TY - CONF A1 - Rahman, Mehbub-Ur A1 - Prager, Jens T1 - Simulation of lamb wave propagation with elastodynamic finite integration technique (EFIT) T2 - DAGA 2012 - 38. Jahrestagung für Akustik - Fortschritte der Akustik N2 - This paper presents the numerical modeling of the Lamb wave propagation in plate like structures with the Elastodynamic Finite Integration Technique (EFIT) and its validation with the measured results. In general, Lamb waves offer an attractive method to detect the defects inside long plate like structures efficiently. However, such a nondestructive testing (NDT) requires profound understanding of the Lamb wave propagation in the plates, generation of the symmetric and anti-symmetric modes of different orders and their interaction with the defects of the materials. Modern simulation tools based on numerical methods can be used to model this complex NDT situation. EFIT is an effective tool to model such problems in an efficient way. With the help of the simulation results obtained from the EFIT tool the propagation of different symmetric and antisymmetric Lamb wave modes is analyzed and thus a proper technique is developed to excite different modes and to separate them from each other precisely. A validation of the numerical results with the measured results is also presented. T2 - DAGA 2012 - 38. Jahrestagung für Akustik - Fortschritte der Akustik CY - Darmstadt, Deutschland DA - 2012-03-19 PY - 2012 SP - 953 EP - 954 PB - Deutsche Gesellschaft für Akustik e.V. AN - OPUS4-25999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rahman, Mehbub-Ur A1 - Prager, Jens ED - Linde, B. B. J. ED - Paczkowski, J. ED - Ponikwicki, N. T1 - Modeling of lamb wave propagation with elastodynamic finite integration technique T2 - International congress on ultrasonics N2 - This paper presents the numerical modeling of the Lamb wave propagation in thin plates with the elastodynamic finite integration technique (EFIT) and its validation with the measured results. In general, Lamb waves offer an attractive method to detect the defects inside long plate like structures efficiently. However, such a nondestructive testing (NDT) requires profound understanding of the Lamb wave propagation in the plates, generation of the symmetric and anti-symmetric modes of different orders and their interaction with the defects of the materials. Modern simulation tools based on numerical methods such as the finite integration technique (FIT), the finite element method (FEM) and the boundary element method (BEM) can be used to model this NDT situation. The elastodynamic finite integration technique (EFIT) is an effective tool to model Lamb wave propagation in plates over long distances in an efficient way. With the help of the simulation results obtained from the EFIT tool the propagation of different symmetric and anti-symmetric modes is analyzed and thus a proper technique is developed to excite different modes and to separate them from each other precisely. A validation of the numerical results with the analytical results is also presented. T2 - International congress on ultrasonics CY - Gdansk, Poland DA - 2011-09-05 KW - NDT KW - EFIT KW - Lamb wave KW - Symmetric and anti-symmetric modes PY - 2012 SN - 978-0-7354-1019-0 DO - https://doi.org/10.1063/1.3703226 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1433 SP - 455 EP - 458 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Rahman, Mehbub-Ur A1 - Prager, Jens T1 - 3D ray tracing model for ultrasound field evaluation in inhomogeneous anisotropic materials: model and experimental validation T2 - DAGA 2012 - 38. Jahrestagung für Akustik - Fortschritte der Akustik N2 - In this contribution a 3D ray tracing model for ultrasonic field evaluation in inhomogeneous anisotropic materials such as austenitic welds is presented. The inhomogenity of austenitic weld material is represented as several homogeneous layers. The general problem of energy reflection and transmission at the boundaries of the layers are solved resulting 3D amplitude and energy reflection and transmission coefficients. The directivity factor for the ray in general arbitrary oriented austenitic weld material (including lay back orientation) is determined based on Lamb’s reciprocity theorem. The transducer excited ultrasonic fields are accurately evaluated by employing ray directivity factor, transmission coefficients, divergence of the ray bundle and density of rays. Finally, the comparison between theoretical and experimental results will be described. T2 - DAGA 2012 - 38. Jahrestagung für Akustik - Fortschritte der Akustik CY - Darmstadt, Deutschland DA - 2012-03-19 KW - Ultrasonic field KW - 3D ray tracing KW - Inhomogeneous KW - Austenitic weld PY - 2012 SP - 959 EP - 960 PB - Deutsche Gesellschaft für Akustik e.V. AN - OPUS4-26204 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 - Kreutzbruck, Marc A1 - Prager, Jens ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Quantitative evaluation of ultrasonic sound fields in anisotropic austenitic welds using 2D ray tracing model T2 - Review of progress in quantitative nondestructive evaluation, volume 31 N2 - Ultrasonic investigation of inhomogeneous anisotropic materials such as austenitic welds is complicated because its columnar grain structure leads to curved energy paths, beam splitting and asymmetrical beam profiles. A ray tracing model has potential advantage in analyzing the ultrasonic sound field propagation and there with optimizing the inspection parameters. In this contribution we present a 2D ray tracing model to predict energy ray paths, ray amplitudes and travel times for the three wave modes quasi longitudinal, quasi shear vertical, and shear horizontal waves in austenitic weld materials. Inhomogenity in the austenitic weld material is represented by discretizing the inhomogeneous region into several homogeneous layers. At each interface between the layers the reflection and transmission problem is computed and yields energy direction, amplitude and energy coefficients. The ray amplitudes are computed accurately by taking into account directivity, divergence and density of rays, phase relations as well as transmission coefficients. Ultrasonic sound fields obtained from the ray tracing model are compared quantitatively with the 2D Elastodynamic Finite Integration Technique (EFIT). The excellent agreement between both models confirms the validity of the presented ray tracing results. Experiments are conducted on austenitic weld samples with longitudinal beam transducer as transmitting probe and amplitudes at the rear surface are scanned by means of electrodynamical probes. Finally, the ray tracing model results are also validated through the experiments. T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 2011-07-17 KW - Ultrasonic sound field KW - Ray tracing KW - Ray directivity KW - Austenitic weld PY - 2012 SN - 978-0-7354-1013-8 DO - https://doi.org/10.1063/1.4716359 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1430 SP - 1227 EP - 1234 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26205 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 - Boehm, Rainer A1 - Prager, Jens ED - Linde, B. B. J. ED - Paczkowski, J. ED - Ponikwicki, N. T1 - Simulation of ultrasonic fields in anisotropic materials using 2D ray tracing method T2 - International congress on ultrasonics N2 - Ultrasound propagation in inhomogeneous anisotropic materials is difficult to examine because of the directional dependency of elastic properties. Simulation tools play an important role in developing advanced reliable ultrasonic testing techniques for the inspection of anisotropic materials particularly austenitic cladded materials and dissimilar welds. A 2-D Ray tracing method is developed for evaluating ray path, amplitude and travel time for three wave modes namely quasi longitudinal wave (qP), quasi shear vertical wave (qSV) and shear horizontal waves (SH) in anisotropic materials such as austenitic cladded materials. The inhomogenity in the anisotropic material is represented by discretizing the anisotropic region into several homogeneous layers. The ray paths are traced during its propagation through the various interfaces between those layers. At each interface the problem of reflection and refraction is solved. The ray amplitudes are computed by taking into account the directivity and phase relations. Ray divergence variation and ray transmission coefficients at each refraction boundary are considered. The Ray tracing results for ultrasonic field profiles in austenitic cladded materials are validated quantitatively by 2-D Elastodynamic Finite Integration Technique (EFIT) results and by the experiments. T2 - International congress on ultrasonics CY - Gdansk, Poland DA - 2011-09-05 KW - Ray path KW - Energy vector KW - Austenitic cladded material KW - Ultrasonic beam profile PY - 2012 SN - 978-0-7354-1019-0 DO - https://doi.org/10.1063/1.3703288 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1433 SP - 743 EP - 746 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26207 LA - eng 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 T2 - DAGA 2011 - 37. Jahrestagung für Akustik - Fortschritte der Akustik 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 T2 - 8th International conference on NDE in relation to structural integrity for nuclear and pressurised components (DGZfP-Proceedings) 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 T2 - NDE 2011 - National seminar & exhibition on non-destructive evaluation (Proceedings) 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 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 T2 - 39th Annual review of progress in quantitative nondestructive evaluation (Proceedings) 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 - 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 T2 - 40th Annual review of progress in quantitative nondestructive evaluation (Proceedings) 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 -