DETERMINATION OF MODE I FRACTURE BEHAVIOR OF SOUTHERN YELLOW PINE (PINUS TAEDA L.) WOOD USING SINGLE-EDGE-NOTCHED BENDING TEST

The fracture behavior of southern yellow pine (Pinus taeda L.) was experimentally analyzed in the radial-longitudinal and the radial-tangential crack propagation systems using asingle-edge-notched bending test method in mode I loading condition. Three fracture parameters, the initial slope, the fracture toughness, and the specific fracture energy, were determined from the obtained load-deformation curves of each test sample. The results were statistically analyzed and compared with each other using the independent samples t-test. Theradial-longitudinal crack propagation system had a significantly greater fracture toughness than in the radial-tangential crack propagation system. The stiffness in the radial-longitudinal system was also significantly higher than in the radial-tangential system. It was observed that the crack growing in the tangential direction needed more energy per unit area to separate awood sample into two halves. However, there was no significant difference between thespecific fracture energy values of crack propagationsystems.