A numerical study on the SEN-TPB test applied to mode I wood fracture characterization

A numerical study involving the single edge notched-three point bending test was methodically performed to evaluate its adequacy for wood fracture characterization under mode I loading. Stress analysis along the ligament length using cohesive zone modeling allowed understating the influence of the compressive stresses induced by bending on the stress profile for geometrically similar specimens with different sizes. The stress relief region induced by the presence of the crack was identified by a stress analysis procedure along the beam length. A data reduction scheme based on the beam theory and on the crack equivalent concept was then developed considering an approach using a rectangular stress relief region. The method allows estimating the Resistance-curve without monitoring the crack length during propagation. Important remarks regarding the aspects which contribute to explain the size effect phenomenon in wood are highlighted in this study. Following the presented procedure the application of the single edge notched-three point bending test for wood fracture characterization under mode I has become considerably user-friendlier.