An orthotropic multi-surface elastic-damaging-plastic model with regularized xfem interfaces for wood structures

Wood is an extraordinary natural composite material exhibiting a pronounced orthotropic behaviour, and markedly different properties along the parallel and transverse-to-the grain directions. It displays a strongly non-linear response, almost elastic-plastic under compression and elastic-damaging under tension and shear. Restoration and development of smart wooden based elements are gaining an increasing interest in the building industry. In this context, the computational challenge is to develop numerical constitutive models that account for the complex, strongly non-linear, nature of wood behaviour. In the present contribution, we develop a novel constitutive model obtained by coupling a non-smooth multi-surface plasticity model for compressive failure modes, with an orthotropic damage model for ten-sile/shear failure modes. Joints are modelled with a regularized version of the eXtended Finite Element Method (XFEM) that allows to model the development of the crack process zone, while ensuring mesh-size independent results and a smooth continuous-discontinuous transition. It is shown that the obtained numerical results satisfactorily fit with experimental data.