An Analysis of Rolling Shear of Spruce Wood by the Iosipescu Method

Abstract

Summary Shearing is an essential deformation in the treatment of mechanical pulp fibers into a papermaking pulp. Knowledge of the contribution of shear to the fiber treatment during processing can be obtained by measurements on fibers in the form of wood. In this work, an attempt was made to use the Iosipescu method for testing wood in rolling shear. Despite the small size of the shear region of interest between notches made in the wood, the results and their dispersion in both the elastic and inelastic ranges were in accordance with previous results found using other testing methods. The stress-strain relationship was analysed in relation to the specimen's density profiles in the region of interest. Differences in density explained up to 50% of the inter-specimen variability in the shear modulus and in the inelastic behavior. Failure occurred outside the shearing zone in a large number of specimens. Thus the configuration chosen was not adapted to provide for the strength of wood in rolling shear. This behavior limited the amplitude of the strain that could be reached between the notches.