Abstract

Previously developed 3D Connector-Beam Lattice Model for Wood (CBL-W) has proved its capability in predicting crack initiation and growth in wood mesoscale cellular structures. Now the CBL -W model has been utilized to investigate the growth-ring orientation effects observed in the compact tension tests of eastern spruce. The numerical investigation involved specimens with a 5-mm precrack loaded at three different end-grain orientations relative to initial crack directions: 0, 45, and 90 degrees. Results showed that cracks followed a straight radial path, due to the earlywood and latewood cell wall tearing, dominant at 0 degree, produced higher energy release than cell wall separation through the earlywood and latewood boundaries before settling once again in an earlywood region, which dominates in 45 and 90 degrees crack propagation. Partial fracture deflection and meandering have been identified as one of the most dominant mechanisms for toughening, observed in the post-peak stages of crack growth.