Holographic moiré in real time

• Published in: Experimental mechanics Vol. 22; no. 2; pp. 52 - 63
• Main Authors: SCIAMMARELLA, C.A, RASTOGI, P.K, JACQUOT, P, NARAYANAN, R
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-02-1982
• Subjects: Analysing. Testing. Standards; Applied sciences; Chemical and electrochemical properties; Exact sciences and technology; Industrial metrology. Testing; Measurement of properties and materials state; Measurement of surface state; Mechanical engineering. Machine design; Metals. Metallurgy; Nondestructive testing; Stress analysis; Theory; Utilisation; Comparisons; Optical holography; Concrete; Application; Comparative study; Moire pattern technique; Holography; Stress analysis
• ISSN: 0014-4851; 1741-2765
• DOI: 10.1007/BF02326077

The body of knowledge necessary to observe holographic-moire patterns in real time is introduced. The basic factors influencing fringe visibility in holographic moire are analyzed and expressions to evaluate fringe visibility for any given displacement and deformation are given. The application of the introduced theory in the case of real-time observation is discussed. It is shown that the max. benefits of this technique are achieved by combining it with closed-circuit TV. Several examples of application are given. A study of the evolution of cracks in a concrete beam subjected to four-point bending is presented. The tension side of a silicon carbide heat exchanger subjected to three-point bending and the crack tip of a 7075-T6 Al specimen subjected to modified wedge opening loading are studied. 26 ref.--AA