Skip to main content
SpringerLink
Log in

Fracture characterisation of green-glued polyurethane adhesive bonds in Mode I

  • Original Article
  • Published:
Materials and Structures Aims and scope Submit manuscript

Abstract

Unseasoned (green) spruce timber side boards of size 25 × 120 × 600 mm were flatwise-glued with a one-component PUR adhesive. Glued pairs of boards were then kiln-dried to 12 % moisture content. A special small-scale specimen for testing the fracture properties of the adhesive bond in Mode I was developed in order to evaluate the adhesive bond properties. The complete force versus deformation curve, including both the ascending and the descending parts, could be obtained with these small-scale specimens, enabling the strength and fracture energy of the bond line to be calculated. In addition, the fractured specimens were examined by scanning electron microscope. Results show that both the tensile strength and the fracture energy of the green glued PUR adhesive bonds were equal to those of the dry glued bonds. The methodology developed and used in the present study gives new possibilities for analysis of the mechanical behaviour of wood adhesive bonds, and particularly of their brittleness and its correlation with the type of fracture path. This is in sharp contrast to the use of standardised test methods (e.g. EN 302, ASTM D905) with specimens having relatively large glued areas. Using such types of specimens, it is not possible to obtain the complete force versus deformation response of the bond. In addition, when using such test methods, failure takes place in the wood or in the fibres near the bond, thus making it impossible to obtain detailed information about the bond line characteristics.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9

Similar content being viewed by others

References

  1. Anon (ASTM D 905-898) Standard test method for strength properties of adhesive bonds in shear by compression loading. Adhesives, vol 15.06. ASTM, Philadelphia

  2. Anon (EN 302-1:2004) Adhesives for load bearing timber structures. Test methods. Determination of bond strength in longitudinal tensile shear strength. European Committee for Standardization (CEN), Brussels

  3. Baba MN (2011) Assessing the mode i interlaminar fracture toughness of wood laminated specimens—an experimental approach. Pro Ligno 7(3):10–17

    Google Scholar 

  4. Bergman RD, Simpson WT, Turk C (2010) Evaluating warp of 2 by 4 s sawn from panels produced through green gluing dimension lumber from small ponderosa pine logs. For Prod J 60(1):57–63

    Google Scholar 

  5. Boström L (1992) Method for determination of the softening behaviour of wood and the applicability of a nonlinear fracture mechanics model. Dissertation no TVBM-1012, Lund Institute of Technology, Division of Building Materials, Lund, Sweden

  6. Conrad MPC, Smith GD, Fernlund G (2004) Fracture of wood composites and wood-adhesive joints: a comparative review. Wood Fiber Sci 36:26–39

    Google Scholar 

  7. Core Document of the COST Action E34 Bonding of Timber (2008) In: Dunky M, Källander B, Properzi M, Richter K, Van Leemput M (eds) WG 2 Green gluing. ISSN 1681-2808

  8. da Silva LFM, de Magalhaes F, Chaves FJP, de Moura M (2010) Mode II fracture toughness of a brittle and a ductile adhesive as a function of the adhesive thickness. J Adhes 86(9):889–903

    Google Scholar 

  9. de Moura M, Oliveira JMQ, Morais JJL, Dourado N (2011) Mixed-mode (I plus II) fracture characterization of wood bonded joints. Constr Build Mater 25(4):1956–1962

    Article  Google Scholar 

  10. Gagliano JM, Frazier CE (2001) Improvements in the fracture cleavage testing of adhesively-bonded wood. Wood Fiber Sci 33(3):377–385

    Google Scholar 

  11. Gustafsson PJ, Enquist B (1988) Strength of wooden beam at right angle notch. Report TVSM-7042, Lund Institute of Technology Division of Structural Mechanics (in Swedish)

  12. Hilleborg A (1991) Application of the fictitious crack model to different types of materials. Int J Fract 51:95–102

    Google Scholar 

  13. Holmberg S (1998) A numerical and experimental study of initial defibration of wood. Dissertation No TVSM-1010, Lund Institute of Technology Division of Structural Mechanics, Lund, Sweden

  14. Li Y-N, Bažant ZP (1994) Eigenvalue analysis of size effect for cohesive crack model. Int J Fract 66(3):213–226

    Article  Google Scholar 

  15. Li S, Thouless MD, Waas AM, Schroeder JA, Zavattieri PD (2005) Use of Mode-I cohesive-zone models to describe the fracture of an adhesively-bonded polymer-matrix composite. Compos Sci Technol 65:281–293

    Article  Google Scholar 

  16. Li S, Thouless MD, Waas AM, Schroeder JA, Zavattieri PD (2006) Competing failure mechanisms in mixed-mode fracture of an adhesively bonded polymer-matrix composite. Int J Adhes Adhes 26:609–616

    Article  Google Scholar 

  17. Marzi S, Biel A, Stigh U (2011) On experimental methods to investigate the effect of layer thickness on the fracture behavior of adhesively bonded joints. Int J Adhes Adhes 31(8):840–850

    Article  Google Scholar 

  18. Maun K, Cooper G (1999) Re-engineering softwood for constructional use by wet (green) gluing. In: Berti S, Macchioni N, Negri M, Rachello E (eds) Eurowood technical workshop proceedings industrial end-uses of fast-grown species, Florence May 31st–June 1st, pp 47–59

  19. Ormstad E (2005) Gluing sideboards from green Norway spruce. In: Källander B (ed) Proceedings of international conference/workshop green gluing of wood—process—products—market, Borås, April 7–8, 2005, pp 113–117

  20. Petersson H, Källsner B, Ormarsson S (2005) Shape stability of laminated planks made of green-glued pairs of side boards. In: Källander B (ed) Proceedings of international conference/workshop green gluing of wood—process—products—market. Borås, April 7–8, 2005, pp 118–124

  21. Pommier R, Elbez G (2006) Finger-jointing green softwood: evaluation of the interaction between polyurethane adhesive and wood. Wood Mater Sci 1:127–137

    Article  Google Scholar 

  22. Properzi M, Pizzi A (2003) Comparative wet wood gluing performance of different types of glulam wood adhesives. Holz als Roh- und Werkstoff 61:77–78

    Article  Google Scholar 

  23. Seltman J (1995) Freilegen der Holzstruktur duch UV-Bestrahlung. Holz Roh Werkst 53:225–228

    Article  Google Scholar 

  24. Serrano E (2000) Adhesive joints in timber engineering. Modelling and testing of fracture properties. Dissertation Report TVSM-1012, Lund University, Department of Mechanics and Materials, Structural Mechanics. Lund, Sweden

  25. Serrano E (2001) Glued-in rods for timber structures. An experimental study of softening behaviour. Mater Struct 34(238):228–234

    Article  Google Scholar 

  26. Serrano E (2004) A numerical study of the shear-strength-predicting capabilities of test specimens for wood-adhesive bonds. Int J Adhes Adhes 24(1):23–35

    Article  Google Scholar 

  27. Serrano R, Cassens D (2001) Reducing warp and checking in plantation-grown yellow-poplar 4 by 4’s by reversing part positions and gluing in the green condition. For Prod J 51(11/12):37–40

    Google Scholar 

  28. Serrano E, Enquist B (2005) Contact-free measurement and non-linear element analyses of strain distribution along wood adhesive bonds. Holzforschung 59:641–646

    Article  Google Scholar 

  29. Serrano E, Gustafsson PJ (2006) Fracture mechanics in timber engineering—strength analyses of components and joint. Mater Struct 40:87–96

    Article  Google Scholar 

  30. Shipsha A, Berglund LA (2007) Shear coupling effects on stress and strain distributions in wood subjected to transverse compression. Compos Sci Technol 67:1362–1369

    Article  Google Scholar 

  31. Simon F, Valentin G. (2000) In: Williams JG, Pavan A (eds) Damage and fracture of wood adhesive bonded joints under shear and opening loading, vol 27. European Structural Integrity Society, Elsevier, pp 285–296

  32. Simon F, Valentin G (2003). In: Blackman RK, Williams JG, Pavan A (eds) Cohesive failure characterisation of wood adhesive joints loaded in shear, vol 32. European Structural Integrity Society, Elsevier, pp 305–316

  33. Singh HK, Chakraborty A, Frazier CE, Dillard DA (2010) Mixed mode fracture testing of adhesively bonded wood specimens using a dual actuator load frame. Holzforschung 64(3):353–361

    Article  Google Scholar 

  34. Sterley M (2004) Green gluing of wood. Licentiate thesis. KTH Stockholm, Sweden. ISBN 91-7283-711-X

    Google Scholar 

  35. Sterley M, Gustafsson PJ (2005) Shear fracture properties of green-glued polyurethane wood adhesive bonds. In: Frihart Ch R (ed) Proceedings No 7230 of wood adhesives 2005, pp 221–229

  36. Sterley M, Serrano E, Enquist B (2008) Fracture characterisation of green glued polyurethane adhesive bonds in Mode I. In: Csiha C (ed) Proceedings of final conference in COST action E34 bonding timber; enhancing bondline performance, pp 156–166. Sopron, Hungary, 6–7 May

  37. Sterley M, Serrano E, Enquist B (2009) Flat wise green gluing of Norway spruce for structural application. In: Proceedings of the international conference on wood adhesives, Lake Tahoe, Nevada, USA, September 28–30

  38. Sterley M, Trey S, Lundevall Å, Olsson S (2012) Influence of cure conditions on the properties of a one component moisture cured polyurethane adhesive in the context of green gluing of wood. J Appl Polym Sci. doi:10.1002/app.36895

  39. Stigh U, Alfredsson KS, Andersson T, Biel A, Carlberger T, Salomonsson K (2010) Some aspects of cohesive models and modelling with special application to strength of adhesive layers. Int J Fract 165(2):149–162

    Article  MATH  Google Scholar 

  40. Veigel S, Follrich J, Gindl-Altmutter W, Müller U (2012) Comparison of fracture energy testing by means of double cantilever beam-(DCB)-specimens and lap joint testing method for the characterization of adhesively bonded wood. Eur J Wood Wood Prod 70(1–3):3–10

    Article  Google Scholar 

  41. Wernersson H (1994) Fracture characterisation of wood adhesive joints. Dissertation TVSM 1006. Lund Institute of Technology Division of Structural Mechanics, Sweden

  42. Xavier J, Morais J, Dourado N, de Moura M (2011) Measurement of Mode I and Mode II fracture properties of wood-bonded joints. J Adhes Sci Technol 25(20):2881–2895

    Google Scholar 

Download references

Acknowledgments

The financial support from the Foundation Centre for Building and Living with Wood (CBBT) and from the Knowledge Foundation (KK-stiftelsen), which made this research possible, is hereby gratefully acknowledged.

Author information

Authors and Affiliations

  1. SP Technical Research Institute of Sweden, Box 5609, 114 86, Stockholm, Sweden

    Magdalena Sterley & Erik Serrano

  2. Linnaeus University, 351 95, Växjö, Sweden

    Magdalena Sterley, Erik Serrano & Bertil Enquist

Authors
  1. Magdalena Sterley
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Erik Serrano
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Bertil Enquist
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Magdalena Sterley.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Sterley, M., Serrano, E. & Enquist, B. Fracture characterisation of green-glued polyurethane adhesive bonds in Mode I. Mater Struct 46, 421–434 (2013). https://doi.org/10.1617/s11527-012-9911-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1617/s11527-012-9911-5

Keywords

Search

Navigation