Definition of a new thermal contrast and pulse correction for defect quantification in pulsed thermography

2008 ◽  
Vol 51 (3) ◽  
pp. 160-167 ◽  
Author(s):  
Hernán D. Benítez ◽  
Clemente Ibarra-Castanedo ◽  
AbdelHakim Bendada ◽  
Xavier Maldague ◽  
Humberto Loaiza ◽  
...  
Keyword(s):  
Pulsed Thermography ◽  
Thermal Contrast ◽  
Definition Of ◽  
Pulse Correction ◽  
Defect Quantification

Defect Depth Quantification Using Pulsed Thermography

2012 ◽  
Vol 585 ◽  
pp. 72-76 ◽  
Author(s):  
D. Sharath ◽  
M. Menaka ◽  
B. Venkatraman
Keyword(s):  
Depth Estimation ◽  
Defect Size ◽  
Defect Depth ◽  
Pulsed Thermography ◽  
Full Field ◽  
First Derivative ◽  
Derivative Method ◽  
Aisi 316 ◽  
Materials Used ◽  
Defect Quantification

Pulsed Thermography is an advanced NDE technique which is becoming popular due to fast inspection rate, non contact nature and it gives full field image. Pulsed Thermography is successfully applied for defect detection, defect depth estimation, coating thickness evaluation and delamination detection in coatings but it is limited for evaluation of subsurface defects (of the order of few mm). In this paper we discuss the application of Pulsed Thermography for defect quantification and effect of defect size on it in AISI 316 grade SS which are important structural materials used in nuclear and other industries. Log First Derivative method is considered for defect depth quantification and the results are compared with Finite Difference Modeling carried out using ThermoCalc 6L software.

Defect quantification with reference-free thermal contrast and artificial neural networks

2007 ◽  
Author(s):  
Hernan D. Benitez ◽  
Clemente Ibarra-Castanedo ◽  
AbdelHakim Bendada ◽  
Xavier Maldague ◽  
Humberto Loaiza ◽  
...  
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Thermal Contrast ◽  
Artificial Neural ◽  
Defect Quantification

Relative Thermal Contrast Analysis in the Inspection of Wind Turbine Blades Using Pulsed Thermography

2011 ◽  
Vol 301-303 ◽  
pp. 591-596 ◽  
Author(s):  
Zhi Zeng ◽  
Ning Tao ◽  
Li Chun Feng ◽  
Ye Shu Li ◽  
Cun Lin Zhang
Keyword(s):  
Wind Turbine ◽  
Adhesive Bonding ◽  
Surface Defects ◽  
Turbine Blades ◽  
Direct Analysis ◽  
Air Bubbles ◽  
Wind Turbine Blades ◽  
Pulsed Thermography ◽  
Thermal Contrast ◽  
Reinforced Plastics

The rotor blade is an important component in wind turbine generator, it consists of glass fiber reinforced plastics (GFRP) and sandwich areas containing wood or plastic foam, different defects may be generated because of manufacturing problem. To improve the safety of wind turbine blades, pulsed thermography is being investigated in this study. Surface defects, such as air bubbles, edge bonding, etc. were easily and clearly detected on several full scale blades. Several specimens were manufactured to simulate the adhesive conditions between supporting spar and GFRP shells. The direct analysis of the original, 1stor 2ndderivatives was normally applied to judge any possible defects in the measured sample, and also used in quantitatively calculation. This study compared the relative thermal contrast (RTC) of the original and 1stderivative for air bubbles at shallow depth and deficiency adhesive bonding at deep depth, the calculation of the RTC could give us the approximate best time to analysis defects of different depth and types. The comparison also indicated that it is better to use the 1stderivative than the original to analysis the deep defects, however, there is no significant advantage in the analysis of shallow defects between the original and 1stderivative.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

2.2. Working Group 2: Conceptual Definitions of Reference Coordinate Systems for Earth Dynamics

1975 ◽  
Vol 26 ◽  
pp. 21-26
Keyword(s):  
Coordinate System ◽  
Working Group ◽  
General Character ◽  
Coordinate Systems ◽  
Reference Coordinate System ◽  
Group 2 ◽  
Definition Of ◽  
Earth Dynamics

An ideal definition of a reference coordinate system should meet the following general requirements:1. It should be as conceptually simple as possible, so its philosophy is well understood by the users.2. It should imply as few physical assumptions as possible. Wherever they are necessary, such assumptions should be of a very general character and, in particular, they should not be dependent upon astronomical and geophysical detailed theories.3. It should suggest a materialization that is dynamically stable and is accessible to observations with the required accuracy.

Symbiotic Stars at Optical, Infrared and Radio Wavelengths

1979 ◽  
Vol 46 ◽  
pp. 125-149 ◽  
Author(s):  
David A. Allen
Keyword(s):  
Temperature Regime ◽  
Type Star ◽  
Stellar Systems ◽  
Symbiotic Stars ◽  
Lower Excitation ◽  
Definition Of ◽  
Original Type

No paper of this nature should begin without a definition of symbiotic stars. It was Paul Merrill who, borrowing on his botanical background, coined the termsymbioticto describe apparently single stellar systems which combine the TiO absorption of M giants (temperature regime ≲ 3500 K) with He II emission (temperature regime ≳ 100,000 K). He and Milton Humason had in 1932 first drawn attention to three such stars: AX Per, CI Cyg and RW Hya. At the conclusion of the Mount Wilson Ha emission survey nearly a dozen had been identified, and Z And had become their type star. The numbers slowly grew, as much because the definition widened to include lower-excitation specimens as because new examples of the original type were found. In 1970 Wackerling listed 30; this was the last compendium of symbiotic stars published.

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