3D-Modeling of Dowel-Type Timber Connections

Typical elements in structural engineering (beams, trusses, plates and shells) can be investigatedby means of quite simple material models employing a small number of material properties,especially as wooden structures are loaded within the elastic domain only and plasticity is nottaken into account. When investigating details, e.g. connections, three-dimensional stress andstrain distributions occur. At areas with local stress concentrations, elastic limit states maybe reached at low global load levels, but local plasticity need not endanger the stability of theentire structure. This study investigates dowel-type steel-to-timber connections. In particular, the behavior ofwood under high pressure loads and when yielding as well as the influences of contact and frictionbetween dowel and wood and of the nonlinearity of steel when yielding on the load carryingcapacity of the connection are analysed. The aim is to createa tool for reliable prediction ofthe strength and deformation characteristics of dowel-type timber connections. For this purpose, an elasto-plastic material model for woodwas developed and implemented intothe Finite Element programAbaqususing anUMAT-subroutine. A closed, single-surface Tsai-Wufailure criterion is used in combination with an associatedflow rule. The current model is ableto predict failure in wood (brittle and ductile behavior) locally as well as the different loadcarrying mechanisms (rigid dowel or plastic hinges in the dowel) on a global level. Additionally,a series of experiments is planned for validation.Ej belagd 160407