Non-Linear Dynamic Analysis of Timber Frame Structure with Bolted-Fastener Connections

Understanding the dynamics of timber structures is essential for the timber structural engineering field, where it is necessary to build predictive numerical models and digital twins. Three similar-sized representative post-beam bracing frames with wood–metal assemblies were tested. Experimental modal analysis gave some indication of the non-linear behaviour of the structure. Then, the frame was submitted to a logarithmic sine sweep, which highlighted some specificities of the non-linear modes: dependence on the sweep direction and amplitude, jump, etc. These phenomena can be explained by friction and shocks in the assemblies. An accurate model of these non-linearities could lead to resilient and more earthquake-resistant timber structures, as the equivalent damping of a non-linear structure is way lower than for a linear one.