Observation of crack closure using a crack mouth opening displacement gauge

Brahma, KK and Dash, PK and Dattaguru, B (1989) Observation of crack closure using a crack mouth opening displacement gauge. In: International Journal of Fatigue, 11 (1). pp. 37-41.

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Abstract

A crack mouth opening displacement (CMOD) gauge has been designed to estimate the crack length as well as the crack opening stress level in an automated fatigue crack propagation test programme. The CMOD gauge accurately predicts crack tip opening levels in K-controlled tests with constant K, K increasing or K decreasing. In all three K-controlled tests with a single 100% overload cycle, the CMOD gauge does not measure the crack tip opening stress level over a large range of crack lengths after the application of the overload. The CMOD gauge measures the stress level at which the overload plastic zone site opens. Caution should thus be exercised in using the crack opening stress level, estimated by the CMOD gauge, to explain fatigue crack propagation under arbitrary load sequences from the viewpoint of crack closure phenomena.

Item Type:	Journal Article
Publication:	International Journal of Fatigue
Publisher:	Elsevier science
Additional Information:	Copyright of this article belongs to Elsevier science.
Keywords:	Fatigue crack closure;opening stress;crack mouth opening displacement gauge;K-controlled FCP test;overload.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	19 Oct 2010 08:52
Last Modified:	19 Oct 2010 08:52
URI:	http://eprints.iisc.ac.in/id/eprint/33238

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