On the evaluation of energy release rate and mode mixity for ductile asymmetric four point bend specimens

Vaishakh, K V and Narasimhan, R (2019) On the evaluation of energy release rate and mode mixity for ductile asymmetric four point bend specimens. In: INTERNATIONAL JOURNAL OF FRACTURE, 217 (1-2). pp. 65-82.

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Abstract

A method for evaluating the contributions from mode I and II components of loading to the energy release rate J in ductile asymmetric four-point bend (4-PB) specimens is proposed. The validity of the method is established by conducting elastic-plastic finite element analysis of several asymmetric 4-PB specimens exhibiting a range of mode mixities from pure mode I to II and having different crack length to width (a/W) ratios. Further, a definition of plastic mode mixity is introduced based on the near-tip opening and sliding displacements. This definition and the proposed method to evaluate J are easy to apply since the required crack opening and sliding displacements can be determined from in-situ optical imaging coupled with Digital Image Correlation (DIC) technique. The application of the proposed methodology is demonstrated by analyzing mixed-mode fracture experiments being conducted with a magnesium alloy. It is found that the critical value of J at crack initiation reduces as loading changes from mode I to II.

Item Type:	Journal Article
Publication:	INTERNATIONAL JOURNAL OF FRACTURE
Publisher:	SPRINGER
Additional Information:	copyright for this article belongs to SPRINGER
Keywords:	Asymmetric four-point bend specimen; Energy release rate; Mode mixity; Finite element analysis; Digital image correlation
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	29 Aug 2019 10:07
Last Modified:	29 Aug 2019 10:07
URI:	http://eprints.iisc.ac.in/id/eprint/63334

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