Abstract
The strain distribution along wood adhesive bonds was studied using a contact-free measurement system based on a white-light digital image correlation (DIC) technique. Two different specimen geometries and three different adhesives were investigated. The specimen geometries were according to the standards EN302-1 and ASTM D905. The adhesives tested were a phenolic resorcinol (PRF), a one-component polyurethane (PUR) and an epoxy (EPX). In addition to the experimental investigation, a finite element study using a non-linear fracture mechanics model for the adhesive bond line was carried out, aimed at investigating whether deformation measurements could predict differences in the mechanical behaviour of the adhesives. The measurement technique was found to be capable of distinguishing, in terms of their strain distributions at a given load, adhesives that differed markedly from one another. For example, the brittle PRF adhesive showed more localised strains than the more ductile EPX and PUR adhesives did at the same load level. Another conclusion from this study is that the measurement technique used is applicable to situations in which large strains occur. Thus, the technique used here is of great interest for use in the calibration of finite element models and constitutive theories and for the design of test set-ups.
References
ABAQUS Inc. (2003). ABAQUS/Standard and ABAQUS/CAE Version 6.4, Users Manuals.Search in Google Scholar
Adams, R.D., Ed. (2005) Adhesive Bonding. Science, Technology and Applications. Woodhead Publishing, Cambridge, UK.Search in Google Scholar
Aicher, S. (2003) Structural adhesive joints including glued-in bolts. In: Timber Engineering. Eds. Thelandersson, S., Larsen, H.J. John Wiley & Sons, Chichester, UK, pp. 333–363.Search in Google Scholar
Aicher, S., Klöck, W. (1990) Spannungsberechnungen zur Optimierung von Keilzinkenprofilen für Brettschichtholzlamellen. Bauen Holz92:356–362.Search in Google Scholar
Anon (2003) ASTM D905-03. Standard Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading. ASTM International.Search in Google Scholar
Anon (2004) EN 302-1. Adhesives for load-bearing timber structures-Test methods-Part 1: Determination of bond strength in longitudinal tensile shear strength.Search in Google Scholar
Gindl, W., Sretenovic, A., Vincenti, A., Müller, M. (2005) Direct measurement of strain distribution along a wood bondline. Part II. Effects of adhesive penetration on strain distribution. Holzforschung59:307–310.Search in Google Scholar
Kinloch, A.J. (1987) Adhesion and Adhesives. Science and Technology. Chapman and Hall, London.10.1007/978-94-015-7764-9Search in Google Scholar
Kollmann, F.F.P., Côté, W.A. (1968) Principles of Wood Science and Technology. Springer Verlag, Berlin.10.1007/978-3-642-87928-9Search in Google Scholar
Masuda, M. (1996) Application of the finite small area fracture criteria to bending of beams with end sloped notches. In: Proceedings of the International Wood Engineering Conference, New Orleans, LA, Vol. 4, pp. 136–143.Search in Google Scholar
Milner, H.R., Yeoh, E. (1991) Finite element analysis of glued timber finger joints. J. Struct. Eng.117(3):755–766.10.1061/(ASCE)0733-9445(1991)117:3(755)Search in Google Scholar
Müller, M., Sretenovic, A., Vincenti, A., Gindl, W. (2005) Direct measurement of strain distribution along a wood bondline. Part I. Shear strain concentration in a lap joint specimen by means of electronic speckle pattern interferometry. Holzforschung59:300–306.Search in Google Scholar
Samarasinghe, S., Kulasiri, D., Nicolle, K. (1996) Study of mode-I and mixed-mode fracture in wood using digital image correlation method. In: Proceedings of the International Wood Engineering Conference, New Orleans, LA, Vol. 4, pp. 144–151.Search in Google Scholar
Serrano, E. (2004) A numerical study of the shear-strength-predicting capabilities of test specimens for wood-adhesive bonds. Int. J. Adhes. Adhes.24:23–35.10.1016/S0143-7496(03)00096-4Search in Google Scholar
Serrano, E., Gustafsson, P.J. (1999) Influence of bondline brittleness and defects on the strength of timber finger-joints. Int. J. Adhes. Adhes.19:9–17.10.1016/S0143-7496(98)00048-7Search in Google Scholar
Wernersson, H. (1994) Fracture characterization of wood adhesive joints, PhD thesis, Report TVSM-1006. Division of Structural Mechanics, Lund University, Sweden.Search in Google Scholar
Zink, A.G. (1992) The influence of overlap length on the stress distribution and strength of a bonded wood double lap joint, PhD thesis. State University of New York, Syracuse, USA.Search in Google Scholar
Zink, A.G., Davidson, R.W., Hanna, R.B. (1995) Strain measurement in wood using a digital image correlation technique. Wood Fiber Sci.27:346–359.Search in Google Scholar
©2005 by Walter de Gruyter Berlin New York
