Nico F Declercq

Nico F Declercq
Georgia Institute of Technology | GT · School of Mechanical Engineering

PhD in Engineering Physics

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195
Publications
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1,230
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Publications

Publications (195)
Article
The inspection of sizeable plate-based metal structures such as storage tanks or marine vessel hulls is a significant stake in the industry, which necessitates reliable and time-efficient solutions. Although Lamb waves have been identified as a promising solution for long-range non-destructive testing, and despite the substantial progress made in a...
Book
Full-text available
This is a 1384 pages book on the history of the Desclergue family of Montblanc in Tarragona Spain.
Book
This book, consisting of 67 chapters, spread over ten parts and a foreword section, covers the following topics. Part I on page 5 is a prelude and introduces the reader to the world of Heraldry, the Town and the Duchy of Montblanc in Spain and Onomastics. Finally, it provides a brief history to understand the book's chronological context better. Pa...
Article
We carry out a nondestructive study of injection-mold weld lines in an acrylonitrile butadiene styrene (ABS) thermoplastic electrical receptacle plate. Terahertz techniques show morphological features at the weld lines and reveal terahertz birefringence properties localized about the welds, indicating frozen-in molecular orientation and stress prox...
Chapter
In this work (This work is part of the BugWright2 project. This project is supported by the European Commission under grant agreement 871260 - BugWright2.), we propose a method based on a particle filter for the localization of an industrial robot on a large metal structure that leverages first-order reflections of acoustic waves on a metal plate e...
Article
We present a novel FastSLAM approach for a robotic system inspecting structures made of large metal plates. By taking advantage of the reflections of ultrasonic guided waves on the plate boundaries, it is possible to recover, with enough precision, both the plate shape and the robot trajectory. Contrary to our previous work, this approach takes int...
Article
Full-text available
Analysis based on the determination of the multifactorial non-linearity parameter (β) is a promising non-destructive investigation and testing technique. The contribution of temperature variations on the non-linear coefficient is known to be lower than that of hydrostatic pressure changes. We investigated the effect of temperature on the non-linear...
Article
The present experimental work investigates the response of woven glass fabric reinforced polyamide 6.6/6 subjected to drop weight impact loading. The main objective is the development and the introduction of a new experimental procedure/approach, based on different complementary detection techniques, that aims at investigating the damage induced by...
Article
Scanning acoustic microscopy (SAM) is used to characterize welds in a trade thermoplastic polymer (ABS) manufactured by injection-molding, particularly at the locations of weld-lines known to form as unavoidable significant defects. Acoustic micrographs obtained at 420 MHz clearly resolve the weld lines with morphological deformations and microelas...
Article
Full-text available
Scanning acoustic microscopy in the gigahertz regime (GHz-SAM) has long been a versatile and complementary micro and nanoscopic imaging and analysis tool. Nevertheless, it remained obscured to some extent, compared to its counterparts, such as atomic force microscopy (AFM), despite its unique capability of subsurface imaging and analysis. Some curr...
Book
Due to travel restrictions after the CoVid-19 pandemic, the dates have been postponed to a later time in Summer 2021. A final decision about the format of the symposium is expected by late March.
Conference Paper
The present experimental works study the response of a polyamide 6.6/ 6 reinforced with woven glass fibers to drop weight solicitations. Several tests were carried out under numerous impact energies. A quantitative along with a qualitative study of the induced damage are the main objectives of this study. Different non-destructive evaluation (NDE)...
Article
Full-text available
Acoustic Wood anomaly is a pulsed ultrasound phenomenon in which sharp spectral anomalies such as tips or dips or both occur in the spectrum of a pulse reflected from or transmitted through a periodically corrugated interface for normal incidence. To date only surface acoustic waves generated on periodic interface through diffraction mechanism have...
Article
Full-text available
The consequences of a four-point bending test, up to 12 mm, are examined by emitting 1 MHz ultrasonic guided waves in woven carbon fiber reinforced polymer specimens, using coda wave interferometry (CWI), revealing a potential use for nondestructive evaluation. It is known that CWI is more sensitive to realistic damage than the conventional method...
Article
Full-text available
Purpose: To describe the application of scanning acoustic microscopy in the GHz-range (GHz-SAM) for qualitative imaging and quantitative characterization of the micromechanical properties of the Descemet's membrane and endothelial cells of cornea tissue. Methods: Investigated were samples of a normal tissue and a tissue with Fuchs' endothelial d...
Article
Full-text available
Fa un temps, en Nico F. Declercq, belga establert als Estats Units, es va posar en contacte amb el Centre d'Estudis de la Conca de Barberà a fi de completar una recerca genealògica que estava portant a terme. De seguida, el secretari de l'entitat, Josep-Pau Jàvega, i el president, Josep M. Grau li van enviar tot el que s'havia publicat sobre la fam...
Article
A device generating low-frequency and low-intensity ultrasound waves was used for mitigating biofilm accumulation and scaling. Two systems were tested: a lab-scale plate heat exchanger operated with continuously recycled water and a continually fed flow-through drinking water pilot used for mimicking water circulation in pipes. Initial deposition o...
Article
An investigation of a polyamide 6.6/6 composite reinforced with woven glass fibers is described with a focus on its response to fatigue solicitations. The main purpose is to elaborate a quantitative and a qualitative study of the induced damage as well as its detectability. To do so, several nondestructive testing methods were used. The different d...
Article
Polarization-sensitive terahertz imaging is applied to characterize subsurface damage in woven carbon fiber-reinforced composite laminates in this study. Terahertz subsurface spectral imaging based on terahertz deconvolution is tailored and applied to detect, in a nondestructive fashion, the subsurface damage within the first ply of the laminate ca...
Article
Full-text available
The paper proposes a new experimental methodology, based on ultrasonic measurements, that aims at evaluating the anisotropic damage in woven semi-crystalline polymer composites through new damage indicators. Due to their microstructure, woven composite materials are characterized by an anisotropic evolution of damage induced by different damage mec...
Article
The influence of liquid-flow up to 7 mm/s is examined on transmission spectra of phononic crystals, revealing a potential use for slow liquid-flow measurement techniques. It is known that transmission of ultrasound through a phononic crystal is determined by its periodicity and depends on the material characteristics of the crystal's constituents....
Conference Paper
Due to their specific elastic properties (high stiffness to mass ratio), regular microstructure materials (architectural materials), are widely used in industry. This work deals with nondestructive evaluation of a 3D bi-material structure made of an architectural ABS polymer embedded in an Epoxy resin. The difficulty of applying ultrasonic techniqu...
Article
A discussion of nondestructive techniques is presented for the investigation of complex media, with a focus on composite samples. Traditionally, one applies ultrasonic C-scans, or polar scans, which are easy to implement and to interpret. However, in many realistic cases, it is important to use more sophisticated approaches as C-scans often do not...
Article
This work was done on woven glass-fiber fabric reinforced composite samples. Those materials exhibit a complex anisotropic evolution of defects induced by several damage mechanisms. In order to non-destructively evaluate the damage accumulation within this material, a methodology based on the measurement of the complete stiffness tensor is consider...
Article
Full-text available
This paper presents an overview and description of the approach to be used to investigate the behavior and the defect sensitivity of various ultrasonic guided wave (UGW) modes propagating specifically in composite cylindrical vessels in the framework of the safety of hydrogen energy transportation such as hydrogen-powered aircrafts. These structure...
Conference Paper
Un composite polyamide 66/6 renforcé par un tissu à armature sergée de 2,2 en fibres de verres a été étudié par une méthode ultrasonore avancée. Les mécanismes d’endommagement de ce type de matériau dépendent de la nature de sollicitation et de l’architecture du renfort, en particulier de l’orientation des fibres. Dans ce travail, une sollicitation...
Article
The difficulty of applying ultrasonic techniques to bi-material structures lies in the fact that different phenomena coexist, such as the non-lineareffects caused by the adhesion properties between matrix-fibers and the diffractioneffect caused by the periodicity of those structures. This work deals with the study of the combined effect of non-line...
Article
Full-text available
An analytical and experimental study of the pulsed ultrasonic comb filtering effect is presented in this work intending to provide a fundamental tool for data analysis and phenomenon understanding in pulsed ultrasonics. The basic types of comb filter, feedforward and feedback filters, are numerically simulated and demonstrated. The characteristic f...
Article
Full-text available
In acoustics, the term Wood anomaly, in analogy to the Wood anomaly in optics, has so far referred to the anomalies observed in the specular reflection spectra of acoustic waves perpendicularly incident on periodic surfaces. Inspired by the pioneering work of Jungman et al. on the study of the transmission field of a solid-fluid periodic interface,...
Article
Full-text available
The dispersion of the phase velocities of the Scholte-Stoneley waves on a periodically corrugated interface is experimentally investigated and presented. The Scholte-Stoneley waves are generated through diffraction of the incident bulk longitudinal waves in water on a solid-fluid (brass-water) interface with one-dimensional grooves. The diffraction...
Article
The application of ultrasonic guided waves (UGW) to the field of preventive maintenance of composite structures is in continuous increase. Today, UGW is taking an important economical place, especially in the fields of transport and nuclear technology, where the safety of individuals is of higher importance than financial cost.
Article
Abstract: The presented experimental work describes the nondestructive damage examination of polymer-matrix composites using acoustic methods under the consideration of nonlinear effects. The aim is to analyze these nonlinear effects in order to provide a quantification of the nonlinear acoustic transmission which is related to the damage state and...
Article
Full-text available
When a wideband sound beam is incident onto a periodically corrugated surface, a series of diffraction related phenomena can occur. In this work, we report the observation of a secondary diffraction, which is different from those previously investigated. The search of the physical origin of this newly observed diffraction leads to the discovery of...
Article
Full-text available
Terahertz imaging is applied to characterize a hybrid fiber-reinforced composite laminate subject to low-velocity impact in this study. The hybrid fiber-reinforced composite laminate comprises unidirectional glass/epoxy and carbon/epoxy plies with a cross-ply stack pattern. Both impact-induced intra- and inter-laminar damages are successfully detec...
Article
Periodic structures are very common in both scientific investigations and engineering applications. The geometry of the periodic structure is important for its designed functionality. Although the techniques such as optical and electron microscopy are capable of measuring the periodicity of microscale periodically-corrugated structures, they cannot...
Article
Full-text available
A brief summary of the 2015 International Congress on Ultrasonics is presented. The 2015 ICU has taken place in Metz, France, at the Arsenal and was hosted by Georgia Tech Lorraine in collaboration with the French Acoustical Society. The congress hosted a record number of 700 participants. The report focuses on the awards presented during the congr...
Article
Full-text available
When a sound beam is incident onto a periodically corrugated surface, diffraction of the incident sound will be generated. The major diffraction phenomenon, which can be well explained by the classical grating equation, can be easily observed and has been intensively studied. In this work, we report an observation of diffracted waves whose intensit...
Data
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Article
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Glass fiber-reinforced composite laminates in polyetherimide resin have been studied via terahertz imaging and ultrasonic C-scans. The forced delamination is created by inserting Teflon film between various layers inside the samples prior to consolidating the laminates. Using reflective pulsed terahertz imaging, we find high-resolution, low-artifac...
Article
Acousto-Optic Bragg Imaging is a technique that uses the interaction of light with ultrasound to optically image obstructions in acoustical fields. Existing reports of Acousto-Optic Bragg Imaging based on transmission of acoustic fields through obstructions exhibit strong acoustic impedance mismatches manifested by poor image quality and missing de...
Article
Full-text available
In the spectrum of a broadband wave reflected from a periodically corrugated surface, spectral anomalies have been observed earlier and identified as acoustic Wood anomalies. A thorough investigation of the physical origin of the acoustic Wood anomaly is made through an experimental investigation and an examination of the existing theories. The exi...
Conference Paper
Conference code: 118637, Export Date: 2 August 2016, References: Amenabar, I., Lopez, F., Mendikute, A., In introductory review to thz non-destructive testing of composite mater (2013) Journal of Infrared, Millimeter, and Terahertz Waves, 34, pp. 152-169;
Article
Full-text available
The objective of this study is to determine the thickness of ice on lakes and canals by analyzing the sound spectrum generated by dispersion of Lamb type waves propagating in ice. In winters when the lakes and canals freeze, it is important to know the thickness of the ice layer before setting foot on it. When a stone is thrown on the ice layer, a...
Conference Paper
Full-text available
This paper reflects the contents of the plenary talk given by Nico Felicien Declercq. “Ultrasonic Imaging of materials” covers a wide technological area with main purpose to look at and to peek inside materials. In an ideal world one would manage to examine materials like a clairvoyant. Fortunately this is impossible hence nature has offered suffic...
Article
Full-text available
The possibility of surface wave generation by diffraction of pressure waves on deeply corrugated one-dimensional phononic crystal gratings is studied both theoretically and experimentally. Generation of leaky surface waves, indeed, is generally invoked in the explanation of the beam displacement effect that can be observed upon reflection on a shal...
Article
Scholte-Stoneley wave propagation on a dihedral and more precisely the diffraction effects occurring at the corners, has since long been of high importance for nondestructive testing of materials and structures. Experimental investigations have been reported in the past. Simulations based on radiation mode theory have been published before, explain...
Article
Full-text available
Acousto-optic Bragg imaging is a technique that uses the interaction of light with ultrasound to optically image obstructions in acoustical fields. Existing reports of acousto-optic Bragg imaging based on transmission of acoustic fields through obstructions exhibit strong acoustic impedance mismatches manifested by poor image quality and missing de...
Article
Full-text available
A diffraction grating is a spatial filter causing sound waves or optical waves to reflect in directions determined by the frequency of the waves and the period of the grating. The classical grating equation is the governing principle that has successfully described the diffraction phenomena caused by gratings. However, in this work, we show experim...
Article
Full-text available
With the growing interest in phononic crystals for al kinds of applications a deeper understanding of the interaction of sound with such structures is not only of interest while sound is passing through or is stopped by the crystal but also when externally applied sound fields strike a crystal and diff ract upon it. To study a fundamental feature r...
Conference Paper
Conference code: 117181, Export Date: 2 August 2016, References: Wood, R.W., On a remarkable case of uneven distribution of light in a diffracton grating spectrum (1902) Philos. Mag, 4, p. 369;
Article
Full-text available
Acoustic microscopy is a well established technique as far as smooth surfaces are concerned. Traditionally V(z) curves are obtained from which, through surface wave generation, important features concerning elasticity and related properties can be extracted. More recently, high resolution imaging based on acoustic microscopy has appeared. In this s...
Article
The notion of "Wood anomaly" in diffraction spectra in acoustics has been mostly investigated in normal reflection fields obtained from periodically corrugated interfaces between a solid and a liquid. In this work, the phenomenon is investigated both in transmission field as well as in reflection, both normal and onblique. Experiments are performed...
Article
When a bounded beam is incident on an immersed plate Lamb waves or Rayleigh waves can be generated. Because the amplitude of a bounded beam is not constant along its wave front, a specific beam profile is formed that influences the local efficiency of energy conversion of incident sound into Lamb waves or Rayleigh waves. Understanding this phenomen...
Article
This paper suggests a method for high-sensitivity damage detection. The method is based on pitch-catch measurements of Lamb waves combined with a baseline subtraction technique in the frequency-wavenumber domain. Small amplitude converted modes, generated during the interaction of propagating waves with damage, can thus be detected with minimal a p...
Article
Full-text available
We consider an arbitrary periodic corrugated surface of a semi-infinite elastic solid that is immersed in a fluid, forming a one-dimensional phononic crystal. We study the existence and the polarization of guided waves that propagate along the interface. A coupled elastic-acoustic variational model is devised to obtain the dispersion of guided wave...
Article
Full-text available
This short communication aims to compare the Debye series with a modal series for the case of the propagation of a bounded beam in an embedded waveguide. The calculation can be achieved through several methods. These methods are described briefly and the most preponderant references are given. The Modal Expansion Method which is among these method...
Article
Full-text available
The objective of this study is to determine the thickness of Ice by analyzing the sound spectrum generated by dispersion of lamb waves propagating in ice. In winters when the lakes and rivers freeze, it is important to know the thickness of the ice layer before one intends to walk on it. When we throw a stone on the ice layer, we can hear a fluting...
Article
Full-text available
When performing a Fourier transform on the reflection from a periodically corrugated surface for a normally incident beam the reflection spectrum is obtained. Steep dips have been observed from such reflection spectrum and are commonly called Wood anomaly. Because the frequencies at which Wood anomalies appears coincide with the frequencies where s...
Article
Many structures in civil engineering notably bridges and nuclear power plants must be regularly, strictly, and carefully tested to avoid any human or environmental catastrophe. Among the NDT techniques, which can be applied, ultrasonic guided waves are a good candidate to monitor bars and cables. However, its multimodal and dispersive behaviors can...
Article
Full-text available
Disbonding in composite structures is a serious defect which can dramatically reduce the structures' life, and can lead to catastrophic failure. To avoid this, non-destructive testing or structural health monitoring techniques are needed. One such technique involves ultrasonic guided waves, which has recently found use in this field thanks to its a...