Issue 31

C.L. dos Santos et alii, Frattura ed Integrità Strutturale, 31 (2015) 23-37; DOI: 10.3221/IGF-ESIS.31.03 36 account for brittle failure modes. However the EC5 procedures do not allow the prediction of the complete load- displacement behaviour of the joint. Numerical simulations were performed considering distinct alternative constitutive modelling strategies. The T-joint simulation assuming elastic-plastic behaviour for both wood members allowed for a non-linear description of joint behaviour, but the ultimate loads related to the collapse of the connection were not accurately described. The use of cohesive damage models enables the simulation of failure modes and respective collapse loads. However, the exclusive use of cohesive damage models with elastic materials provides load-displacement curves without ductility. The simultaneous use of plasticity models with cohesive damage models, allowed the reproduction of both ductility and connection collapse. In the simulated example, the assumption of an elastic behaviour with cohesive damage, for the side member, also revealed satisfactory results, if the central member is simulated as a plastic material. The initial crack in the side member exhibits a shape change, from corner to almost centre crack, when the elastic-plastic behaviour was imposed to this member. This crack configuration needs experimental validation. R EFERENCES [1] Itany, R.Y., Faherty, K.F., Structural wood research, state-of-the-art and research needs, ASCE, New York, (1984) 210. [2] Soltis, L.A., Wilkinson, T.L., Bolted-connection design, General technical report FPL-GTR-54, Forest Products Laboratory – USDA, Madison, WI, (1987). [3] EN1995-1-1 Design of timber structures. Part 1-1: General rules and rules for buildings, CEN, Brussels, (2004). [4] Johansen, K.W., Theory of timber connections, Int Assn Bridge Struct Eng Pub. 9, Zurich, Switzerland, (1949) 249– 311. [5] Patton-Mallory, M., Pellicane, P.J., Smith, F.W., Modelling bolted connections in wood: review, J Struct Eng, 123 (1997) 1054–62. [6] EN383: Timber structures. Test methods. Determination of embedding strength and foundation values for dowel- type fasteners, CEN, Brussels, (2007). [7] Sawata, K., Yasamura, M., Estimation of yield and ultimate strengths of bolted timber joints by nonlinear analysis and yield theory, J Wood Sci, 49 (2003) 83–91. [8] Chen, C.J., Lee, T.L., Jeng, D.S., Finite element modelling for the mechanical behaviour of dowel-type timber joints, Comput Struct, 81 (2003) 2731–2739. [9] Racher, P., Bocquet, J.F., Non-linear analysis of dowelled timber connections: a new approach for embedding modelling, Electron J Struct Eng, 5 (2005) 1–9. [10] Kharouf, N., McClure, G., Smith, I., Elasto-plastic modelling of wood bolted connections, Comput Struct, 81 (2003) 747–54. [11] Moses, D.M., Prion, H.G.L., A Three-Dimensional Model for Bolted Connections in Wood”, Can J Civil Eng, 30 (2003) 555-567. [12] Moses, D.M., Prion, H.G.L., Stress and Failure Analysis of Wood Composites: A New Model, Compos Part B-Eng, 35 (2004) 251-261. [13] Moses, D.M., Prion, H.G.L., Anisotropic Plasticity and the Notched Wood Shear Block, Forest Prod J, 52 (2002) 43- 54. [14] Patton-Mallory, M., Cramer, S.M., Smith, F.W., Pellicane, P.J., Nonlinear Material Models for Analysis of Bolted Wood Connections, J Struct Eng, 123 (1997) 1063-1070. [15] Yasumura, M., Daudeville, L., Fracture of Multiply-Bolted Joints Under Lateral Force Perpendicular to Wood Grain, J Wood Sci, 46 (2000) 187-192. [16] Ballerini, M., Rizzi, M., 2007, Numerical analyses for the prediction of the splitting strength of beams load perpendicular-to-grain by dowel-type connections, Mater Struct, 40(1) (2007) 139–149. [17] Daudeville, L., Yasumura, M., Failure Analysis of Timber Bolted Joints by Fracture Mechanics, Mater Struct, 29 (1996) 418-425. [18] EN26891-Timber structures – Joints made with mechanical fasteners – General principles for the determination of strength and deformation characteristics, (1991). [19] Swanson Analysis Systems Inc., ANSYS ® Version 12.0, Houston, (2009). [20] Resch, E.. Kaliske, M., Three-dimensional numerical analyses of load-bearing behavior and failure of multiple double- shear dowel-type connections in timber engineering, Comput Struct, 88 (2012), 165-177.