The fracture mechanism of softwood via hierarchical modelling analysis

Abstract

A hierarchical model of softwood was developed to effectively analyze stress concentration and predict initial fracture of the wood cell wall under different loading scenarios. The results indicated that the simulated stress concentration regions of the tracheid wall approximately matched the experimental initial fracture locations. The stress concentration and initial fracture of the tracheid wall under longitudinal tensile stress occurred in the S 2 layer. In the cases of pure longitudinal-radial (LR) or longitudinal-tangential (LT) in-plane shear loading, the highest stresses are observed in the S 1 /S 2 interface and the S 3 layer, but the initial fractures of the tracheids of the neutral layer under the LR or LT shear stress only occurred in the S 1 /S 2 interface. Furthermore, the tracheids of the tensile parts outermost of bending specimen were subjected to the longitudinal tension and shear coupling stresses that led to the two kinds of cracks occurring, including trumpet-shaped cracks in the S 2 layer, and S 1 /S 2 interface debonding.

Computer modelling as a basis for forestry and wood processing equipment design

“…The authors Dong Wang and Lanjing Lin in their work [2] create a coniferous wood model for efficient stress concentration analysis and initial failure prediction. The ABAQUS software package was used for the modelling.…”

Numerical simulation of transverse compression and densification of wood

“…In this model, the microfibril angle of the S3 layer was set at −50°, and those of the S2 and S1 layers were, respectively, 10° and 70°. Finally, the fibre directions of P and M layers were set at 0° (Wang et al 2019).…”

“…However, the simulated compression process was limited to elastic and small deformations only. Wang et al (2019) established a FE model of a wood microstructure comprising twelve cells to study the relationship between the different cell wall layers and the fracture of the material under tension and shear loading. They analysed the stress concentrations and compared the crack position of a cell wall, as observed with a microscope.…”

Numerical Simulation of the Deformation Behavior of Softwood Tracheids for the Calculation of the Mechanical Properties of Wood–Polymer Composites

“…The simulated regions of stress concentration of the tracheid wall matched the measured initial fracture locations well. The initial fracture position of the cell occurs under in-plane shear loading at the S1-S2 interface and under longitudinal tensile stress at the edges of the S2 layer [28]. De Magistris et al presented an ABAQUS FEM model for simulating the deformation of wet wood under transverse compression and combined transverse shear and compression to analyze the mechanical pulping of wood chips in refiners.…”