Nonlinear Material Models for Analysis of Bolted Wood Connections

Three-dimensional (3D) constitutive models for wood were developed and evaluated for use in a 3D numerical model of a bolted wood connection. The connection model applies to parallel-to-grain loading of wood. Nonlinear parallel-to-grain compression of wood and degradation of shear stiffness are described using a trilinear stress-strain relationship. Elastic parameters were determined that best fit numerically predicted load-displacement (P-Δ) curves to those obtained from experiments on bolted connections. The connection model also accounted for an elastic–perfectly plastic steel pin, oversized hole, and a changing contact surface at the pin-hole interface. The numerically obtained P-Δ curves were generally stiffer than the experimental curves but displayed important characteristics found in the experimentally obtained curves. Effects of material property assumptions and different forms of the trilinear curves were also evaluated.