Blog List

Friday 28 October 2016

Mixed mode fracture of glued-in rods in timber structures

Published Date
Original Paper
DOI: 10.1007/s10704-014-9986-9


Cite this article as: 
Lartigau, J., Coureau, JL., Morel, S. et al. Int J Fract (2015) 192: 71. doi:10.1007/s10704-014-9986-9


Author

  • Julie Lartigau
  • Email author
  • Jean-Luc Coureau
  • Stéphane Morel
  • Philippe Galimard
  • Emmanuel Maurin


  • Abstract


    Glued-in-rods in timber structures lead to overcome the use of traditional bolted connections, preserve a large part of the original timber and offer aesthetic benefits. Several research programs were achieved to improve the mechanical knowledge of this technique, exhibiting experimentally the influence of materials and the effect of the geometric configuration. From these experimental results, some design rules predicting the axial strength are available, but a common criterion is still lacking. This paper relates to experimental investigations and finite element computations on glued-in rods, with the aim of providing a better knowledge about their mechanical behavior until failure. An experimental campaign is carried out on single glued-in rod connections. The finite element modeling reproduces the experimental configuration: it exhibits significant normal stress (to the interface) at the onset of the bonding, in comparison with shear stress. Within the framework of equivalent linear elastic fracture mechanics, resistance curves in mode I and mode II are established for each specimen. Finally, a mixed mode fracture criterion (I/II) is used to describe the fracture process zone development at the wood-adhesive interface (failure zone). An analytical formulation is then proposed allowing the evaluation of peak load of each specimen, which highlights a new approach for the design of such connections.

    Keywords

    Glued-in rodsMixed mode fractureEquivalent LEFMCrack closure techniqueR-curve

    References

    1. AFNOR (1999) Filetages mtriques ISO pour usages gnraux - Slection de dimensions pour la boulonnerie. NF ISO 262
    2. AFNOR (2005) Eurocode 5: Design of timber structures—Part 1–1 : General–Common rules and rules for buidings. EN 1995-1-1
    3. Bažant Z (1997) Scaling of quasibrittle fracture: hypotheses of invasive and lacunar fractility, their critique and Weibull connection. Int J Fract 83:41–65CrossRefGoogle Scholar
    4. Bažant Z (2002) Concrete fracture models: testing and practice. Eng Fract Mech 69:165–205CrossRefGoogle Scholar
    5. Bažant Z, Kazemi M (1990) Size effect in fracture of ceramic and its use to determine fracture energy and effective process zone. J Am Ceram Soc 73(7):1841–1853CrossRefGoogle Scholar
    6. Bengtsson C, Johansson CJ (2001) Girod–glued in rods for timber structures. In: Proceedings of the 34th conference of CIB-W18. International council for research and innovation in building and construction—timber structures, Venice, Italy. Paper 34-7-8
    7. Borri A, Corradi M (2011) Strengthening of timber beams with high strength steel cords. Compos Part B Eng 42:1480–1491CrossRefGoogle Scholar
    8. Broek D (1991) Elementary engineering fracture mechanics. Kluwer, DordrechtGoogle Scholar
    9. Broughton JG, Hutchinson AR (2001) Pull-out behavior of steel rods bonded into timber. Mater Struct 34(2):100–109CrossRefGoogle Scholar
    10. Buchanan AH, Moss PJ (1999) Design of epoxied steel rods in glulam timber. In: Walford GB, Gaunt DJ (eds) Proceedings of Pacific timber engineering conference. Rotorua, New ZealandGoogle Scholar
    11. Buchholz F, Grebner H, Dreyer K, Krome H (1988) 2D- and 3D-applications of the improved and generalized modified crack closure integral method. In: Computational mechanics ’88
    12. Caumes P (1987) Rupture d’un matériau anisotrope en conditions polymodales (le bois). Ph.D. thesis, Université de Bordeaux, France
    13. Coureau JL, Morel S, Dourado N (2013) Cohesive zone model and quasibrittle failure of wood: a new light on the adapted specimen geometries for fracture tests. Eng Fract Mech 109:328–340CrossRefGoogle Scholar
    14. De Moura MFSF, Oliveira J, Morais J, Xavier J (2010) Mixed-mode I/II wood fracture characterization using the mixed-mode bending test. Eng Fract Mech 77:144–152CrossRefGoogle Scholar
    15. Dourado N, Morel S, De Moura M, Valentin G, Morais J (2008) Comparison of fracture properties of two wood species through cohesive crack simulations. Compos Part A 39(2):415–427CrossRefGoogle Scholar
    16. Ferreira L, Bittencourt T, Sousa J, Gettu R (2002) R-curve behavior in notched beam tests of rocks. Eng Fract Mech 69:1845–1852CrossRefGoogle Scholar
    17. Fett T, Munz D, Geraghty R, White K (2000) Influence of specimen geometry and relative crack size on the R-curve. Eng Fract Mech 66:375–386CrossRefGoogle Scholar
    18. Franke B, Quenneville P (2014) Analysis of the fracture behavior of Radiata Pine timber and Laminated Veener Lumber. Eng Fract Mech 116:1–12CrossRefGoogle Scholar
    19. Fruhmann K, Reiterer A, Tschegg E, Stanzl-Tschegg S (2002) Fracture characteristics of wood under mode I, mode II and mode III loading. Philos mag A 82:3289–3298CrossRefGoogle Scholar
    20. Goland M, Reissner E (1944) The stresses in cemented joints. J Appl Mech 66(11):A17–A27Google Scholar
    21. Guitard D (1987) Mécanique du matériau bois et composites. Cépaduès
    22. Gustafsson PJ, Serrano E, Aicher S, Johansson CJ (2001) A strength design equation for glued-in rods. In: International RILEM symposium on joints in timber structures
    23. Hart-Smith LJ (1973) Adhesive-bonded single-lap joints. Tech. rep. Langley Research Center Hampton, Virginia
    24. Irabois (1999) Guide professionnel - Assemblages bois: tiges ou goujons collés de grande dimension, Les Cahiers, d’Irabois, vol 11, pp 1–29
    25. Irwin G (1958) Fracture I. Handb der Phys VI, pp 558–590
    26. Kossakowski P (2009) Mixed-mode I/II fracture toughness of pine wood. Arch Civ Eng 55(2):199–227Google Scholar
    27. Lartigau J (2013) Caractérisation du comportement des assemblages par goujons collés dans les structures bois. Ph.D. thesis, Université de Bordeaux
    28. Lartigau J, Coureau JL, Morel S, Galimard P, Maurin E (2012) Bonded-in rods connections: modeling of mechanical behavior. In: COST action FP1004
    29. Lawn B (1993) Fracture of brittle solids. Cambridge University Press, CambridgeCrossRefGoogle Scholar
    30. Lespine I (2007) Influence de la géométrie des structures sur les propriétés de rupture dans les milieux quasi-fragiles. Ph.D. thesis, Université de Bordeaux, France
    31. Mall S, Murphy J, Shottafer JE (1983) Criterion for mixed mode fracture in wood. J Eng Mech 109(3):680–690CrossRefGoogle Scholar
    32. Martín E, Estevéz J, Otero D (2013) Influence of geometric and mechanical parameters on stress states caused by threaded steel rods glued in wood. Eur J Wood Prod 71:259–266CrossRefGoogle Scholar
    33. Micelli F, Scialpi V, La Tegola A (2005) Flexural reinforcement of glulam timber beams and joints with carbon fiber-reinforced polymer rods. J Compos Constr 9(4):337–347CrossRefGoogle Scholar
    34. Morel S (2008) Size effect in quasibrittle fracture: derivation of the size effect law from equivalent LEFM and asymptotic analysis. Int J Fract 154:15–26CrossRefGoogle Scholar
    35. Morel S, Dourado N (2011) Size effect in quasibrittle failure: analytical model and numerical simulations using cohensive zone model. Int J Solid Struct 48:1403–1412CrossRefGoogle Scholar
    36. Morel S, Dourado N, Valentin G, Morais J (2005) Wood: a quasibrittle material. R-curve behavior and peak load evaluation. Int J Fract 131:385–400CrossRefGoogle Scholar
    37. Otero Chans D, Cimadevila JE, Gutiérrez EM (2008) Glued joints in hardwood timber. Int J Adhes Adhes 28(8):457–463CrossRefGoogle Scholar
    38. Qiu LP, Zhu EC, Van de Kuilen JWG (2014) Modeling crack propagation in wood by extended finite element method. Eur J Wood Prod 72:273–283CrossRefGoogle Scholar
    39. Raftery GM, Whelan C (2014) Low-grade glued laminated timber beams reinforced using improved arrangements of bonded-in GFRP rods. Constr Build Mater 52:209–220
    40. Riberholt H (1988) Glued bolts in glulam—proposals for CIB code. In: Proceedings of the 21st conference of CIB-W18. International council for research and innovation in building and construction—Timber structures, Parksville, Vancouver Island, Canada. Paper 21-7-2
    41. Rybicki E, Kanninen M (1977) A finite element calculation of stress intensity factors by a modified crack closure integral. Eng Fract Mech 9:931–938CrossRefGoogle Scholar
    42. Serrano E (2001) Glued in rods for timber structures: a 3D model and finite element parameter studies. Int J Adhes Adhes 21:115–127CrossRefGoogle Scholar
    43. Smith I, Landis E, Gong M (2003) Fracture and fatigue in wood. Wiley, New YorkGoogle Scholar
    44. Steiger R, Gehri E, Widmann R (2007) Pull-out strength of axially loaded steel rods bonded in glulam parallel to the grain. Mater Struct 40(1):69–78CrossRefGoogle Scholar
    45. Taupin JL (1980) Restauration à la résine époxyde de planchers et charpentes au monastère de la grande chartreuse. Bulletin d’informations tech 92:34–43
    46. Vasic S, Smith I (2002) Bridging crack model for fracture of spruce. Eng Fract Mech 69:745–760CrossRefGoogle Scholar
    47. 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 25:2881–2895Google Scholar
    48. Yoshihara H (2013) Initiation and propagation fracture toughness of solid wood under the mixed-mode I/II condition examined by mixed-mode bending test. Eng Fract Mech 104:1–15CrossRefGoogle Scholar

    For further details log on website :
    http://www.sciencedirect.com/science/article/pii/S0143749608000468

    No comments:

    Post a Comment

    Advantages and Disadvantages of Fasting for Runners

    Author BY   ANDREA CESPEDES  Food is fuel, especially for serious runners who need a lot of energy. It may seem counterintuiti...