Shear and crack tip deformation correction for the double cantilever beam and three-point end-notched flexure specimens for mode I and mode II fracture toughness measurement of wood

Using specimens of western hemlock with various depths, double cantilever beam and three-point bend end-notched flexure tests were conducted to obtain the mode I and mode II fracture toughness. To correct the deflection caused by shearing and crack tip deformation, four conventional data reduction methods were examined as well as the compliance combination method, which was proposed by the author. In addition to the actual fracture tests, finite element analyses were conducted and the validity of the data reduction methods were also examined. The compliance combination method was more suitable for the data reduction than the others examined here because the fracture toughness was determined simply and appropriately while correcting the deflection caused by shearing as well as the crack tip deformation. (C) 2008 Elsevier Ltd. All rights reserved.