TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Hochauflösende Röntgenrückstreutechnik zur zerstörungsfreien Untersuchung von Komponenten für die Luftfahrt T2 - DACH-Jahrestagung 2015 CY - Salzburg, Austria DA - 2015-05-11 PY - 2015 AN - OPUS4-33587 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - A new X-ray backscatter imaging technique for non-destructive testing of aerospace materials N2 - This paper presents a new X-ray backscatter technique (XBT) for non-destructive imaging of aerospace materials with only a single-sided access. It uses a special twisted slit collimator to inspect the whole object by changing the viewing direction of the X-ray backscatter camera. For the first time, the X-ray backscatter measurements were conducted using high-energy (>500 keV) X-ray sources. Experiments were performed on thick complex structured aluminium components, stringers and honeycomb structures to validate the applicability of the present technique to image small changes in the material properties and also to detect low-density material inclusions. In order to reduce the inspection time from hours to several seconds and to improve the image quality of the X-ray backscatter image, the backscattered signals were measured using a digital detector array with high spatial resolution (200 µm). The influence of the energy of the X-ray source and the slit width of the camera on the X-ray backscatter image were also investigated. In the proposed technique, the whole object is irradiated by an un-collimated X-ray beam resulting in a low image acquisition time of 3 min that facilitates the use of XBT for the real time NDT&E of aerospace materials. KW - X-ray backscatter imaging KW - Digital radiography KW - Digital detector array KW - Non-destructive evaluation KW - Aerospace applications PY - 2015 DO - https://doi.org/10.1016/j.ndteint.2014.09.008 SN - 0963-8695 VL - 70 SP - 41 EP - 52 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-32515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Hohendorf, Stefan A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Mobile high-energy X-ray radiography for nondestructive testing of cargo containers N2 - Radiologic evaluation techniques are nondestructive testing (NDT) used to detect the bulk of explosives and contraband materials in large objects. As compared to conventional low-energy (<450 key) X-ray imaging, high-energy (>1 MeV) digital X-ray radiography is required for the NOT of large containers because of the need for high penetration through thick materials, sensitivity, and the ability to distinguish between low-and high-Z materials. Mobile, high-energy, and high-resolution radiologic techniques are useful to detect contraband and threat materials in digital radiographic images of containers with complex packing. This paper presents a mobile, high-energy X-ray radiographic technique for the in-field nondestructive inspection of cargo containers. The developed experimental technique consisted of a betatron as a high-energy (7.5 MeV) X-ray source and a high-resolution (400 mu m) matrix detector for the digital X-ray imaging. In order to evaluate the detection efficiency and image quality of the measurement technique, a test specimen was proposed that was made of a 3 mm thick steel container with an inner dimension of 60 x 30 x 40 cm(3) comprising different low-and high-Z materials. Image quality indicators were used to assess the essential image quality parameters such as image basic spatial resolution, effective attenuation coefficient, and signal-to-noise ratio (SNR). Experimental investigations were performed on a 6.1 m sea freight container with mockup dangerous materials in complex packing. Preliminary experimental results showed that the proposed technique was able to distinguish between liquids and solids, as well as detect contraband materials. Furthermore, a remarkable SNR of 400 was achieved in the measured digital X-ray images. The influence of temperature on X-ray radiation dose rate at different X-ray energies was also investigated. Finally, important applications of the proposed technique in the context of maritime security are discussed. KW - Nondestructive testing KW - NDT KW - Digital radiography KW - High-energy X-ray imaging KW - Betatron KW - Digital detector arrays KW - Container inspection KW - Contraband detection KW - Image quality KW - SNR PY - 2015 SN - 0025-5327 VL - 73 IS - 2 SP - 175 EP - 185 PB - Society for Nondestructive Testing CY - Columbus, Ohio AN - OPUS4-32521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Venkata, K.C. A1 - Balasubramaniam, Krishnan T1 - Quantitative simulation of ultrasonic time of flight diffraction technique in 2D geometries using Huygens-Fresnel diffraction model: Theory and experimental comparison N2 - This article presents an analytical approach for simulation of ultrasonic diffracted wave signals from cracks in two-dimensional geometries based on a novel Huygens–Fresnel Diffraction Model (HFDM). The model employs the frequency domain far-field displacement expressions derived by Miller and Pursey in 2D for a line source located on the free surface boundary of a semi-infinite elastic medium. At each frequency in the bandwidth of a pulsed excitation, the complex diffracted field is obtained by summation of displacements due to the unblocked virtual sources located in the section containing a vertical crack. The time-domain diffracted wave signal amplitudes in a general isotropic solid are obtained by standard Fast Fourier Transform (FFT) procedures. The wedge based finite aperture transducer refracted beam profiles were modelled by treating the finite dimension transducer as an array of line sources. The proposed model is able to evaluate back-wall signal amplitude and lateral wave signal amplitude, quantitatively. The model predicted range-dependent diffracted amplitudes from the edge of a bottom surface-breaking crack in the isotropic steel specimen were compared with Geometrical Theory of Diffraction (GTD) results. The good agreement confirms the validity of the HFDM method. The simulated ultrasonic time-of-flight diffraction (TOFD) A-scan signals for surface-breaking crack lengths 2 mm and 4 mm in a 10 mm thick aluminium specimen were compared quantitatively with the experimental results. Finally, important applications of HFDM method to the ultrasonic quantitative non-destructive evaluation are discussed. KW - Ultrasonic non-destructive evaluation KW - Time-of-flight diffraction (TOFD) KW - Huygens–Fresnel diffraction KW - Cracks KW - Virtual sources PY - 2015 DO - https://doi.org/10.1016/j.ultras.2014.08.016 SN - 0041-624x VL - 55 SP - 33 EP - 41 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Dual High-Energy X-ray Digital Radiography for Material Discrimination in Cargo Containers T2 - 11th European Conference on Non-Destructive Testing CY - Prague, Czech Republic DA - 2014-10-06 PY - 2014 AN - OPUS4-32191 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Mobile high-energy X-ray inspection of cargo containers with complex scenarios: results of the SEFLOG project N2 - The research and development (R&D) in the field of safety and security of sea-freight Containers has gained more importance after the U.S. house resolution 1 (H.R.1). According to this law, all the freight Containers which are transported from non-U.S. port of origin to U.S. ports should be inspected 100% against explosive and contraband materials using non-intrusive imaging equipment and radiation detectors. As the port of Hamburg and Bremerhaven are the leading Container ports in Europe, it is essential to develop reliable and high-resolution detection technologies for the non-destructive inspection of large sea-freight Containers. T2 - Future Security 2014 - 9th Future security research conference CY - Berlin, Germany DA - 16.09.2014 KW - High-energy X-ray imaging KW - Digital detector arrays KW - Container inspection KW - Contraband detection KW - Image quality PY - 2014 SN - 978-3-8396-0778-7 SP - 591 EP - 594 AN - OPUS4-32238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Dual Energy Hochenergieradiographie für die Materialdiskriminierung in Cargo-Containern: Von der Forschung zur Anwendung T2 - DGZfP-Jahrestagung CY - Potsdam DA - 2014-05-26 PY - 2014 AN - OPUS4-32146 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Anwendung von Röntgenrückstreutechnik zur Untersuchung von Bauteilen für die Luftfahrtindustrie T2 - DGZfP-Jahrestagung CY - Potsdam DA - 2014-05-26 PY - 2014 AN - OPUS4-32148 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Christian A1 - Kolkoori, Sanjeevareddy A1 - Rahman, Mehbub-Ur A1 - Prager, Jens ED - Chimenti, D.E. ED - Bond, L.J. ED - Thompson, D.O. T1 - Imaging of transverse cracks in austenitic welds with RT-SAFT N2 - The synthetic aperture focusing technique (SAFT) is an imaging technique commonly used in ultrasonic inspection. In order to apply SAFT to the inspection of austenitic welds, the inhomogeneous anisotropic nature of the weld structure has to be taken into account. A suitable approach to accomplish this, is to couple the SAFT-algorithm with a ray tracing program (RT-SAFT). While SAFT-imaging of cracks in austenitic welds by use of ray tracing has been carried out before, all attempts so far were limited to longitudinal cracks which usually allows a treatment as 2-dimensional problem. In case of transverse cracks, a full 3-dimensional ray tracing is necessary in order to perform a SAFT-reconstruction. In this paper, we give an outline of our attempts to reconstruct images of transverse cracks in austenitic welds, utilizing 3-dimensional ray tracing and a layered structure model derived from an empirical model of grain orientations in welds. We present results of this RT-SAFT on experimental data taken from transverse cracks in different austenitic welds, which show that size and position of the cracks can be estimated with good accuracy, and compare them to images obtained by assuming an isotropic homogeneous medium which corresponds to the application of the classical SAFT-algorithm. T2 - 40th Annual review of progress in quantitative nondestructive evaluation CY - Baltimore, Maryland, USA DA - 21.07.2013 KW - SAFT KW - Austenitic welds KW - Transverse cracks KW - Ray tracing PY - 2014 SN - 978-0-7354-1212-5 SN - 978-0-7354-1211-8 DO - https://doi.org/10.1063/1.4864814 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1581 SP - 148 EP - 155 PB - AIP Publishing AN - OPUS4-30779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Wrobel, Norma A1 - Kolkoori, Sanjeevareddy T1 - EFNDT Working Group 5 - der Brückenschlag zwischen technischer und öffentlicher Sicherheit N2 - Die Arbeitsgruppe 5 der Europäischen Föderation für Zerstörungsfreie Prüfung (EFNDT Working Group 5 „Public Security and Safety“, EFNDT WG 5) verfolgt weiterhin das Ziel, organisatorisch weit auseinanderliegende Zuständigkeiten und Arbeitsgebiete zusammenzuführen, die weitgehend mit gleichen, zumindest ähnlichen Prinzipien und Methoden arbeiten. Auf der Suche nach neuen Wegen stoßen beide Seiten auf Gemeinsamkeiten. Dies gilt auch für neue Ansätze und Bewertungsmethoden von Techniken, mit denen Risiken vermindert werden sollen. Hierzu hat in Berlin ein Workshop im Oktober 2012 stattgefunden, auf dem parallele Projekte zur Container- und Frachtsicherheit zusammengeführt werden konnten. Herausgestellt wurde die Komplementarität der laufenden Projekte, gemeinsame Aspekte sollen künftig auch zusammen bearbeitet werden. Darüber hinaus wurden neue Methoden und Vorgehensweisen vorgestellt, aber auch die Sichtweise der Europäischen Kommission mit ihren Vorstellungen zu einem europäischen Markt für Sicherheitstechnik dargestellt. Angesprochen wurden bestehende und vorgeschlagene europaweite Regulierungen und das europäische Referenznetz zum Schutz kritischer Infrastrukturen (ERNCIP), welches ein Netzwerk von Laboratorien für den Test von Sicherheitstechnik zum Ziel hat. Auf technischem Sektor standen Methoden im Vordergrund, mit denen die Gesamtmenge eines Gefahrstoffes wie z.B. Sprengstoff erkannt werden können, und nicht nur Spuren als indirektem Hinweis. Die Arbeitsgruppe konnte somit erstmalig ein neutrales Forum für parallel laufende Projekte zur öffentlichen Sicherheit zur Verfügung stellen. Die auf den Workshops 2010 bis 2012 in Berlin gehaltenen Vorträge sind auf der EFNDT WG 5 – Webseite im geschützten Bereich zu finden. Nicht alles davon ist geeignet, es der allgemeinen Öffentlichkeit zugänglich zu machen. Deshalb sind alle Vorträge aus den Workshops in einem passwortgeschützten Verzeichnis abgelegt. Die Erteilung des Passwortes erfolgt über den Convenor der Arbeitsgruppe durch die EFNDT. Eine Erweiterung dieser Struktur zu einem Austauschforum ist vorgeschlagen. Zur Teilnahme daran sind nicht nur Mitglieder in den Gesellschaften für zerstörungsfreien Prüfung eingeladen, sondern auch diejenigen, die in den Anwendungsgebieten zur öffentlichen Sicherheit tätig sind. T2 - DGZfP-Jahrestagung 2013 CY - Dresden, Germany DA - 06.05.2013 PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-300309 SN - 978-3-940283-49-8 IS - DGZfP-BB 141 (Poster 36) SP - 1 EP - 8 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-30030 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Götschel, S. A1 - Höhne, Christian A1 - Kolkoori, Sanjeevareddy A1 - Mitzscherling, Steffen A1 - Prager, Jens A1 - Weiser, M. T1 - Ray tracing boundary value problems: simulation and SAFT reconstruction for ultrasonic testing N2 - The application of advanced imaging techniques for the ultrasonic inspection of inhomogeneous anisotropic materials like austenitic and dissimilar welds requires information about acoustic wave Propagation through the material, in particular travel times between two Points in the material. Forward ray tracing is a popular approach to determine traveling paths and arrival times but is ill suited for inverse problems since a large number of rays have to be computed in order to arrive at prescribed end points. In this contribution we discuss boundary value problems for acoustic rays, where the ray path between two given points is determined by solving the Eikonal equation. The implementation of such a two Point boundary value ray tracer for sound field simulations through an austenitic weld is described and its efficiency as well as the obtained results are compared to those of a forward ray tracer. The results are validated by comparison with experimental results and commercially available UT simulation tools. As an application, we discuss an implementation of the method for SAFT (Synthetic Aperture Focusing Technique) reconstruction. The ray tracer calculates the required travel time through the anisotropic columnar grain structure of the austenitic weld. There, the formulation of ray tracing as a boundary value Problem allows a straightforward derivation of the ray path from a given transducer Position to any pixel in the reconstruction area and reduces the computational cost considerably. T2 - 19th World Conference on Non-Destructive Testing 2016 CY - München, Germany DA - 13.06.2016 KW - Ultrasonic testing KW - SAFT KW - Ray tracing KW - Simulation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370494 UR - www.ndt.net/?id=19437 SP - ID 19437, 1 EP - 8 AN - OPUS4-37049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Hohendorf, Stefan A1 - Ewert, Uwe T1 - High energy X-ray imaging technology for the detection of dangerous materials in air freight containers N2 - In the context of the German aviation security research and development project SILUFRA (secure air freight transport chains), BAM has developed a high-resolution and high-energy X-ray imaging technology for the reliable detection of dangerous and illicit materials in densely packed air freight containers. In the developed technology, a novel combination of high-energy (2-7.5 MeV) X-ray betatron as the radiation source and a high-resolution digital detector array (DDA) for the X-ray imaging was utilized to improve the probability of detecting contraband and explosive materials by enhancing the spatial and contrast resolution in the digital X-ray image. In addition, flexible rotations of the high-energy X-ray source and the digital detector array can lead to clarify the suspicious region of interest (ROI) in air freight containers efficiently. Thus, reduces the false alarm rates and the need for expensive manual inspections of the whole container load. In order to evaluate the detection efficiency, we carried out the experimental investigations on a real air freight container loaded with typical cargo materials such as heavy automobile components and electronic products as well as mock-up dangerous and contraband materials. Furthermore, the material discrimination in the radiographic images was evaluated based on the dual high-energy X-ray imaging method. Finally, important applications of the proposed imaging technology to the air cargo security are discussed T2 - 2015 IEEE International Symposium on Technologies for Homeland Security (HST) CY - Waltham, MA, USA DA - 14.04.2015 KW - High-energy X-ray imaging KW - Betatron KW - Digital detector array (DDA) KW - Container inspection KW - Spatial resolution PY - 2015 SN - 978-1-4799-1736-5 DO - https://doi.org/10.1109/THS.2015.7225328 SP - 1 EP - 6 PB - IEEE AN - OPUS4-34025 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Ewert, Uwe T1 - A new X-ray backscatter technology for aviation security applications N2 - In order to enhance the supply chain security at airports, the German federal ministry of education and research has initiated the project ESECLOG (enhanced security in the air cargo chain) which has the goal to improve the threat detection accuracy using one-sided access methods. In this paper, we present a new X-ray backscatter technology for non-intrusive imaging of suspicious objects (mainly low-Z explosives) in luggage's and parcels with only a single-sided access. A key element in this technology is the X-ray backscatter camera embedded with a special twisted-slit collimator. The developed technology has efficiently resolved the problem related to the imaging of complex interior of the object by fixing source and object positions and changing only the scanning direction of the X-ray backscatter camera. Experiments were carried out on luggages and parcels packed with mock-up dangerous materials including liquid and solid explosive simulants. In addition, the quality of the X-ray backscatter image was enhanced by employing high-resolution digital detector arrays. Experimental results are discussed and the efficiency of the present technique to detect suspicious objects in luggages and parcels is demonstrated. At the end, important applications of the proposed backscatter imaging technology to the aviation security are presented. T2 - 2015 IEEE International Symposium on Technologies for Homeland Security (HST) CY - Waltham, MA, USA DA - 14.04.2015 KW - X-ray backscatter imaging KW - Digital radiography KW - Detection of dangerous materials KW - Luggage inspection KW - One-sided access method KW - Security applications PY - 2015 SN - 978-1-4799-1736-5 DO - https://doi.org/10.1109/THS.2015.7225329 SP - 1 EP - 5 PB - IEEE AN - OPUS4-34027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - High energy X-ray imgaging technology for the detection of dangerous materials in air freight containers T2 - IEEE International Symposium on Technologies for Homeland Security (HST) 2015 CY - Waltham, MA, USA DA - 2015-04-14 PY - 2015 AN - OPUS4-34039 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Acoustic Wave Energy Skewing and Coefficients for the reflected and transmitted Plane Waves in General Homogenous Transversely-Isotropic Austentic Materials T2 - 8th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components CY - Berlin, Germany DA - 2010-09-29 PY - 2010 AN - OPUS4-22236 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Simulation of Ultrasonic Sound Fields in Anisotropic Materials Using 2-D Ray Tracing Method T2 - International Congress on Ultrasonics (ICU), University of Gdansk CY - Gdansk, Poland DA - 2011-09-05 PY - 2011 AN - OPUS4-24453 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Quantitative Evaluation of Ultrasonic Sound Field in Anisotropic Austenitic welds using 2D Ray tracing model T2 - 38th Annual Reviwe if Progress in Quantitative Non- Destructive Evaluation (QNDE 2011), University of Vermont CY - Burlington, VT, USA DA - 2011-07-17 PY - 2011 AN - OPUS4-24333 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rahman, Mehbub-Ur A1 - Kolkoori, Sanjeevareddy A1 - Prager, Jens T1 - Elastische Wellenausbreitung in austenitischen Schweißnähten - numerische Simulationen und deren messtechnische Validierung N2 - In diesem Beitrag wird die numerische Modellierung und deren messtechnische Validierung der elastischen Wellenausbreitung in austenitischen Schweißnähten vorgestellt. Die Ultraschallprüfung von austenitischen Schweißverbindungen war und ist immer noch eine der schwierigsten Aufgaben der ZfP. Für eine optimierte Prüfkonfiguration ist es notwendig, verschiedene Prüfparameter wie Einschallwinkel, Prüfkopfposition und -Orientierung richtig einzustellen. Um die beste Anordnung zu ermitteln, wurde die Schallausbreitung in den austenitischen Schweißnähten mit verschiedenen Verfahren wie elastische finite Integrationstechnik (EFIT) und Raytracing simuliert. Mit Hilfe der Simulationsergebnisse wurde die verwendete Gruppenstrahlerprüftechnik optimiert. Es wurden zahlreiche Untersuchungen an anisotropen Testkörpern in V-Durchschallung und an bezüglich der Schweißnaht transversal orientierten Rissen durchgefühlt. Die Ergebnisse der auf Raytracing bzw. EFIT basierenden Simulationstools wurden untereinander und auch mit den Messergebnissen verglichen. T2 - DAGA 2011 - 37. Jahrestagung für Akustik - Fortschritte der Akustik CY - Düsseldorf, Deutschland DA - 21.03.2011 PY - 2011 SN - 978-3-939296-02-7 SP - 1 EP - 2 AN - OPUS4-25224 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Rahman, Mehbub-Ur A1 - Prager, Jens A1 - Kreutzbruck, Marc T1 - Acoustic wave energy skewing and coefficients for the reflected and transmitted plane waves in general homogeneous transversely-isotropic austenitic materials N2 - In this contribution a simulation tool is developed to compute the energy skewing angles and energy coefficients for the reflected and refracted plane waves in following general cases: (1) reflection and refraction of plane elastic waves at an interface between isotropic and transversely isotropic solid, (2) reflection and refraction of plane elastic waves at an interface between transversely isotropic and isotropic solid, (3) reflection and refraction of plane elastic waves at an interface between two general transversely isotropic solid and (4) reflection of plane elastic waves from a stress free boundary of a transversely isotropic solid. Computational results for analytically evaluated acoustic wave energy skewing angles and energy reflection and transmission coefficients in acoustically anisotropic materials such as austenitic steel materials exhibiting columnar grain orientation are presented. The obtained results show that the acoustic energy skewing angles and coefficients in austenitic steel materials strongly depend upon the columnar grain orientation and are less influenced by the grain orientations which are parallel and perpendicular to the interface. T2 - 8th International conference on NDE in relation to structural integrity for nuclear and pressurised components CY - Berlin, Germany DA - 2010-09-29 KW - Anisotropy KW - Austenitic weld material KW - Energy skewing KW - Critical angle KW - Energy flux vector KW - Energy coefficients PY - 2010 SN - 978-3-940283-30-6 IS - DGZfP-BB 125 (Th.1.C.3) SP - 1 EP - 10 CY - Berlin AN - OPUS4-25232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Rahman, Mehbub-Ur A1 - Chinta, P.K. A1 - Prager, Jens T1 - Computationally efficient ray tracing algorithm for simulation of transducer fields in anisotropic materials N2 - This contribution describes a computationally efficient ray tracing algorithm for evaluating transducer generated ultrasonic wave fields in anisotropic materials such as austenitic cladded and austenitic weld components. According to this algorithm, ray paths are traced during its propagation through various layers of the material and at each Interface the problem of reflection and transmission is solved. The presented algorithm evaluates the transducer generated ultrasonic fields accurately by taking in to account the directivity, divergence, density of rays, phase relations as well as transmission coefficients. The ray tracing algorithm is able to calculate the ultrasonic wave fields generated by a point source as well as a finite dimension transducer. The simulation results are compared quantitatively with the results obtained from Elastodynamic Finite Integration Technique (EFIT) on several configurations generally occuring in the ultrasonic non destructive testing of anisotropic materials. The excellent agreement between both models confirms the validity of the presented ray tracing algorithm. Finally, the ray tracing model results are also validated by means of experiments. T2 - NDE 2011 - National seminar & exhibition on non-destructive evaluation CY - Chennai, India DA - 08.12.2011 KW - Ultrasonic sound field KW - Ray tracing KW - Directivity KW - Anisotropy KW - Austenitic weld PY - 2011 SP - 482 EP - 486 AN - OPUS4-25329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - Computationally Efficient Ray Tracing Algorithm for Simulation of Transducer Fields in Anisotopic Materials T2 - 21st Annual ISNT Conference on Non Destructive Evaluation (NDE 2011) CY - Chennai, India DA - 2011-12-08 PY - 2011 AN - OPUS4-25300 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy T1 - A Comparative Study of Ray Tracing and CIVA for Ultrasonic Inspection of Anisotropic Inhomogeneous Austenitic Welds T2 - Review of Progress in Quantitative non-destructive Evaluation (QNDE 2012) CY - Denver, CO, USA DA - 2012-07-15 PY - 2012 AN - OPUS4-26714 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Shokouhi, Parisa A1 - Höhne, Christian A1 - Rahman, Mehbub-Ur A1 - Kreutzbruck, Marc A1 - Prager, Jens T1 - A comparative study of ray tracing and CIVA simulation for ultrasonic examination of anisotropic inhomogeneous austenitic welds N2 - Ultrasonic examination of anisotropic inhomogeneous austenitic welds is challenging, because of the columnar grain structure of the weld leads to beam skewing and splitting. Modeling tools play an important role in understanding the ultrasound field propagation and optimization of experimental parameters during the ultrasonic testing of austenitic welds as well as the interpretation of the test results. In this contribution, an efficient theoretical model based on the ray tracing concepts is developed to calculate the ultrasonic fields in inhomogeneous austenitic welds quantitatively. The developed model determines the ultrasound fields by taking into account the directivity of the ray source, the inhomogenity of the weld as well as ray transmission coefficients. Directivity of the ray source in columnar grained austenitic materials (including layback orientation) is obtained in three dimensions based on Lamb's reciprocity theorem. Ray energy reflection and transmission coefficients at an interface between two general columnar grained austenitic materials are calculated in three dimensions. The ray tracing model predictions on inhomogeneous austenitic weld material are compared against those from CIVA, a commercial non-destructive modeling and simulation tool. The ultrasonic modeling tools in CIVA are based on semi-analytical solutions. For beam propagation simulation, a so-called 'pencil method' is used, which involves modeling the probe as a set of individual source points, each radiating 'a bundle' of diverging rays into the medium and integrating those elementary contributions. Inhomogenity in the weld region is approximated by mapping the grain orientations on weld macrograph. Simulation results for ultrasonic field profiles for an austenitic weld are shown to be in good agreement with the corresponding experimental results. T2 - 39th Annual review of progress in quantitative nondestructive evaluation CY - Denver, Colorado, USA DA - 15.07.2012 KW - Crystal microstructure KW - Ray tracing KW - Ultrasonic materials testing KW - Ultrasonic propagation KW - Ultrasonic reflection KW - Ultrasonic transmission KW - Welds PY - 2013 SN - 978-0-7354-1129-6 DO - https://doi.org/10.1063/1.4789158 SN - 0094-243X SN - 1551-7616 N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1511 SP - 1043 EP - 1050 PB - AIP Publishing AN - OPUS4-27736 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -