Numerical study on structural-scale wood scrimber beams: modelling, calibration, and size effect

Wood scrimber is an innovative wood product that offers a viable solution to the shortage of large-sized wood required for structural applications. This study provides comprehensive methodologies for the numerical modelling of structural-scale beams made of scrimber. Initially, a constitutive law was developed for this product, integrated into ABAQUS/Explicit as a user-defined subroutine (VUMAT). It was found that the explicit subroutine could accurately capture failure modes, avoid convergence problems, and eliminate the need for specifying mesh-size dependent fracture energy. Subsequently, a calibration approach was proposed for the non-standard specimens to transform material parameters from experimental data to simulation data, addressing the errors between macroscopic specimens and microscopic elements caused by buckling and uneven stress distribution. Furthermore, to model the bending behaviour of a structural-scale scrimber beam, a strategy was proposed to account for the size effect, wherein the compressive strength was reduced according to a specific formula, while the tensile strength was assumed to remain unchanged. The results demonstrate that the size effect resulted in an 8.4% reduction in load capacity. The numerical result accounting for the size effect significantly improved agreement with the test data, reducing the maximum error in bending stiffness from 14.6–1.2%.