Pulsed thermography is an effective technique for quantitative prediction of defect depth within a specimen. Several methods have been reported in the literature. In this paper, using an analysis based on a theoretical one-dimensional solution of pulsed thermography, we analyzed four representative methods. We show that all of the methods are accurate and converge to the theoretical solution under ideal conditions. Three methods can be directly used to predict defect depth. However, because defect features that appear on the surface during a pulsed thermography test are always affected by three-dimensional heat conduction within the test specimen, the performance and accuracy of these methods differs for defects of various sizes and depths. This difference is demonstrated and evaluated from a set of pulsed thermography data obtained from a specimen with several flat-bottom holes as simulated defects.
Issue Section:
Experimental Techniques
1.
Verrilli
, M. J.
, Ojard
, G.
, Barnett
, T. R.
, Sun
, J. G.
, and Baaklini
, G.
, 2002, “Evaluation of Post-exposure Properties of SiC∕SiC Combustor Liners Tested in the RQL Sector Rig
,” Ceram. Eng. Sci. Proc.
0196-6219, 23
(3
), pp. 551
–562
.2.
Sun
, J. G.
, Verrilli
, M. J.
, Stephan
, R.
, Barnett
, T. R.
, and Ojard
, G.
, 2002, “Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components
,” Rev. Prog. Quant. Nondestr. Eval.
0743-0760, 22
, pp. 1011
–1018
.3.
Busse
, G.
, 1979, “Optoacoustic Phase Angle Measurement for Probing a Metal
,” Appl. Phys. Lett.
0003-6951, 35
, pp. 759
–760
.4.
Busse
, G.
, Wu
, D.
, and Karpea
, W.
, 1992, “Thermal Wave Imaging With Phase Sensitive Modulated Thermography
,” J. Appl. Phys.
0021-8979, 71
, pp. 3962
–3965
.5.
Parker
, W. J.
, Jenkins
, R. J.
, Butler
, C. P.
, and Abbott
, G. L.
, 1961, “Flash Method of Determining Thermal Diffusivity, Heat Capacity, and Thermal Conductivity
,” J. Appl. Phys.
0021-8979, 32
, pp. 1679
–1684
.6.
Heckman
, R. C.
, 1973, “Finite Pulse Time and Heat-Loss Effects in Pulsed Thermal Diffusivity Measurements
,” J. Appl. Phys.
0021-8979, 44
, pp. 1455
–1460
.7.
Tang
, D. W.
, He
, G. H.
, and Zhou
, B. L.
, 1995, “Effects of Finite Absorption Depth and Infrared Detector Non-linearity on Thermal Diffusivity Measurement of Thin Films Using the Flash Method
,” Rev. Sci. Instrum.
0034-6748, 66
, pp. 4249
–4253
.8.
Deemer
, C.
, Sun
, J. G.
, Ellingson
, W. A.
, and Short
, S.
, 1999, “Front-Flash Thermal Imaging Characterization of Continuous Fiber Ceramic Composites
,” Ceram. Eng. Sci. Proc.
0196-6219, 20
(3
), pp. 317
–324
.9.
Ringermacher
, H. I.
, Archacki
, Jr., R. J.
, and Veronesi
, W. A.
, 1998, “Nondestructive Testing: Transient Depth Thermography
,” U.S. Patent No. 5,711,603.10.
Han
, X.
, Favro
, L. D.
, Kuo
, P. K.
, and Thomas
, R. L.
, 1996, “Early-Time Pulse-Echo Thermal Wave Imaging
,” Rev. Prog. Quant. Nondestr. Eval.
0743-0760, 15
, pp. 519
–524
.11.
Maldague
, X.
, 1993, Nondestructive Evaluation of Materials by Infrared Thermography
, Springer
, New York.12.
Shepard
, S. M.
, Lhota
, J. R.
, Rubadeux
, B. A.
, Wang
, D.
, and Ahmed
, T.
, 2003, “Reconstruction and Enhancement of Active Thermographic Image Sequences
,” Opt. Eng.
0091-3286, 42
, pp. 1337
–1342
.13.
Sun
, J. G.
, 2003, “Method for Determining Defect Depth Using Thermal Imaging
,” U.S. Patent No. 6,542,849.14.
Roth
, D. J.
, Bodis
, J. R.
, and Biship
, C.
, 1997, “Thermographic Imaging for High-Temperature Composite Materials—A Defect Detection Study
,” Res. Nondestruct. Eval.
0934-9847, 9
, pp. 147
–169
.15.
Avdelidis
, N. P.
, and Almond
, D. P.
, 2004, “Through Skin Sensing Assessment of Aircraft Structures Using Pulsed Thermography
,” NDT & E Int.
0963-8695, 37
, pp. 353
–359
.16.
Meola
, C.
, Calomagno
, G. M.
, and Giorleo
, L.
, 2004, “Geometrical Limitations to Detection of Defects in Composites by Means of Infrared Thermography
,” J. Nondestruct. Eval.
0195-9298, 23
, pp. 125
–132
.17.
Martin
, R. E.
, and Gyekenyesi
, A.
, 2002, “Pulsed Thermography of Ceramic Matrix Composites
,” Proc. SPIE
0277-786X, 4704
, pp. 82
–92
.18.
Cernuschi
, F.
, Bison
, P. G.
, Figari
, A.
, Marinetti
, S.
, and Grinzato
, E.
, 2004, “Thermal Diffusivity Measurements by Photothermal and Thermographic Technologies
,” Int. J. Thermophys.
0195-928X, 25
, pp. 439
–457
.19.
Sun
, J. G.
, and Erdman
, S.
, 2003, “Effect of Finite Flash Duration on Thermal Diffusivity Imaging of High-Diffusivity or Thin Materials
,” Rev. Prog. Quant. Nondestr. Eval.
0743-0760, 23
, pp. 482
–487
.20.
Sun
, J. G.
, and Benz
, J.
, 2004, “Flash Duration Effect in One-Sided Thermal Imaging
,” Rev. Prog. Quant. Nondestr. Eval.
0743-0760, 24
, pp. 650
–654
.21.
Sun
, J. G.
, Deemer
, C.
, Ellingson
, W. A.
, Easler
, T. E.
, Szweda
, A.
, and Craig
, P. A.
, 1999, “Thermal Imaging Measurement and Correlation of Thermal Diffusivity in Continuous Fiber Ceramic Composites
,” Therm. Conduct.
0163-9005, 24
, pp. 616
–622
.22.
Vavilov
, V.
, Maldague
, X.
, Dufort
, B.
, Robitaille
, F.
, and Picard
, J.
, 1993, “Thermal Nondestructive Testing of Carbon Epoxy Composites: Detailed Analysis and Data Processing
,” NDT & E Int.
0963-8695, 26
(2
), pp. 85
–95
.23.
ASTM Standard E1461-92, 1992, “
Standard Test Method for Thermal Diffusivity of Solids by the Flash Method
,” American Society of Testing of Materials
, Philadelphia.Copyright © 2006
by American Society of Mechanical Engineers
You do not currently have access to this content.
