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Advances in Materials Science and Engineering
Volume 2017, Article ID 5637248, 11 pages
Research Article

Adhesive Through-Reinforcement Improves the Fracture Toughness of a Laminated Birch Wood Composite

1Centre for Advanced Wood Processing, University of British Columbia, 2424-2900 Main Mall, Vancouver, British Columbia, Canada V6T 1Z4
2Department of Applied Mathematics, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia

Correspondence should be addressed to Wenchang He; moc.liamg@yrotcivneweh

Received 14 July 2016; Revised 21 December 2016; Accepted 4 January 2017; Published 23 January 2017

Academic Editor: Peter Chang

Copyright © 2017 Wenchang He and Philip D. Evans. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this paper we test the hypothesis that adhesive through-reinforcement in combination with glass-fibre reinforcement of adhesive bond lines will significantly improve the fracture toughness of a laminated birch wood composite. We test this hypothesis using a model composite consisting of perforated veneer that allowed a polyurethane adhesive to penetrate and reinforce veneers within the composite. Model composite specimens were tested for mode I fracture properties, and scanning electron microscopy was used to examine the microstructure of fracture surfaces. Our results clearly show that through-reinforcement, and also reinforcing adhesive bond lines with glass-fibre, significantly improved fracture toughness of the birch wood composite. Our results also indicate that improvements in fracture toughness depended on the level of reinforcement. Improvements in fracture toughness were related to the ability of the reinforcement to arrest crack development during fracture testing and the fibre bridging effect of glass-fibre in adhesive bond lines. We conclude that through-reinforcement is an effective way of improving the fracture toughness of laminated wood composites, but further research is needed to develop practical ways of creating such reinforcement in composites that more closely resemble commercial products.