Morphological lattice models for the simulation of softwood failure and fracture

Abstract

AbstractThis paper details the development of morphological lattice models to simulate fracture and failure in softwood. The lattice models rationally incorporate growth-ring geometry, differences in strength and stiffness between earlywood and latewood, and variations observed in the grain direction of clear wood (grain perturbation). Details regarding the implementation of these features are presented. Grain perturbation is shown to be a significant contributor to strength and stiffness variability. Simulations demonstrate that the inclusion of growth-ring geometry and incorporation of differences in the mechanical properties of earlywood and latewood are necessary for the lattice models to predict realistic fracture paths. Results are presented for laboratory tests on small red spruce specimens loaded in parallel-to-grain tension and shear. The lattice models give good predictions of mean specimen stiffness and strength, and reasonable predictions of strength variability. The fracture paths predicted by the lattice models are in excellent agreement with the experimental observations.