Glued-in rods for timber structures — a 3D model and finite element parameter studies

A nonlinear 3D finite element model and a theoretical parameter study in relation to glued-in rods for timber structures are presented. A strain-softening crack band model was used to characterise the behaviour of the adhesive layer between the rod and the wood. The model is general in the sense that it bridges the gap between the theory of an ideal plastic bondline and the theory of linear elastic fracture mechanics. Two parameter studies were made. One in relation to fracture energy and geometrical parameters and the second in relation to loading conditions. The results show that the fracture energy is of major importance for the pull-out load capacity, that the present model can be used to predict such phenomenon like the size effect and that the loading in pull–compression results in lower load-bearing capacities than the loading in pull–pull.