Topological imaging of tubular structures using ultrasonic guided waves
Description
Tubular structures are widely used in a variety of industries such as Aerospace, Oil and Gas, Nuclear, etc. Non Destructive Evaluation (NDE) of these structures plays a crucial role during it's life cycle. In order to test large structures with limited accessibility, guided wave testing was developed as a viable solution. Due to the nature of these waves, they are able to propagate over large distances without losing much of their energy. However, they are also complex in that their velocity is frequency dependent i.e. they are dispersive. Conventionally, guided wave testing require costly finite element simulations. This thesis offers an alternative to such simulations with a quick and robust method to simulate guided wave propagation in tubular structures. Based on these calculations, the aim of this work is to obtain the 3D topological image of multilayered isotropic tubular structures using ultrasonic guided waves to locate defects. A mathematical model has been proposed where the wave equation is converted to an ordinary differential equation with respect to radius 'r' using the Fourier and Laplace transforms for the spatial and temporal variables respectively. The partial wave solution, expressed as a combination of Bessel's functions, allows for the creation of a fast robust semi-analytical algorithm to compute the Green function in tubular structures. A model to approximate numerical defects is then developed. The defect response is considered as the cumulative response of secondary sources, aiming to negate the incident and diffracted stress field present within it. Next, the numerical model is validated with experimental measurements. Finally, the technique of Topological Imaging is introduced. This method of imaging is based on the idea of performing a correlation between two wave fields for defect localization. The versatility and flexibility of the numerical tool in conjunction with the method of imaging is then successfully demonstrated by localising and imaging a multitude of numerical and experimental defects with dimensions as low as 1/40 of the wavelength. (author)
Abstract (French)
Les structures tubulaires sont largement utilisees dans diverses industries telles que l'aerospatiale, le petrole et le gaz, le nucleaire, etc. Le Controle Non Destructive (CND) de ces structures joue un role crucial au cours de leur cycle de vie. Afin de tester de grandes structures avec une accessibilite limitee, la methode de CND utilisant des ondes guidees a ete developpee comme une solution viable. En raison de la nature de ces ondes, elles sont capables de se propager sur de grandes distances sans perdre une grande partie de leur energie. Cependant, elles sont complexes puisque leur vitesse depend de la frequence, c'est-a-dire qu'elles sont dispersives. Classiquement, l'etude de ce type d'ondes necessite des simulations par elements finis couteuses. Cette these propose une alternative a de telles simulations avec une methode rapide et robuste pour simuler la propagation d'ondes guidees dans des structures tubulaires. Partant de ces calculs, pour localiser des defauts, l'objectif de ce travail est d'obtenir des images topologiques 3D de structures tubulaires isotropes multicouches par propagation de ces ondes guidees ultrasonores. Un modele mathematique est propose ou l'equation d'onde est convertie en une equation differentielle ordinaire par rapport au rayon 'r' en utilisant les transformees de Fourier et de Laplace pour les variables spatiales et temporelles respectivement. La solution en ondes partielles, exprimee comme une combinaison des fonctions de Bessel, permet la creation d'un algorithme semi-analytique rapide et robuste pour calculer la fonction de Green de structures tubulaires. Un modele approche en presence de defauts numeriques est ensuite developpe. La reponse des defauts est consideree comme la reponse cumulative des sources secondaires, visant a annuler le champ de contraintes incident et diffracte present en son sein. Ensuite, le modele numerique est valide par des mesures experimentales. Enfin, la technique de l'imagerie topologique est introduite. Cette methode d'imagerie est basee sur la correlation entre les champs ultrasonores sans et avec defaut. La polyvalence et la flexibilite de l'outil numerique en conjonction avec cette methode d'imagerie sont ensuite demontrees avec succes en localisant et imageant une multitude de defauts numeriques et experimentaux avec des dimensions aussi faibles que 1/40e de la longueur d'onde
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Additional details
Additional titles
- Original title (English)
- Imagerie topologique de structures tubulaires par ondes ultrasonores guidees
Publishing Information
- Imprint Pagination
- 143 p.
- Report number
- FRCEA-TH--13241
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 53064474
- Subject category
- S42: ENGINEERING;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- ALGORITHMS; BESSEL FUNCTIONS; GREEN FUNCTION; MATHEMATICAL MODELS; NONDESTRUCTIVE TESTING; ULTRASONIC WAVES; WAVEGUIDES
- Descriptors DEC
- FUNCTIONS; MATERIALS TESTING; MATHEMATICAL LOGIC; SOUND WAVES; TESTING
Optional Information
- Notes
- 120 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses