspection capability for aerospace composite structures, deployable by ground and aerial robotic systems. The performance of the HOT MWIR core is assessed against a high-performance cooled photon-detector camera, an uncooled microbolometer core and an uncooled microbolometer camera, on two carbon epoxy laminate test specimens: one containing flat-bottom-hole synthetic defects and the other barely visible impact damage (BVID) introduced by controlled low-velocity impact. These test panels are scanned using a 3-axis robotic LST apparatus, at speeds of 25 and 100 mm/s. The HOT MWIR core is shown to match the detection performance of the cooled camera, and to significantly outperform both microbolometers. The high performance of this core combined with its relatively low mass, size and power consumption offers an encouraging basis for the development of a drone-deployable LST inspection capability.

Real-time monitoring of low-velocity impact damage for composite structures with the omnidirection carbon nanotubes’ buckypaper sensors

2018 ◽  
Vol 18 (2) ◽  
pp. 454-465 ◽  
Author(s):  
Shaowei Lu ◽  
Kai Du ◽  
Xiaoqiang Wang ◽  
Caijiao Tian ◽  
Duo Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Composite Structures ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Sensor Technology ◽  
Gauge Factor ◽  
Low Velocity ◽  
Repeated Impact ◽  
Velocity Impact ◽  
The Impact

A novel, omnidirectional, nanomaterial-based sensor technology which can provide wide area damage detection of composite structures was proposed in this work. The behaviors of the buckypaper sensors subjected to both tensile and low-velocity impact were investigated. The experimental results showed that the rectangle buckypaper sensor has a large range of sensing coefficients from 21.40 to 35.83 at different directions under tensile. However, the circular buckypaper sensor has a steady sensing coefficient of about 155.63. Thus, the circular buckypaper sensor as a kind of omnidirectional sensor was chosen to monitor the impact damage. The low-velocity impact damage of composite structures is characterized by the gauge factor of omnidirectional buckypaper sensors and the results of C-scanning. Omnidirectional buckypaper sensors’ electrical resistance increases with repeated impact loading; composite structure elastic deformation and damage evolution can be identified from resistance change. Experiment results show that structure monitoring based on the omnidirectional buckypaper sensor not only can detect small barely visible impact damage flaws and the damage evaluation of composite structures subjected to impact but also can determine the location of low-velocity impact damage through the analysis of results. Through comparison with C-scan, the results have preliminarily demonstrated that the omnidirectional carbon nanotubes’ buckypaper sensor can serve as an efficient tool for sensing the evolution of impact damage as well as serve structural health monitoring of composite structures.

A Damage Analysis on the Composite Plate Subjected to Low Velocity Impact

2006 ◽  
Vol 306-308 ◽  
pp. 285-290
Author(s):  
Young Shin Lee ◽  
Hyun Soo Kim ◽  
Young Jin Choi ◽  
Jae Hoon Kim
Keyword(s):  
Composite Structures ◽  
Composite Plate ◽  
Impact Damage ◽  
Laminated Composite ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Failure Behavior ◽  
Low Velocity ◽  
Velocity Impact ◽  
Delamination Failure

The laminated composite structures applied to the wing and the speed brake of an aircraft or the turbine blade of a compressor. These structures may be impacted by birds and hails during operation. They may also be impacted by drop of a tool during manufacture or repair. Unlike high velocity impact damage, which can be easily found by the naked eye, the damage due to low velocity impact may be difficult to detect. Damage which is not detected may cause failure of a structure and result in damage propagation. Growth of damage means reduction of stiffness on the structure. So, exact prediction of damage caused by a low velocity impact is very important in order to guard against sudden failure of the structure. In this study, modified delamination failure criterion has suggested in order to predict the failure behavior of a composite plate subjected to low-velocity impact. The criterion includes the assumption which is matrix cracking mode causes delamination failure. Predicted damage using supposed delamination criterion is similar to experiment results.

The response of composite structures with pre-stress subject to low velocity impact damage

2004 ◽  
Vol 66 (1-4) ◽  
pp. 685-698 ◽  
Author(s):  
B. Whittingham ◽  
I.H. Marshall ◽  
T. Mitrevski ◽  
R. Jones
Keyword(s):  
Composite Structures ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact

Structural Health Monitoring of Composite Structures Using Guided Lamb Waves

2006 ◽  
Vol 321-323 ◽  
pp. 759-764 ◽  
Author(s):  
Krishnan Balasubramaniam ◽  
B.V. Soma Sekhar ◽  
J. Vishnu Vardan ◽  
C.V. Krishnamurthy
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Composite Structures ◽  
Lamb Waves ◽  
Impact Damage ◽  
Composite Plates ◽  
Structural Features ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Structural Health

Structural Health Monitoring (SHM) of aircrafts is of great relevance in the present age aircraft industry. The present study demonstrates three techniques that have the potential for the SHM of multi-layered composite structures. The first technique is based on multi-transmitter-multireceiver (MTMR) technique with tomographic methods used for data reconstruction. In the MTMR, the possibility of SHM using algebraic reconstruction techniques (ART) for tomographic imaging with Lamb wave data measured in realistic materials is examined. Defects (through holes and low velocity impact delaminations) were synthetic and have been chosen to simulate impact damage in composite plates. The second technique is a single-transmitter-multi-receiver (STMR) technique that is more compact and uses reconstruction techniques that are analogous to synthetic aperture techniques. The reconstruction algorithm uses summation of the phase shifted signals to image the location of defects, portions of the plate edges, and any reflectors from inherent structural features of the component. The third technique involves a linear array of sensors across a stiffener for the detection of disbanded regions.

Damage Localization in a Stiffened Composite Panel Using a Lamb Wave Based Tomography Approach

2011 ◽  
Author(s):  
Anthony J. Vizzini ◽  
Yingtao Liu ◽  
Aditi Chattopadhyay
Keyword(s):  
Composite Structures ◽  
Impact Damage ◽  
Matching Pursuit ◽  
Low Velocity Impact ◽  
Composite Panel ◽  
Low Velocity ◽  
Stiffened Panels ◽  
Time Frequency ◽  
Matching Pursuit Decomposition ◽  
High Level

In structural health monitoring (SHM) of aerospace components, such as stiffened panels, detection and localization of damage is an important issue. This paper presents a methodology for determining the existence and location of low velocity impact damage in a stiffened composite panel. Using a matching pursuit decomposition algorithm, converted modes due to damage were extracted in the time-frequency domain. The energy of the converted mode was then used in conjunction with a probabilistic tomography approach that was able to localize the damage with a high level of accuracy. The results obtained confirm the ability of this approach to detect and localize damage in complex composite structures.

Kernel Feature Space Based Low Velocity Impact Monitoring

2012 ◽  
Author(s):  
Yingtao Liu ◽  
Masoud Yekani Fard ◽  
Aditi Chattopadhyay
Keyword(s):  
Composite Structures ◽  
Impact Damage ◽  
Damage Index ◽  
Low Velocity Impact ◽  
Kernel Principal Component Analysis ◽  
Monitoring Methods ◽  
Low Velocity ◽  
Velocity Impact ◽  
Statistical Feature ◽  
The Impact

Impact damage has been identified as a critical form of defect that constantly threatens the reliability of composite structures, such as those used in aircrafts and naval vessels. Low energy impacts can introduce barely visible damage and cause structural degradation. Therefore, efficient structural health monitoring methods, which can accurately detect, quantify, and localize impact damage in complex composite structures, are required. In this paper a novel damage detection methodology is demonstrated for monitoring and quantifying the impact damage propagation. Statistical feature matrices, composed of features extracted from the time and frequency domains, are developed. Kernel Principal Component Analysis (KPCA) is used to compress and classify the statistical feature matrices. Compared with traditional PCA algorithm, KPCA method shows better feature clustering and damage quantification capabilities. A new damage index, formulated using Mahalanobis distance, is defined to quantify impact damage. The developed methodology has been validated using low velocity impact experiments with a sandwich composite wing.

scholarly journals A model of low-velocity impact damage assessment of laminated composite structures

2018 ◽  
Vol 188 ◽  
pp. 01012 ◽  
Author(s):  
Konstantinos P. Stamoulis ◽  
Stylianos K. Georgantzinos ◽  
Georgios I. Giannopoulos
Keyword(s):  
Composite Structures ◽  
Mechanical Performance ◽  
Impact Damage ◽  
Experimental Testing ◽  
Laminated Composite ◽  
Element Model ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Initiation ◽  
Laminated Composite Structures

Laminated composites have important applications in modern aeronautical structures due to their extraordinary mechanical and environmental behaviour. Nevertheless, aircraft composite structures are highly vulnerable to impact damage, either by low-velocity sources during maintenance or high-velocity sources during in-flight events. Even barely visible impact damage induced by low-velocity loading, substantially reduces the residual mechanical performance and the safe-service life of the composites structures. Despite the extensive research already carried out, impact damage of laminated composite structures is still not well understood and it is an area of on-going research. Numerical modelling is considered as the most efficient tool as compared to the expensive and time-consuming experimental testing. In this paper, a finite element model based on explicit dynamics formulations is adopted. Hashin criterion is applied to predict the intra-laminar damage initiation and evolution. The numerical analysis is performed using the ABAQUS® programme. The employed modelling approach is validated using numerical results found in the literature and the presented results show an acceptable correlation to the available literature data. It is demonstrated that the presented model is able to capture force-time response as well as damage evolution map for a range of impact energies.

scholarly journals Classification of Cracks in Composite Structures Subjected to Low-Velocity Impact Using Distribution-Based Segmentation and Wavelet Analysis of X-ray Tomograms

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8342
Author(s):  
Angelika Wronkowicz-Katunin ◽  
Andrzej Katunin ◽  
Marko Nagode ◽  
Jernej Klemenc
Keyword(s):  
Composite Structures ◽  
Structural Damage ◽  
Residual Life ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Fracture Mechanisms ◽  
Low Velocity ◽  
Velocity Impact ◽  
X Ray ◽  
X Ray Computed

The problem of characterizing the structural residual life is one of the most challenging issues of the damage tolerance concept currently applied in modern aviation. Considering the complexity of the internal architecture of composite structures widely applied for aircraft components nowadays, as well as the additional complexity related to the appearance of barely visible impact damage, prediction of the structural residual life is a demanding task. In this paper, the authors proposed a method based on detection of structural damage after low-velocity impact loading and its classification with respect to types of acting stress on constituents of composite structures using the developed processing algorithm based on segmentation of 3D X-ray computed tomograms using the rebmix package, real-oriented dual-tree wavelet transform and supporting image processing procedures. The presented algorithm allowed for accurate distinguishing of defined types of damage from X-ray computed tomograms with strong robustness to noise and measurement artifacts. The processing was performed on experimental data obtained from X-ray computed tomography of a composite structure with barely visible impact damage, which allowed better understanding of fracture mechanisms in such conditions. The gained knowledge will allow for a more accurate simulation of structural damage in composite structures, which will provide higher accuracy in predicting structural residual life.

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