NEW SPLITTING METHOD FOR WOOD FRACTURE CHARACTERIZATION

A testing procedure with a new and simple specimen shape is presented which is appropriate to characterize fracturing of inhomogeneous and c omplex materials like wood. With this, the fracture energy of spruce w ood is determined in the TL and RL direction. The ''size effect'', i.e . influences of specimen dimensions on K-IC and G(f) (specific fractur e energy) are investigated. Stress and deformation distribution in the newly developed specimens are analysed with FE methods. The measured load-displacement curves are approximated by bilinear softening diagra ms and FE analysis. Based on these results, it is tried to interpret t ypical deviations from LEFM's behaviour by mechanisms like microcracki ng, crack branching or crack tip bridging.