Finite strain analysis of wood species under compressive failure due to kinking

Finite element analysis of kink band formation in wood is carried out using an anisotropic failure criterion. The criterion is capable of describing the mixed mode I/mode II crack development observed in the kinked region. The evolution of cracking is simulated with the help of the so-called smeared crack approach. As for the finite rotation of the fibers in the kinked material, it is implemented in the finite element code through a hypo-elastic law characterized by an objective derivate using the rotation of the fibers. This formulation enables to follow strictly the matter under finite strain; which means that the evolution of the orthotropic directions is correctly described. Numerical results, such as the predicted load carrying capacity of wood under compression and its post-cracking behavior, prove to have a good agreement with the experimental observations. Further, the applicability of softening orthotropic plasticity under finite strain conditions for simulating compressive failure modes in wood is established.