Kink band formation in wood species under compressive loading

The design of wood structures, such as columns and beams, requires the knowledge of the compressive behavior of wood. Several wood species, hardwoods and softwoods, are tested under compression parallel to grain to investigate experimentally the formation of kink bands and the relationship between this localized mode of failure and wood anatomy. In order to determine the correct test method for successful observation of kink banding, an experimental plan is first carried out. Then, several characteristics of kink bands, as well as the compressive behavior of the specimens, are comparatively analyzed for the various wood species. Based on these observations and some theoretical predictions corroborated by experimental data, it is shown that compressive kinking strength of wood is governed mainly by its yield strength in shear and by certain features of its anatomy related to the so-called ray cells.