P_2.2.2 mech_mod

Material Model Timber – Development of a General Material Model for Strength and Deformation Calculations of Timber Constructions and Construction Details

Existing material models are relatively well suited for deformation calculation of timber constructions or details. However, the practical possibilities of use for strength calculations are currently insufficient.

The objective here is the development of a macroscopic and practically speaking relatively easy-to-use general material module concerning timber as applied for FE analyses. The material serves to calculate any deformations as well as the supporting capacities of structures. The calculation of local details together with an explanation of effects specific to timber engineering regarding selected constructions, such as glulam bending beams, cross laminated timber plates or wall disks subject to shear strain with or without apertures or gaps and the application of the same in typical problem situations is also envisaged. Timber engineering related questions that have so far not been answered shall be examined in-depth in this way with a view to increasing understanding and bringing about improvements while also significantly reduce any possible failure of such timber structures.

At the basis of this project is the existing implementation of a 3D material model for timber as a USER subroutine for the ABAQUS FE package. This material model works on the assumption of a linear elastic orthotropic material behaviour until the desired firmness is reached. Once this degree of firmness is exceeded, either a linear or non-linear hardening take place depending on the tension component under pressure in or transversal to the grain direction; or an exponential softening parallel to the grain direction take place for tension and shear tensions. So far, interactions between the individual tensions are not envisaged.