Crack path tracking using DIC and XFEM modelling of mixed-mode fracture in wood

Abstract

Abstract A wedge split test in mode I and mixed-mode was designed and performed for wood at structural component scale. The displacement fields around cracks during propagation were recorded and analysed to provide information on crack tip position, the composition of deformation modes, resistance to fracture propagation, and separation of the crack lips. The data were fed into a non-linear numerical finite element model. A cohesive zone model based on the eXtended Finite Element Method was applied for mixed-mode fracture in 2D rectilinear orthotropic materials. Extrinsic exponential traction-separation laws for modelling mixed-mode splitting of wood from Norway spruce along the grain were calibrated to experimental crack data. The chosen model captures well the damage initiation and crack propagation in wood along the grain. The simulation results show the importance of initial crack length and actual mode composition as model parameters.