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Tunneling radial cracks in layered structures from contact loading

Chai, Herzl and Ravichandran, Guruswami (2009) Tunneling radial cracks in layered structures from contact loading. Engineering Fracture Mechanics, 76 (16). pp. 2526-2537. ISSN 0013-7944.

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Glass/epoxy laminates glued onto a compliant substrate are indented with a hard ball. The damage is characterized by a set of transverse cracks which pop out from the subsurface of the glass layers due to flexure and propagate stably in the radial direction with load in a bell-shape front under a diminishing stress field. Compliant interlayers, even extremely thin ones, are effective in inhibiting crossover fracture. This leads to crack tunneling and crack multiplication in the hard layers, which enhances energy dissipation and reduces the spread of damage relative to the basic bilayer configuration. The experiments show that the fracture in a given layer is well approximated by a power-law relation of the form c^(3/2)K_C/P = δ, where P, c, and K_C are the indentation load, crack length and fracture toughness, in that order, and δ an implicit function of the layer position and material and geometric variables, derived with the aid of available tunnel crack solutions. The model specimen studied provides a useful insight into the fracture behavior of natural, biological and synthetic layered structures from concentrated loading. The analysis shows that the crack arrest capability of a thin interlayer increases in proportion to the modulus misfit ratio between the layer and interlayer, and that the spread of radial cracks in a laminate of given thickness reduces in proportion to n^(1/3), where n is the number layers in the laminate.

Item Type:Article
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Ravichandran, Guruswami0000-0002-2912-0001
Additional Information:© 2009 Elsevier Ltd. Received 14 June 2009; revised 24 August 2009; accepted 1 September 2009. Available online 6 September 2009. We gratefully acknowledge the support of the DoD MURI at the California Institute of Technology on Mechanics and Mechanisms of Impulse Loading, Damage and Failure of Marine Structures and Materials through the Office of Naval Research (Grant #N00014-06-1-0730, Dr. Y.D.S. Rajapakse, Program Manager).
Funding AgencyGrant Number
Office of Naval ResearchN00014-06-1-0730
Subject Keywords:Indentation; Multilayer; Glass; Radial cracks; Tunneling cracks
Issue or Number:16
Record Number:CaltechAUTHORS:20100104-110227189
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Official Citation:Herzl Chai, Guruswami Ravichandran, Tunneling radial cracks in layered structures from contact loading, Engineering Fracture Mechanics, Volume 76, Issue 16, November 2009, Pages 2526-2537, ISSN 0013-7944, DOI: 10.1016/j.engfracmech.2009.09.001. (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17046
Deposited By: Tony Diaz
Deposited On:05 Jan 2010 17:20
Last Modified:09 Mar 2020 13:19

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