Investigation of the Micromechanics of the Microbond Test

Day, Richard and Cauich Rodrigez, J V (1998) Investigation of the Micromechanics of the Microbond Test.


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The microbond test is a method which is sometimes used for measuring interfacial shear strength. In the analysis of the data it is often assumed that the interfacial shear stress is constant and thus, by implication, that the strain in the fibre along the embedded fibre decreases linearly from the point of entry to the point of exit. In this paper the results of conventional microbond tests and simulated microbond tests performed under a Raman microscope on a Kevlar-49/epoxy system are reported. The conventionally performed tests show that the calculated interfacial shear strength for this system is approximately 16 MPa regardless of the position of the supporting knife edges. The strain distribution along the fibre during simulated microbond tests was studied as a function of knife edge position, interfacial area and level of load by means of Raman spectroscopy. It was found that the interfacial shear stress was not constant, as is frequently assumed, but was strongly dependent upon distance through the droplet, knife-edge position and applied load. At low loads the strain was a maximum at the point where the fibre entered the droplet and then dropped off sharply through the embedded length. This effect was enhanced when the knife-edge separation was reduced. The variation of the shape of the stress distribution was similar to that predicted by a linear finite element analysis. At higher load levels the onset of failure in the region closest to the point where the fibre entered the droplet could be observed.

Item Type: Article
Additional Information: Copyright © 1998 Elsevier. All rights reserved. This is the author's final version of the work after peer review. The article was originally published in Composites Science and Technology in 2008 by Elsevier. The full published article can be found at on the publisher's website
Keywords: aramid fibre, interface, interfacial strength, FEA, Raman spectroscopy
Divisions: ?? GlyndwrUniversity ??
Depositing User: ULCC Admin
Date Deposited: 22 May 2012 00:11
Last Modified: 11 Dec 2017 20:07

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