A method to determine wall thinning defect depths using the peak contrast slope method based on the transmission mode of pulsed IR thermography is presented. An analytical one-dimensional model of transient heat diffusion is used to deduce the proportionality factor between the time at peak contrast and the defect depth for a wide range of defect depths. The method has been corroborated with finite element model-based simulations. Experimental validation was carried out for four defect depths in steel. © 2010 Taylor & Francis.

Krishnan Balasubramaniam

Department of Mechanical Engineering

C V Krishnamurthy

Department Of Physics

DEFECT DEPTH

Experimental validations

Finite element models

IR thermography

One-dimensional model

PEAK CONTRAST SLOPE

PROPORTIONALITY FACTORS

PULSED THERMOGRAPHY

SLOPE METHOD

TRANSIENT HEAT DIFFUSION

TRANSMISSION MODE

WALL THINNING

Computer simulation

finite element method

THERMOGRAPHY (IMAGING)

Thermography (temperature measurement)

Defects

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Wall thinning defect estimation using pulsed IR thermography in transmission mode

Nondestructive Testing and Evaluation

In this paper, a novel way to inspect local wall thinning in metal tubes with infrared thermography has been demonstrated. The first of its kind method utilizes a periscope-like reflector located deep inside a tube to mirror the radiated heat that flows across the tube thickness to an IR camera positioned outside the tube. Localized wall thinning was represented by partially drilled holes of different depths on a tube, of inner diameter 82 mm and outer diameter 91 mm. Feasibility studies were carried out through simulations using a finite element model. Experiments were performed to determine the thermal diffusivity of the material. Remaining thicknesses of the tubes in wall-thinned sections were found to be estimated reasonably well using measured time-temperature profiles obtained by flash method [Parker WJ, Jenkins RJ, Butler CP, Abbott GL. Flash method of determining thermal diffusivity, heat capacity, and thermal conductivity. J Appl Phys 1961;32:1679-84]. The good correlation found between model calculations and measurements vindicated the utility of a model-based approach to applications of pulsed IR thermography. © 2009 Elsevier Ltd. All rights reserved.

NDT and E International

Periscope infrared thermography for local wall thinning in tubes

Journal of Applied Physics

Correction for Finite‐Pulse‐Time Effects in Very Thin Samples using the Flash Method of Measuring Thermal Diffusivity

Flash Method of Determining Thermal Diffusivity, Heat Capacity, and Thermal Conductivity

Journal	Nondestructive Testing and Evaluation
ISSN	10589759
Open Access	No