Speaker
Description
Interest in beam-lattice metamaterials is growing nowadays. They mimic classic crystalline lattices and exhibit promising properties, including low weight, enhanced flexibility, and efficient energy absorption. In the analysis of beam-lattice metamaterials, instabilities analogous to the classical Euler instability are often anticipated. For instance, in elastomeric open-cell foams, such instabilities manifest as a plateau in the microscale force-displacement response, which resembles plastic behaviour.
The objective of this lecture is to examine multistable structures, defined as systems possessing multiple equilibrium states under a specified external force. These structures are known to display intricate snap-through and snap-back phenomena. As a representative example, a periodic truss system constructed from elementary cells analogous to the von Mises truss will be analyzed. Equilibrium equations have been derived for select configurations, and the corresponding equilibrium paths are presented. Despite their nominal simplicity, these systems may exhibit complex mechanical responses, with equilibrium paths characterized by multiple loops and branches. Parametric analyses will also be discussed.
Finally, further modeling of these structures is undertaken utilizing effective medium approaches that account for material instabilities.