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 -