3D orthotropic damage model for the failure analysis of LVL wood truss with steel connector through a regularized extended finite element method

Any three-dimensional finite element analysis of the failure of wood trusses necessarily incurs several markedly nonlinear effects, including the co-existence of orthotropic ductile and brittle failure modes depending on entangled tensile, shearing, and compressive stress states, and the mesh dependency inherent in the adoption of softening stress state laws. The complexity of the modelling process is even more severe in the presence of steel connectors. Furthermore, the experimental evidence shows that the failure modes and patterns often vary in a significant way even for the same specimen geometry and in the presence of highly engineered timber because of the persistence of defects and heterogeneities. Therefore, ad hoc computational models should be able to capture this peculiar variability of failure configurations. All these issues are properly tackled by the present nonlinear finite element procedure. The adoption of a regularized extension of the extended finite element method, indeed, allows for transitioning from the continuous interpolation of the displacement field within an orthotropic elastic-damaging material to a regularized discontinuous kinematic description based on a length-enriched extended finite element method. The present formulation is successfully validated by simulating experimental data concerning a set of failure tests on Laminated Veneer Lumber trusses with pulled steel connector.