Numerical Investigation of the Fracture Pattern in Cedar Wood by Finite Element Method by Considering Grain Direction

The transverse strength of wood is influenced by numerous naturally inherited factors such as grain direction, proportion of latewood and earlywood and microstructural arrangement. The mechanisms of transverse fracture in such material is thus a function of the combined effect of the aforementioned structural features. The aim of this study is to explore the influence of structural features, namely grain direction and variation in orthotropic properties on the transverse fracture of Japanese cedar (Cryptomeria japonica) by considering 3point bending investigation in finite element method (FEM). To this end, three types of Japanese cedar specimen with varying grain distribution, namely longitudinal-radial (LR), longitudinal-tangential (LT) and radial-longitudinal (RL) were considered. The selected specimens were modelled on finite element modelling and post processing software (FEMAP) and simulation was conducted on LS-DYNA. In comparison to LR and RL specimens, FEM results revealed a unique transition in fracture pattern of LT specimens with varying material properties. From results of this study, it has been deduced that the unrestricted mechanisms of crack propagation observed in natural materials like Japanese cedar predominantly occurred as a result of inferior transverse strength. Lessons learned about the transverse fracture in natural materials are beneficial when crafting advanced composite materials with enhanced ability to resist transverse fracture.