Simulation and analysis of adhesive failure in Glued-in Rod (GiR) connections for timber structures

Paper in proceeding, 2019

Adhesive joints have been known and used in different applications within the area of structural and mechanical engineering for decades. Hybrid joints with glued-in rods are nowadays increasingly used as an efficient way for both constructing new and strengthening/repair of existing timber structures. However, despite ongoing research since the 1980s, general and reliable design criteria for such connections are missing in the European standard for timber structures, Eurocode 5, and there is contradiction between the load bearing capacity predicted by different existing design models. In this study, the adhesive bond-layer failure, as the dominant failure mode in GiR connections, is simulated for single- steel rod joints based on the nonlinear elastic fracture mechanics (NLEFM) approach using Abaqus software. A finite element (FE) model, describing timber-adhesive interface failure, was established, calibrated as well as verified through comparison with existing test results reported in literature. The simulations are conducted for two different types of adhesives namely epoxy (EPX) and polyurethane (PUR). The single- GiR joints are loaded in axial tension and progressive failure is simulated to accurately predict the maximum load bearing capacity of the joints due the pull-out failure, in the timber-to-rod adhesive bond layer. A parameter study was conducted and the influence of some geometrical dimensions and material property parameters on the pull-out capacity of single-rod connections is investigated. It was shown that simplified axisymmetric models can also accurately describe the behaviour of single GiR connections when compared with a more realistic 3-D model, with significantly less processing time and computational effort.