EFFECT OF MOISTURE CONTENT ON MODE I AND MODE II FRACTURE TOUGHNESS OF WALNUT AND CHERRY

摘要

The mode I and mode II fracture toughness of walnut and cherry wood were determined my means of Arcan tests. Two specimen types (RT and TR systems) were prepared for both species and and acclimatised to conditions of 50, 65 and 85% relative humidity and a con-stant temperature of 20°C. The results indicated that fracture toughness was not related to moisture content, which is not in agreement with previous studies. In mode II test, a crack propagated in the direction normal to the shear plane, and not parallel to it. Hence, we conclude that it is difficult to determine the fracture toughness of RT or TR hardwood specimens in mode II.