Fracture toughness of wet and dry Pinus radiata

Pinus radiata

were determined using a three-point bend test and a compact-shear specimen test respectively. The fracture toughness across the grain (LT and LR) in mode 1 was ten times greater than in other directions for both wet and dry specimens. The mode 1 fracture toughness of wet wood was lower than dry wood in every orientation except TR. The mode 2 fracture toughness for dry wood was found for all directions except the longitudinal ones (LT and LR). In the longitudinal direction, mode 2 fracture did not occur, as the wood failed in compression before its shear limits were reached. In wet wood, pure mode 2 fracture occurred only in the RL direction. In other directions, the fracture did not originate from the notch tip, or the wood fractured in a mixed mode.