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Unidimensional modeling of 1–3 composite transducers
NDT Abstracts
46179 You, Z.; Lord, W. Elastic wave propagation in an infinite media Review of Progress in Quantitative Nondestructive
45606 Sansalone, M.; Lin, Y.; Carino, NJ. Impact-echo response of plates containing thin layers and voids Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9B, pp. 1935- 1942. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press ( 1990)
Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9A, pp. 133- 140. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990) This paper looks at finite element simulations of ultrasonic waves in an infinite medium. This approach is needed to cope with the complicated geometries commonly encountered in nondestructive evaluation applications. Viscous boundaries offer ease of implementation and cheap operation but can only achieve an approximation. Non-reflecting boundaries am only used for caseswhere a perfect absorber is necessaryto obtain the desired signals.
This paper highlights the results of a recent investigation into the feasibility of using the impact-echo technique to detect voids in plates containing thin layers of materials having different acoustic impedances. Finite element studieshave been metal or plastic thin layers and voids. The numerical studies provide an understanding of the propagation of stress waves in theselayered systemsand aide in the planning and interpretationof experimental work. A few key results from these analyseswill be presented. Subsequently, experimental results from a study of one type of civil structurecontaining thin layers (post-tensionedconcrete structures)will be discussed.
46123 Al-Nassar, Y.N.; Datta, S.K.; Shah, A.H. Scattering of Lamb waves by a normal rectangular strip weidment Ultrasonics, Vol. 29, No. 2, pp. 125-132 (Mar. 1991)
454 13 Sansalone, M.; Carino, NJ. Finite element studies of the impact-echo response of layered plates containing flaws International Advances in Nondestructive Testing. Edited by W.J. McGonnagle. Vol. 15, pp. 3 13-336. Gordon and Breach (1990)
A combined finite element and Lamb wave modal expansion method is presented here for analysing scattering of time harmonic Lamb waves by material and geometric irregularities in an isotropic linearly elastic infinite plate. All the irregularities are assumedto be containe.din a bounded region. the method is to replace this region with a finite element mesh. The method is illustrated by solving the problem of scattering of Lamb waves by a normal transversely anisotropic weldment. The reflection and transmission coefficients are computed for the first antisymmetric and symmetric incident modes. The validity and accuracy of the results are checked by satisfactionof the energy conservationprinciple.
The transientimpact responseof layered plates with and without flaws is determined using the finite element method. Specific casesthat are consider include acoustically soft layers on harder layers, hard layers on softer layers, voids at the interface between layers, and voids in a hard layer below a softer overlay. The details of these studies were. chosen so that the results could be used to determine the applicability of using the impact-echo method for determining layer thicknesses and detecting flaws in civil engineering structures.
45914 You, Z.; Lord, W. A finite element test bed for diffraction tomography Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9A, pp. 447- 454. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990) The data from finite element simulations of the forward problem can
45 180
Hayward, G.; Hossack, J.A.
Unidimensional modeling of 1-3 composite transducers Journal of the Acoustic Society of America, Vol. 88, No. 2, pp 599608, (Aug. 1990) This work uses an established modeling technique, supported by finite element analysis and experimental observation, to predict the mechanical, electrical, and piezoelectric properties of 1-3 composite sttuctures. These parameters are then combined in a modified thickness-drive model to predict the performance of composite. probe assemblies under realistic operating conditions. Accurate correlation between simulation and experimental results is demonstratedover an extensive range of ceramicpolymer volume fraction. Significantly, the results suggestthat composites that possessrelatively high-volume fractions of ceramic are superior to the lower volume fraction devices on which previous work has concentrated.
serve as raw data for input to inverse algorithms. Since it is easy to change the material parameters, shape of the scatterer, source signal and aperture sire, the finite element code provides an effective test bed on which the sensitivity of reconstruction techniques can be studied subject to a wide variety of test variables. Only isotropic materials are considered here. Through the Helmholtz decomposition,the elastic wave equation results in the Helmholtx equations. This paper, therefore, derives the diffraction tomographic algorithm form the scalar wave equation in 2-D geometries.
45141
Meeks, S.W.; Peter, D.; Horne, D.; Young, K.; Novotny,
V.
45900 Gun, N.Q.; Cawley, P. Three dimensional analysis of the vibration characteristics of piezoelectric discs Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9A, pp 789- 794. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990) In this paper the vibration characteristics of piezcelectric discs are
Residual stress mapping with a scanning phase measuring acoustic microscopy IEEE 1989 Ultrasonics Symposium Montreal, Quebec (Canada), 3-6 Oct. 1989 Vol. 2, pp. 809-812. Edited by B.R. McAvoy. IEEE (1989) A high resolution scanning phase-measuring acoustic microscope (SPAM) has been developed and used to image the near surface residual stress field around features etched in sputtered alumina via the acoustoelastic effect. This microscope operates at 670 MHz and has a resolution of 5-10 micron, depending upon the amount of defocus. Relative velocity changes of sample surface waves as small as 50 parts per million are resolved. Images of the stressfield at the tip of a 400 micron wide slot etched in alumina am presented and compared with a finite. element simulation.
analysed by a three dimensional finite element model, and the electrical impedance functions of FZTSA discs with Dn ratios of 20 and 10 are calculated. The calculations are checked by experimental measurements.
45856 Lin, Y.; Sansalone, M.; Carino, NJ. Finite element studies of the impact-echo response of plates containing thin layers and voids Journal of Nondestructive Evaluation, Vol. 9, No. 1, pp. 27-47 (Mar. 1990) In previous studies carried out by the authors, the finite element method has been shown to provide useful numerical solutionsfor a variety of cases
45 135 Lunceleur, P.; Fadili, S.; de Belleval, J.F.; Mercier, N. Visualization of transient behaviour of piezoelectric ceramics by mean of finite elements method IEEE 1989 Ultrasonics Symposium Montreal, Quebec (Canada), 3-6 Oct. 1989 Vol. 2, pp. 845-844. Edited by B.R. McAvoy. IEEE
involving bounded solids containing flaws. Currently the method is being used to establishthe basisfor a new nondestructiveevaluation techniquefor civil engineering structures.This technique is called impact-echo, and it is based on the use of low frequency, transient stress waves generated by elastic point impact. In this paper, the impact-echo response of plates containing thin layers is studiedusing finite element models. The purpose.of these studies was to determine the applicability of using the method for detecting voids in layered civil engineering structures. Results of the numerical studiesshow that it is feasible to use the impact-echo method for this application.
(1989) We present a method based on a finite element analysis which permits the calculation and the visualization of deformations of ultrasonic transducers in different configurations. The finite element procedures previously developed at UTC were originally developed in the monochromatic case and one of the difficulties of this work was the adaptation and the validation of the methods in the multifrequency excitation cases, mote realistic in the ama of NDE by ultrasonic methods. Several geometries were the tested and an experimental confirmation of the results is to be achieved.
252
46179 You, Z.; Lord, W. Elastic wave propagation in an infinite media Review of Progress in Quantitative Nondestructive
45606 Sansalone, M.; Lin, Y.; Carino, NJ. Impact-echo response of plates containing thin layers and voids Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9B, pp. 1935- 1942. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press ( 1990)
Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9A, pp. 133- 140. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990) This paper looks at finite element simulations of ultrasonic waves in an infinite medium. This approach is needed to cope with the complicated geometries commonly encountered in nondestructive evaluation applications. Viscous boundaries offer ease of implementation and cheap operation but can only achieve an approximation. Non-reflecting boundaries am only used for caseswhere a perfect absorber is necessaryto obtain the desired signals.
This paper highlights the results of a recent investigation into the feasibility of using the impact-echo technique to detect voids in plates containing thin layers of materials having different acoustic impedances. Finite element studieshave been metal or plastic thin layers and voids. The numerical studies provide an understanding of the propagation of stress waves in theselayered systemsand aide in the planning and interpretationof experimental work. A few key results from these analyseswill be presented. Subsequently, experimental results from a study of one type of civil structurecontaining thin layers (post-tensionedconcrete structures)will be discussed.
46123 Al-Nassar, Y.N.; Datta, S.K.; Shah, A.H. Scattering of Lamb waves by a normal rectangular strip weidment Ultrasonics, Vol. 29, No. 2, pp. 125-132 (Mar. 1991)
454 13 Sansalone, M.; Carino, NJ. Finite element studies of the impact-echo response of layered plates containing flaws International Advances in Nondestructive Testing. Edited by W.J. McGonnagle. Vol. 15, pp. 3 13-336. Gordon and Breach (1990)
A combined finite element and Lamb wave modal expansion method is presented here for analysing scattering of time harmonic Lamb waves by material and geometric irregularities in an isotropic linearly elastic infinite plate. All the irregularities are assumedto be containe.din a bounded region. the method is to replace this region with a finite element mesh. The method is illustrated by solving the problem of scattering of Lamb waves by a normal transversely anisotropic weldment. The reflection and transmission coefficients are computed for the first antisymmetric and symmetric incident modes. The validity and accuracy of the results are checked by satisfactionof the energy conservationprinciple.
The transientimpact responseof layered plates with and without flaws is determined using the finite element method. Specific casesthat are consider include acoustically soft layers on harder layers, hard layers on softer layers, voids at the interface between layers, and voids in a hard layer below a softer overlay. The details of these studies were. chosen so that the results could be used to determine the applicability of using the impact-echo method for determining layer thicknesses and detecting flaws in civil engineering structures.
45914 You, Z.; Lord, W. A finite element test bed for diffraction tomography Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9A, pp. 447- 454. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990) The data from finite element simulations of the forward problem can
45 180
Hayward, G.; Hossack, J.A.
Unidimensional modeling of 1-3 composite transducers Journal of the Acoustic Society of America, Vol. 88, No. 2, pp 599608, (Aug. 1990) This work uses an established modeling technique, supported by finite element analysis and experimental observation, to predict the mechanical, electrical, and piezoelectric properties of 1-3 composite sttuctures. These parameters are then combined in a modified thickness-drive model to predict the performance of composite. probe assemblies under realistic operating conditions. Accurate correlation between simulation and experimental results is demonstratedover an extensive range of ceramicpolymer volume fraction. Significantly, the results suggestthat composites that possessrelatively high-volume fractions of ceramic are superior to the lower volume fraction devices on which previous work has concentrated.
serve as raw data for input to inverse algorithms. Since it is easy to change the material parameters, shape of the scatterer, source signal and aperture sire, the finite element code provides an effective test bed on which the sensitivity of reconstruction techniques can be studied subject to a wide variety of test variables. Only isotropic materials are considered here. Through the Helmholtz decomposition,the elastic wave equation results in the Helmholtx equations. This paper, therefore, derives the diffraction tomographic algorithm form the scalar wave equation in 2-D geometries.
45141
Meeks, S.W.; Peter, D.; Horne, D.; Young, K.; Novotny,
V.
45900 Gun, N.Q.; Cawley, P. Three dimensional analysis of the vibration characteristics of piezoelectric discs Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9A, pp 789- 794. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990) In this paper the vibration characteristics of piezcelectric discs are
Residual stress mapping with a scanning phase measuring acoustic microscopy IEEE 1989 Ultrasonics Symposium Montreal, Quebec (Canada), 3-6 Oct. 1989 Vol. 2, pp. 809-812. Edited by B.R. McAvoy. IEEE (1989) A high resolution scanning phase-measuring acoustic microscope (SPAM) has been developed and used to image the near surface residual stress field around features etched in sputtered alumina via the acoustoelastic effect. This microscope operates at 670 MHz and has a resolution of 5-10 micron, depending upon the amount of defocus. Relative velocity changes of sample surface waves as small as 50 parts per million are resolved. Images of the stressfield at the tip of a 400 micron wide slot etched in alumina am presented and compared with a finite. element simulation.
analysed by a three dimensional finite element model, and the electrical impedance functions of FZTSA discs with Dn ratios of 20 and 10 are calculated. The calculations are checked by experimental measurements.
45856 Lin, Y.; Sansalone, M.; Carino, NJ. Finite element studies of the impact-echo response of plates containing thin layers and voids Journal of Nondestructive Evaluation, Vol. 9, No. 1, pp. 27-47 (Mar. 1990) In previous studies carried out by the authors, the finite element method has been shown to provide useful numerical solutionsfor a variety of cases
45 135 Lunceleur, P.; Fadili, S.; de Belleval, J.F.; Mercier, N. Visualization of transient behaviour of piezoelectric ceramics by mean of finite elements method IEEE 1989 Ultrasonics Symposium Montreal, Quebec (Canada), 3-6 Oct. 1989 Vol. 2, pp. 845-844. Edited by B.R. McAvoy. IEEE
involving bounded solids containing flaws. Currently the method is being used to establishthe basisfor a new nondestructiveevaluation techniquefor civil engineering structures.This technique is called impact-echo, and it is based on the use of low frequency, transient stress waves generated by elastic point impact. In this paper, the impact-echo response of plates containing thin layers is studiedusing finite element models. The purpose.of these studies was to determine the applicability of using the method for detecting voids in layered civil engineering structures. Results of the numerical studiesshow that it is feasible to use the impact-echo method for this application.
(1989) We present a method based on a finite element analysis which permits the calculation and the visualization of deformations of ultrasonic transducers in different configurations. The finite element procedures previously developed at UTC were originally developed in the monochromatic case and one of the difficulties of this work was the adaptation and the validation of the methods in the multifrequency excitation cases, mote realistic in the ama of NDE by ultrasonic methods. Several geometries were the tested and an experimental confirmation of the results is to be achieved.
252