Nondestructive evaluation of materials by infrared thermography

Nondestructive evaluation of materials by infrared thermography

N DT Abstracts small inserts of various electrical conductivities and different sizes, located at different depths in composite materials samples. It ...

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N DT Abstracts small inserts of various electrical conductivities and different sizes, located at different depths in composite materials samples. It was possible to detect electrical conductivity differences between the inserts and the bulk material ranging from a few omegam to 10 omegam/sup-1/, at depths of a few millimeters, depending on the ratio between the two conductivities. A quantitative validation of the method was done by comparing experimental temperature images obtained by the infrared camera and theory. A quite good agreement was obtained, in particular with highly conductive defects.

This book presents an up to date coverage of infrared thermography applied in the context of improved industrial activity and quality through automated inspection control. Particular emphasis is given to thermal methods, image processing and quantitative characterisation. Every subject covered is illustrated with industrial applications. All concepts are thoroughly explained. 52781 Kaasinen,H. Assessing the quality of the waterproofing of bridges using thermography

53812 Hot Stuff. High definition thermography aids research into

British Journal of Nondestructive Testing, Vol. 35, No. 6, pp. 301-304 (Jun. 1993) Studies performed both in the laboratory and on two ~st bridges indicate that infrared thermography appears to be applicable for assessing the adhesion of waterproofing sheet membranes on the site of bridge works. The method can be used to Iocalise those areas in which a waterproofing sheet membrane is defectively attached or completely detached from the substrate. The method makes it possible to obtain quickly a mainly general picture of adhesion, so infrared thermography and adhesive strength measurement are methods which complement one another very well.

plastic processing Quality Today, pp. 32-34 (Nov. 1993) High definition infrared thermography techniques have been used as an aid to research. New processing technologies studying various raw materials have been research. A high definition Thermovision 700 thermo imaging camera is used to look at the effects of temperature in the development of infected and blow moulded technical parts and extruded pipes.

Luong, M.P. Infrared thermographic scanning of fatigue in metals 53555

12th International Conference on Structural Mechanics in Reactor Technology, Stuttgart (Germany), 15-20 Aug. 1993. Vol. G, pp. 219-224. Edited by K.F. Kussmaul. International Association for Structural Mechanics in Reactor Technology, e.V. (1993) ISBN 0444815155 This paper aims to illustrate the use of infrared thermography as a nondestructive, in real time and noncontact technique (a) to observe the physical processes of damage and fatigue on metallic specimens subjected to rotating bending Ioadings, (b) to detect the occurrence of energy dissipation and (c) to evaluate the limit of endurance of the tested materials. In addition, this infrared thermographic technique describes the location and process of the material damage.

Gayo, E.; Palomo, A., Macias, A. Infrared thermography as a tool for studying the movement of water through some building materials - P a r t 1: capillary moisture 52300

European Journal of Non-Destructive Testing, Vol. 2, No. 4, pp. 159- 166 (Apr. 1993) The objective of the present work is to show the usefulness of infrared thermography for identifying moisture in building materials. In the first of a planned series of experiments, different materials have been subjected to cycles of suction using water at 20C and 40C. An evaluation of capillarity suction, surface temperature and emissivity of materials has been carried out with the aid of the infrared technique. Emissivity, which is a characteristic property of each material, depends on the water content of the material. In addition it is observed that the temperature of the water influences the suction process. This knowledge give investigators an opportunity of diagnosing the hygrothermal behaviour of construction materials in buildings without the need for destructive tests.

Gayo, E.; Palomo, A.; Macias, A. Infrared thermography as a tool for studying the movement of w a t e r through some building materials. P a r t I h evaporation process 53554

European Journal of Non-Destructive Testing, Vol. 3, No. 2, pp. 55-58 (Oct. 1992) In this series of experiments some different building materials have been subjected to cycles of evaporation with water at different temperatures. The evaluation of the evaporation process, surface temperature and emissivity of materials has been carried out, as in the first series of experiments, with the aid of an infrared technique. Infrared thermography has been shown to be valuable technique for establishing relationships between relative humidity, room temperature and moisture content.

52031 Weil,G.J., GraJ; R.J. Infrared thermography based pipeline leak detection Civil Engineering Applications of Remote Sensing and Geographic Information Systems, Washington, D.C. (United States), 14-16 May 1991. pp. 189-198. Edited by D.B. Stafford. American Society of Civil Engineers (1991) Computerized Infrared Thermographic pipeline inspection is now a refined and reliable process. The process has been used to test pipelines in chemical plants, water supply systems, steam lines, natural gas pipelines and sewer systems. Its non-contact, non- destructive ability to inspect large areas from above ground with 100% coverage and to locate subsurface leaks as well as the additional capability to locate voids and erosion surrounding pipelines make its testing capabilities unique. This paper will detail the development of computerized infrared thermographic pipeline testing along with case histories illustrating its implementation, problems and successes.

Jones, T.S.; Berger, H.; Weaver, E. Large area thermugraphic inspection of GRP composite marine vessel hulls 53247

Thermosense XV International Conference on Thermal Sensing and Imaging Diagnostic Applications, Orlando, Florida (United States), 14-16 Apr. 1993. pp. 197-206. Edited by L.R. Allen. SPIE. Vol. 1933 (1993) The study demonstrated the ability of infrared thermography to detect hidden flaws through a variety of laminates and sandwich panel core materials. Empirical results matched well with analytical results of the sensitivity of the technique to various sizes of discontinuities at different depths. The infrared method offers sensitive, fast, large area, and noncontact inspection.

Connolly,M.P. The measurement of porosity in composite materials using infrared thermography 51779

Journal of Reinforced Plastics and Composites, Vol. 2, No. 12, pp. 1367-1375 (Dec. 1992) An infrared thermographic technique is described here, which can be used to determine the degree of porosity in polymeric matrix composile materials. The technique consists of heating one face of the part with a high power laser and observing the thermal response on the other face as the beat diffuses through the part. Internal defects such as porosity modify the apparent diffusivity and reduce the rate and quantity of heat transferred to the opposite face. Experiments were conducted on carbon-epoxy samples with a range of known porosities and varying thicknesses and the thermal response was measured. The results show that for the high porosity samples smaller temperature rises, with longer times to reach the maximum were observed on the opposite face. An analysis of the heat transfer through the samples is presented and this analysis shows how the thermal diffusivity influences the temperature rise observed on the opposite face. The results from this analysis were used to interpret the experimental thermal response in terms of an apparent diffusivity and a good correlation was obtained between the diffusivity and the porosities for the samples tested.

53054 Anon Infrared thermography guide (revision 1) Electric Power Research, Institute, Palo Alto, California (United States), NP-6973, Rev. I, 252pp. (Dec. 1992) Infrared thermography (IR) uses nonintrusive techniques to monitor the operating condition of equipment and components. This revised report provides updated information to assist utilities in implementing an effective IR program. 53051 Maldague, X.P.V. Nondestructive Evaluation Thermography.

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Springer-Verlag, 207pp. (1993). ISBN 0-387-19769-9

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