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Interpretation of optical caustic patterns obtained during unsteady crack growth: an analysis based on a higher-order transient expansion

Liu, Cheng and Rosakis, Ares J. (1991) Interpretation of optical caustic patterns obtained during unsteady crack growth: an analysis based on a higher-order transient expansion. In: Second International Conference on Photomechanics and Speckle Metrology. Proceedings of SPIE. No.1554. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, pp. 814-825. ISBN 9780819406828. https://resolver.caltech.edu/CaltechAUTHORS:20190221-110520782

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Abstract

The optical caustic method is re-examined considering the presence of transient effects. Based on the higher-order asymptotic expansion provided by Freund and Rosakis, regarding the stress field near a non-uniformly propagating crack tip, the caustic mapping and the initial curve equations are derived. The dynamic stress intensity factor, K^d_I(t), is related to experimentally measurable quantities of the caustic pattern by an explicit expression. It is shown that the classical analysis of caustics is a special case of the new interpretation method. The Broberg problem is used as an example problem to check the feasibility of analysing caustics in the presence of higher-order transient terms. It is shown that the caustic patterns are sensitive to transient effects, and that use of the classical analysis of caustics in the interpretation of the optical patterns for this problem may result in large errors in the value of the stress intensity factor, especially at short times after initiation.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.49532DOIArticle
Additional Information:© 1991 Society of Photo-Optical Instrumentation Engineers (SPIE).
Group:GALCIT
Series Name:Proceedings of SPIE
Issue or Number:1554
Record Number:CaltechAUTHORS:20190221-110520782
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190221-110520782
Official Citation:Cheng Liu and Ares J. Rosakis "Interpretation of optical caustic patterns obtained during unsteady crack growth: an analysis based on a higher-order transient expansion", Proc. SPIE 1554, Second International Conference on Photomechanics and Speckle Metrology, (1 December 1991); doi: 10.1117/12.49532; https://doi.org/10.1117/12.49532
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:93079
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:28 Feb 2019 23:48
Last Modified:03 Oct 2019 20:51

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