Fracture characterization of wood under Mode I loading using the SEN-TPB Test

Abstract

Mode I fracture characterization was induced in wood (Picea abies L.) using the single-edge-notched beam loaded in three-point-bending. A developed data reduction scheme based on the equivalent linear elastic fracture mechanics was used to evaluate the Resistance-curve instead of classical methods. The method is found on beam theory and crack equivalent concept taking into account the triangular stress relief region that develops in the crack vicinity. The method dispenses crack length monitoring in the course of the loading process, providing a complete Resistance-curve which is essential for a clear identification of the fracture energy. The validation of the procedure has been performed numerically using a bilinear cohesive damage model, thus allowing the simulation of both damage initiation and growth. The numerical model also provided the critical specimen dimensions that permit the attainment of accurate evaluation of the fracture toughness in wood.