A model for the through-thickness elastic-plastic behaviour of paper (Q1434696)

The model presented in this paper is a model for combined shear and normal out-of-plane loadings. The elastic-plastic model is developed for quasi-stable conditions and constant climate. The change of material behaviour due to changes in deformation rate and moisture content is handled elsewhere. The model is based on the idea of a bounding surface that grows in size with plastic compression. Here, both the bounding and the yield surfaces are suggested as parabolas in stress space. The parabolic yield surface is in through-thickness compression bordered by the maximum applied through-thickness compression.