5553 - NON-LINEAR FRACTURE MECHANICS APPLIED TO WOOD IN MODE I

The study presented in this document aims at using non-linear fracture mechanics in order to study the propagation of a longitudinal crack in wood in mode I. Finite-elements simulation are proposed to model crack. They are based on the using of joint-elements located on the crack path. The possibility to implement a constitutive damage law is investigated. Different shape and size of the local damage law are tested. Numerical results show that the local behaviour of the failure interface has an important influence on the Force-COD of DCB specimen. The peak load of the specimen is strongly dependent of the constitutive law form and the propagation of the crack can be expressed by the critical energy released rate defined in the frame of the Linear Elastic Fracture Mechanics. R-curves are determined from NLFM in order to study the influence of the constitutive damage law parameters on their shape. Study shows that new simulations should be performed; they would take into account a damaged volume by considering a non zero thickness failure interface.