Discussion of: “Mode II fracture mechanics properties of wood measured by the asymmetric four-point bending test using a single-edge-notched specimen of Hiroshi Yoshihara Eng. Frac. Mech. 75 (2008) 4727–4739”

A discussion is given of the article mentioned in the title. The conclusions of this article, based on classical fracture mechanics, are shown to be questionable in the light of new theory and the there preferred mode II asymmetric four point bending test is shown to be problematic in giving the right values of fracture toughness and release rate. The in the article given data provide information on equivalent mode II softening behaviour and confirms that the strength of the intact fracture plane then is determining, the same as applies for mode I.

► Based on new theory, the classical fracture mechanics approach is discussed.
► The disadvantage of the asymmetric four point bending test is discussed.
► The basis of Mode II behaviour of the single edge-notched beam test is discussed.