Elasto-plastic and bifurcation response of chiral, anti-chiral and hierarchical periodic structures
Babak Haghpanah (Northeastern University), Davood Mousanezhad (), Ashkan Vaziri ()
Mechanics and Dynamics of Periodic Structures
Wed 1:30 - 2:50
Salomon 101
Chiral, anti-chiral and hierarchical periodic patterns are crucial to understanding and emulating many living and non-living structural systems at different scales, including molecules, enzymes, and the microstructure of nacre. Studying the mechanical behavior of these structures, however, relatively new and could have a significant impact on the design of meta-materials and multifunctional structural systems. In this study, analytical approaches for obtaining the bifurcation response of 2D (honeycombs) and 3D (foam) tessellated structures are introduced. The methods lead to closed-form relations for the post-buckling response of the tessellated pattern under a general state of stress, and is applied to a representative volume element (RVE) of the structure. In addition, a comprehensive analytical, numerical and experimental study on the elasto-plastic response of a series of novel periodic structures including hierarchical, chiral and anti-chiral honeycomb structures with triangular, square and hexagonal unit cells are performed. The elastic properties of the cellular lattices are obtained through the energy method, and the plastic collapse strength of the structures is determined through the upper-bound collapse limit, allowing closed-form expressions for the elastic-plastic behavior of the structures. The findings from the analytical expressions are confirmed by the finite element analysis.