A nonlocal continuum damage model for timber: Development, implementation, and application

The phenomenological constitutive modelling of timber requires complex anisotropic failure criteria or a combination of failure surfaces that adequately capture different failure modes ranging from brittle to ductile. Additionally, localization of strain/damage (associated with softening of the material) adds another layer of complexity to constitutive modelling of timber by rendering finite element (FE) simulations sensitive to size and orientation of the FE mesh. A generic three-dimensional (3D) nonlocal integral continuum damage constitutive law was developed for timber. The proposed model took advantage of symmetric attenuation function that consistently treats transition from local to nonlocal state while alleviating the boundary effects in the finite support domains. The developed nonlocal constitutive law was implemented in ABAQUS for FE simulation of timber. Values for interaction radius of the nonlocal model are proposed, and the model was verified against a wide range of experimental data. It is shown that the proposed nonlocal FE model captures load-carrying capacity and different failure modes of timber and effectively restores the objectivity of the results, whereas the FE model without strong localization limiters considerably underestimates the load-carrying capacity.

Automated summary

The phenomenological constitutive modelling of timber involves capturing different failure modes and strain/damage localization. A nonlocal integral continuum damage constitutive law was developed for timber and implemented in ABAQUS for finite element simulation. The model captures load-carrying capacity and different failure modes effectively and restores the objectivity of the results.