Predictions of compressive strength and kink band orientation for wood species

A modeling approach for the kink band formation in wood is developed in order to predict the compressive strength and the band inclination for some wood species (spruce and beech). The model accounts for the large fiber misalignment observed in wood and for its behavior in shear and in the direction transverse to the fibers. The behavior of wood under this last regime proves to play an important role in giving the kink band its orientation. For this purpose, wood behavior, which is size dependent, is experimentally examined at the kink band scale in order to properly determine all the needed material parameters for the model. Then, combined with a criterion well suited for the description of the anisotropic failure of wood and using the experimental measurements, the resulting formulation for the kink band mechanism gives estimations of both the compressive stress at kink formation and the band inclination, in very good accordance with experimental observations.