A constitutive numerical modelling of hybrid-based timber beams with partial composite action

The flexural behaviour of hybrid timber beams is very complex because of the combination of the two different material behaviours and their nonlinar and partial compostion action. Numerical simulation of such behaviour requires an accurate description of the nonlinear material behaviour, in particular that of timber because of its anisotropic nature. A realistic description of the material nonlinearities and of the composite action between the different materials could aid considerably in achieving acceptable predictions. An incremental approach based on the strong coupling between orthotropic elasticity, anisotropic plasticity with mixed nonlinear isotropic hardening and an isotropic damage is used. The developed constitutive model for timber is implemented in Abaqus code using an external subroutine. The 3D FE model is calibrated and validated through comparison with experimental data reported in literature. The model is able to predict the nonlinear structural response of hybrid beams in terms of load-midspan deflection, and provides an acceptable accuracy.