HOLOGRAPHIC QUANTITATIVE NON-DESTRUCTIVE EVALUATION (NDE)
A. V. S. S. S. R. Sarma, P. S. Mani, S. A. Pillai, V. R. Ravindran and K. V. Rajendran
Vikram Sarabhai Space Centre, Thiruvananthapuram 695 022, India
Keywords: Holography; low-modulus; image processing; debonds; tight cracks
ABSTRACT The efficacy of holography for quantitative NDE was shown for low modulus materials [1, 2]. Low modulus materials have inherent damping property and due to this effect, the rigid body disturbances during holography are minimal or absent. For metallic materials however, these rigid body movements invariably occur affecting the sensitivity of the technique in addition to making the evaluation process difficult. There is a requirement of NDE for example in diffusion type of platting or coatings where ultrasonic techniques cannot be used because of restriction of usage of couplant fluids and radiography has limitation with respect to debonds and tight cracks. The potentiality of holography in such cases is studied using metallic specimens taking care to see that the rigid body movements are minimal. Quantification of defects is attempted using image processing. The potentiality of holography for quick initial identification of critically strained zones and quantitative evaluation of defects is demonstrated using the experimental data for rectangular metallic specimens and pressure bottles. REFERENCES
- V. R. Ravindran, A. V. S. S. S. R. Sarma and V. Unnikrishnan Nair, "Holographic Nondestructive Testing of Low-Modulus Materials", Material Evaluation 50(9), 1058-1065 (1993)
- V. R. Ravindran, A. V. S. S. S. R. Sarma and V. Unnikrishnan Nair, "Holographic Nondestructive Testing (HNDT) of Low-Modulus Materials using Bending Load", The British Journal of NDT 35(8), 429-432 (1993)
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 3, pages 1503 - 1506
Publisher: Ashgate Publishing Company
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