Determination of mode I and mode II fracture toughness of walnut and cherry in TR and RT crack propagation system by the Arcan test.

Two specimen types, each from walnut and
cherry wood, were prepared for tangential-radial (TR) and
radial-tangential (RT) crack propagation systems at 65%
of RH and 20°C before mode I and mode II fracture toughness
was determined through Arcan tests. It was found
that fracture toughness in mode I is in agreement with
literature data. In the mode II test, however, the crack
propagated in the direction normal to the shear plane and
not parallel to it. The release rate of strain energy in terms
of the opening failure in mode II was lower than that in
mode I. It can be concluded that it is difficult to determine
the fracture toughness of RT or TR propagation in hardwood
specimens in mode II.
Keywords: Arcan test, cherry, fracture toughness, walnut