Q1. What are the contributions in this paper?
In this paper, a Flat-Bottomed Hole ( FBH ) defect is modeled by finite el14 ement method in a polymethylmethacrylate ( PMMA ) structure.
Automated extraction of local defect resonance using the principal component analysis in lock-in ultrasonic vibrothermography
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TLDR
In this paper, a flat-bottomed hole (FBH) defect is modeled by finite element method in a polymethylmethacrylate (PMMA) structure and the desired information from this defect is retrieved by its local defect resonance (LDR) frequency which is estimated through a Principal Component Analysis (PCA).About:
This article is published in Infrared Physics & Technology.The article was published on 2020-03-01 and is currently open access. It has received 10 citations till now. The article focuses on the topics: Sine wave & Nondestructive testing.read more
Figures
Figure 1: Geometry of the simulated PMMA model, showing the position of both an FBH defect and a piezoelectric actuator. 
Figure 5: PCA images of different modes showing the consistency of the eigenvectors with the results reported in Fig. 4. 
Table 1: Material properties of the PMMA plate in the FEM analysis 
Figure 4: The magnitude of eigenvalues in a descending order showing quick convergence to zero. 
Figure 7: Schematic of the lock-in process applied to the frames obtained by an IR camera. 
Table 5: Calculated defective area for the FBH defect based on the Otsu’s thresholding shown in Fig.11.
Citations
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Journal ArticleDOI
Polarimetric data-based model for tissue recognition
Carla Rodríguez,Albert Van Eeckhout,Laia Ferrer,Enrique Garcia-Caurel,Emilio González-Arnay,Juan Campos,Angel Lizana +6 more
TL;DR: In this paper, the potential of a predictive optical model method for tissue recognition, based on the statistical analysis of different polarimetric indicators that retrieve complete polarIMetric information (selective absorption, retardance and depolarization) of samples.
Journal ArticleDOI
New Learning Approach for Unsupervised Neural Networks Model with Application to Agriculture Field
TL;DR: An accurate and lower cost hybrid machine learning algorithm based on a combination of Kohonen-Self Organizing Map (SOM) and Gram-Schmidt (GSHM) algorithm was proposed, to enhance the crop yield prediction and to increase the agricultural production.
Journal ArticleDOI
Surface crack detection by using vibrothermography technique
TL;DR: In this article , the authors aim to optimise the vibration frequency that produces the highest temperature difference between crack location and non-defect location, based on thermoelastic damping analysis, and the analytical frequencies were varied between 10 Hz and 100 kHz.
Journal ArticleDOI
Detection and quantification of artificial delaminations in CFRP composites using ultrasonic thermography
TL;DR: In this article , the authors performed an experimental investigation on delamination detection in carbon fiber reinforced polymer (CFRP) plates using ultrasonic thermography with an ultrasonic transducer, and the results indicated that the first and second principal components (PC1 and PC2) of PCA provided the highest SNR and the largest number of delaminations detected, respectively.
Journal ArticleDOI
Characterization of EMAT Guided Wave Reflectivity on Welded Structures for Use in Ranging
TL;DR: In this paper , the suitability of various EMAT generated guided wave modes when reflecting from butt welds for the purpose of choosing a low frequency mode suitable for accurate ranging was investigated. Butts are tested in 10mm mild steel plate in experiment and simulation, and the determination of the wave mode best suited for weld ranging by means of comparison of the reflection coefficients.
References
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Journal ArticleDOI
Principal component analysis: a review and recent developments
TL;DR: The basic ideas of PCA are introduced, discussing what it can and cannot do, and some variants of the technique have been developed that are tailored to various different data types and structures.
Book
Theory of Vibration with Applications
TL;DR: In this paper, a new chapter on computational methods that present the basic principles on which most modern computer programs are developed is presented, which introduces an example on rotor balancing and expands on the section on shock spectrum and isolation.
Journal Article
Practical Approaches to Principal Component Analysis in the Presence of Missing Values
Alexander Ilin,Tapani Raiko +1 more
TL;DR: A probabilistic formulation of PCA provides a good foundation for handling missing values, and formulas for doing that are provided, and a novel fast algorithm is introduced and extended to variational Bayesian learning.
Journal ArticleDOI
Numerical modeling of elastic wave propagation and scattering with EFIT — elastodynamic finite integration technique
TL;DR: In this paper, the basic equations of EFIT, the Elastodynamic Finite Integration Technique, are formulated for anisotropic inhomogeneous media in 3D, and the discrete equations on a staggered grid resulting in a unique way to discretize material parameters, and evaluate stability conditions and consistency for isotropic homogeneous unbounded media.