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The use of an optical interference method to measure erosion rates of automotive clearcoats
N DT Abstracts 61788 Shi, B J(.; Gong, J Nondestructive image detection of surface a n d subsurface defects of solid m a t e r i a l s ]by (optical b e a m deflection) OBD Optics and Lasers in Engiaeering, Vol. 25, No. 2-3, pp. 121-131 (1996) The ~ u r e m e n t principle for detecting surface and sub-surface defects in solid materials by the optical beam deflection method (OBD) is described. The detectable depth of sub-surface defects is predicted through calculating the dependence of the surface temperature distribution of a solid sample, typically metal AI, on the thickness of the solid material and modulation frequencies of a pump laser. The defects in surface and sub-surface of some samples such as carbon film coated on glass, C/C composite material and mete~llic AI, etc., experimentally detected and directly displayed by grey imalge or 3D image.
61338 Steinchen, W.; Yang, L.X.; Schuth, M. T V - s h e a r o g r a p h y for m e a s u r i n g 3D-strains Strain, Vol. 32, No. 2, (May 1996) Using shearography two states of deformation are recorded by doubly exposing a Holotest film in an ordinary camera or stored by an electronic image processing system. In the lens of the camera a sheafing dement inside or outside the focus is integrated or the lateral Michelson shearing interferometer is used. Local deformation irregularities caused by a defect under or on the surface of the specimen create strain concentrations; the homogeneous surrounding is poorly superimposed by an interference pattern. The shearogram shows dark and bright fringes which are the functions of the displacement derivative. The holographic interferometry measures the out of plane deformation directly. Terms of the out of plane strain can he determined by the sbearographic method as well as the in plane strain fringes which are described.
Crosby, P,4.; Powell, G.R.; Feranando, G.F.; France, C.M.; Waters, D.N.; Spoon,,'er, R.C.
61335
C u r e m o n i t o r i n g of epoxy resins using optical fibres sensors Sensors and their Applications VII. Proceedings of the 7th Conference on Sensors ~td their Applications, Dublin, Ireland, 10-13 Sep. 1995. pp. 255-259. Edited by A.T. Augousti, Institute of Physics (1995). ISBN 07503033 ! X Two methods utilizing optical fibre sensors to follow refractive index changes and chemical change~ during epoxy resin cure are described. A laser diode source, whose w~welength was remote from any interfering absorption bands of the resin was used to observe changes in the light guiding characteristics through a stripped optical fibre embedded in a curing resin. Results were compared to data obtained from transmission FTIR spectroscopy measurements on the same sample. Good correlation was obtained between the two techniques. The use of an optical fibre evanescent wave sensor to follow chang¢~ in near-infrared absorption bands during epoxy cure was demonstrated. The depletion of a N-H absorption band at 1542nm was followed for the room temperature cure of a resin cured with an amine hardener. Spectra showed effects due to the increase in material refractive index as well as absorption band depletion.
M e a s u r e m e n t of process-induced strains in composite materials using e m b e d d e d fiber optic sensors SPIE Smart Structures and Materials Conference, San Diego, CA (United States), 26-29 Feb. 1996, 9 pp. DE96008710. U.S. Government Printing Office (1996) This paper presents the result of experiments to measure the internal strains and temperatures that are generated in graphite-epoxy composite specimens during processing using embedded fiber optic strain sensors and thermocouples. Extrinsic Fabry-Perot interferometer, Bragg grating strain sensors, and thermocouples were embedded in graphite/epoxy composite laminates prior to cure.
61780
Lawrence, C.M.; Nelson, D.V.; Spingarn, J.R.; Bennett,
T.E.
61173 Zhong, Y. Image segmentation for defect detection o n veneer surfaces Dissertation Abstracts International, Vol. 56, No. 6, 198 pp. (1995) (DA9535991) Nine algorithms covering three segmentation technique categories were explored. The performances of these nine algorithms were tested and compared under the combinations of two camera resolutions (5-but and 8bit), three color spaces (RGB, Lab, and gray-scale), and seven surface features (clear wood, blue stain, loose knot, pitch pocket, pitch streak, tight knot, and wane). Ten sample images for each of seven surface features on Douglas-fir veneer [Pseudotsuga menziesii] were used. Ten measures were proposed for performance evaluation. A multi- factor factorial ANOVA was used in the performance tests and comparisons.
61589 Lanza, F.; Geiger, F.; Wagner, V.; Visentini, L. Use of laser pulses to evaluate the resistance to t h e r m a l cycles of Z r O ( 2 ) t h e r m a l b a r r i e r o n gas t u r b i n e h a r d w a r e Commission of the Eun)pean Communities, EUR-15406-EN (1993) A thermal barrier formed by a layer of sprayed zirconia stabilised with yttria is largely used in the gas turbine components. The selection and qualification of the types of coatings has been made in the past using global tests. Simplified tests are commonly used just to obtain a comparative ranking between the different coatings. A test using laser shots having a duration time often milliseconds and a power of 2 kW/cm2 has been used to compare three different coatings. Single shots and series of 100 shots have been applied. The metallographic analysis of the different types of coatings after the tests allows information on their resistance to thermal fatigue to be obtained.
60748 Pepper, D.M. Nondestructive testing using n o n l i n e a r optically based s m a r t pixel processors Proceedings of an IEEE Conference on Nonlinear Optics. Material Fundamentals and Applications, Waikoloa (Hawaii), 25-29 Jul. 1994. pp. 265-268. IEEE (1994). ISBN 0780314735. There is an on-going need in the commercial sector to rapidly and nondestructively inspect components, ex situ and in situ, under harsh in-factory and field-testing conditions. To motivate this need, we cite below three such examples in rather diverse industrial applications. This will he followed by how optics and, more specifically, how so-called "smart-pixel processors," can augment existing inspection systems - all with the goal of enhancing the performance of the diagnostic. By smart-pixel processors, we imply that multi-pixelated information can be processed in parallel, with differential phase information preserved amongst the pixels. Typically, such processors can he realized via architectures involving phase-conjugate mirrors, either isolated, or in conjunction with spatial light modulators.
61582 Eisgruber, I.L.; Sites, J.R.; Matson, R.I.; Emergy, K.A. I n t e r p r e t a t i o n of laser scans from thin-film polycrystalline photovoltaic modules Proceedings of the Institute of Electrical and Electronics Engineers 1st World Conference on Photovoltaic Energy Conversion, Waikoloa, H! (United States), Vol. 1, 5-9 Dec. 1994. pp. 283-286. ISBN 078031459X Issues are addressed for thin film CdTe and CuinSesub(2) (CIS) modules and cells using a recently developed computer-controlled largescale laser scanner at the National Renewable Energy Laboratory (NREL). This instrument was designed to serve as a tool for research, device and module quality control, and module failure analysis. The thrust of the report is twofold: (i) the development of reliable submillimeter module characterization techniques and analysis and (2) presentation of the results of such techniques as applied to thin film CdTe and CIS modules.
60745 Frost, B.G.; van Hulst, N.F.; Lunedei, E.; Matteucci, G.; Rikkers, E. Study of the leakage field of magnetic force microscopy thin-film tips using electron holography Applied Physics Letters, Vol. 68, No. 13, pp. 1865-. (25 Mar. 1996) Electron holography is applied for the study of the leakage field of thin-film ferromagnetic tips used as probes in magnetic force microscopy. We used commercially available pyramidal tips covered on one face with a thin NiCo film, which were then placed in a high external magnetic field directed along the pyramid axis. Good agreement between simulated and experimental electron phase difference maps allows to measure the local flux from the ferromagnetic tips and therefore to evaluate the perturbation induced by the microprobe stray field on the sample area.
61366 Holt, M.S.; lyengar, R. T h e use of a n optical interference method to measure erosion rates of automotive d e a r c t m t s Society of Automotive Engineers, Paper No. 950798 (Jan. 1996) One important aspect of clearcoat degradation which affects interpretation of the results of ;~1 these methods is erosion. This paper will describe an accurate method for determining erosion rates by an optical interference method. This method will be used to demonstrate the effect of light stabilizers on erosion rate:~.
60531 Bradley, J. New technique for bore quality inspection Quality Testing Today, pp. 536-537 (Sep. 1995)
131
61338 Steinchen, W.; Yang, L.X.; Schuth, M. T V - s h e a r o g r a p h y for m e a s u r i n g 3D-strains Strain, Vol. 32, No. 2, (May 1996) Using shearography two states of deformation are recorded by doubly exposing a Holotest film in an ordinary camera or stored by an electronic image processing system. In the lens of the camera a sheafing dement inside or outside the focus is integrated or the lateral Michelson shearing interferometer is used. Local deformation irregularities caused by a defect under or on the surface of the specimen create strain concentrations; the homogeneous surrounding is poorly superimposed by an interference pattern. The shearogram shows dark and bright fringes which are the functions of the displacement derivative. The holographic interferometry measures the out of plane deformation directly. Terms of the out of plane strain can he determined by the sbearographic method as well as the in plane strain fringes which are described.
Crosby, P,4.; Powell, G.R.; Feranando, G.F.; France, C.M.; Waters, D.N.; Spoon,,'er, R.C.
61335
C u r e m o n i t o r i n g of epoxy resins using optical fibres sensors Sensors and their Applications VII. Proceedings of the 7th Conference on Sensors ~td their Applications, Dublin, Ireland, 10-13 Sep. 1995. pp. 255-259. Edited by A.T. Augousti, Institute of Physics (1995). ISBN 07503033 ! X Two methods utilizing optical fibre sensors to follow refractive index changes and chemical change~ during epoxy resin cure are described. A laser diode source, whose w~welength was remote from any interfering absorption bands of the resin was used to observe changes in the light guiding characteristics through a stripped optical fibre embedded in a curing resin. Results were compared to data obtained from transmission FTIR spectroscopy measurements on the same sample. Good correlation was obtained between the two techniques. The use of an optical fibre evanescent wave sensor to follow chang¢~ in near-infrared absorption bands during epoxy cure was demonstrated. The depletion of a N-H absorption band at 1542nm was followed for the room temperature cure of a resin cured with an amine hardener. Spectra showed effects due to the increase in material refractive index as well as absorption band depletion.
M e a s u r e m e n t of process-induced strains in composite materials using e m b e d d e d fiber optic sensors SPIE Smart Structures and Materials Conference, San Diego, CA (United States), 26-29 Feb. 1996, 9 pp. DE96008710. U.S. Government Printing Office (1996) This paper presents the result of experiments to measure the internal strains and temperatures that are generated in graphite-epoxy composite specimens during processing using embedded fiber optic strain sensors and thermocouples. Extrinsic Fabry-Perot interferometer, Bragg grating strain sensors, and thermocouples were embedded in graphite/epoxy composite laminates prior to cure.
61780
Lawrence, C.M.; Nelson, D.V.; Spingarn, J.R.; Bennett,
T.E.
61173 Zhong, Y. Image segmentation for defect detection o n veneer surfaces Dissertation Abstracts International, Vol. 56, No. 6, 198 pp. (1995) (DA9535991) Nine algorithms covering three segmentation technique categories were explored. The performances of these nine algorithms were tested and compared under the combinations of two camera resolutions (5-but and 8bit), three color spaces (RGB, Lab, and gray-scale), and seven surface features (clear wood, blue stain, loose knot, pitch pocket, pitch streak, tight knot, and wane). Ten sample images for each of seven surface features on Douglas-fir veneer [Pseudotsuga menziesii] were used. Ten measures were proposed for performance evaluation. A multi- factor factorial ANOVA was used in the performance tests and comparisons.
61589 Lanza, F.; Geiger, F.; Wagner, V.; Visentini, L. Use of laser pulses to evaluate the resistance to t h e r m a l cycles of Z r O ( 2 ) t h e r m a l b a r r i e r o n gas t u r b i n e h a r d w a r e Commission of the Eun)pean Communities, EUR-15406-EN (1993) A thermal barrier formed by a layer of sprayed zirconia stabilised with yttria is largely used in the gas turbine components. The selection and qualification of the types of coatings has been made in the past using global tests. Simplified tests are commonly used just to obtain a comparative ranking between the different coatings. A test using laser shots having a duration time often milliseconds and a power of 2 kW/cm2 has been used to compare three different coatings. Single shots and series of 100 shots have been applied. The metallographic analysis of the different types of coatings after the tests allows information on their resistance to thermal fatigue to be obtained.
60748 Pepper, D.M. Nondestructive testing using n o n l i n e a r optically based s m a r t pixel processors Proceedings of an IEEE Conference on Nonlinear Optics. Material Fundamentals and Applications, Waikoloa (Hawaii), 25-29 Jul. 1994. pp. 265-268. IEEE (1994). ISBN 0780314735. There is an on-going need in the commercial sector to rapidly and nondestructively inspect components, ex situ and in situ, under harsh in-factory and field-testing conditions. To motivate this need, we cite below three such examples in rather diverse industrial applications. This will he followed by how optics and, more specifically, how so-called "smart-pixel processors," can augment existing inspection systems - all with the goal of enhancing the performance of the diagnostic. By smart-pixel processors, we imply that multi-pixelated information can be processed in parallel, with differential phase information preserved amongst the pixels. Typically, such processors can he realized via architectures involving phase-conjugate mirrors, either isolated, or in conjunction with spatial light modulators.
61582 Eisgruber, I.L.; Sites, J.R.; Matson, R.I.; Emergy, K.A. I n t e r p r e t a t i o n of laser scans from thin-film polycrystalline photovoltaic modules Proceedings of the Institute of Electrical and Electronics Engineers 1st World Conference on Photovoltaic Energy Conversion, Waikoloa, H! (United States), Vol. 1, 5-9 Dec. 1994. pp. 283-286. ISBN 078031459X Issues are addressed for thin film CdTe and CuinSesub(2) (CIS) modules and cells using a recently developed computer-controlled largescale laser scanner at the National Renewable Energy Laboratory (NREL). This instrument was designed to serve as a tool for research, device and module quality control, and module failure analysis. The thrust of the report is twofold: (i) the development of reliable submillimeter module characterization techniques and analysis and (2) presentation of the results of such techniques as applied to thin film CdTe and CIS modules.
60745 Frost, B.G.; van Hulst, N.F.; Lunedei, E.; Matteucci, G.; Rikkers, E. Study of the leakage field of magnetic force microscopy thin-film tips using electron holography Applied Physics Letters, Vol. 68, No. 13, pp. 1865-. (25 Mar. 1996) Electron holography is applied for the study of the leakage field of thin-film ferromagnetic tips used as probes in magnetic force microscopy. We used commercially available pyramidal tips covered on one face with a thin NiCo film, which were then placed in a high external magnetic field directed along the pyramid axis. Good agreement between simulated and experimental electron phase difference maps allows to measure the local flux from the ferromagnetic tips and therefore to evaluate the perturbation induced by the microprobe stray field on the sample area.
61366 Holt, M.S.; lyengar, R. T h e use of a n optical interference method to measure erosion rates of automotive d e a r c t m t s Society of Automotive Engineers, Paper No. 950798 (Jan. 1996) One important aspect of clearcoat degradation which affects interpretation of the results of ;~1 these methods is erosion. This paper will describe an accurate method for determining erosion rates by an optical interference method. This method will be used to demonstrate the effect of light stabilizers on erosion rate:~.
60531 Bradley, J. New technique for bore quality inspection Quality Testing Today, pp. 536-537 (Sep. 1995)
131