A topology optimization approach applied to metamaterial mechanism design

Cícero R. de Lima¹; Glaucio H. Paulino²

¹ UFABC - Federal University of ABC; ² Georgia Tech

doi:10.20906/CPS/CILAMCE2017-0048

Resumo

Metamaterials are artificial structures that perform unconventional mechanical properties. These structures are obtained by a repetitive cell patterns, rather than the material they are made of. Each cell of the metamaterial can be designed to have a controlled directional movement. This allows to create devices with a desired mechanical function, such as the mechanisms. In this work, compliant mechanism is designed by using the Topology Optimization (TO) method to generate microstructure unit cells that simulate the effect of metamaterials that have negative Poisson's ration (auxetic materials). The unit cell (microstructure) of metamaterial is driven to have the same characteristics of a compliant mechanism, that is, a monolithic body that delivers a desired motion when is loaded in a certain way. Thus, the topology optimization problem of compliant mechanisms is proposed to design more efficient these microstructures for a certain specific structural mechanical property, such as the auxetic behavior. Polygonal finite element meshes are introduced in the TO formulation to avoid the hinges (one-node connections) in the compliant mechanism design. Moreover, a pattern repetition constraint is applied to generate an auxetic macrostructure, allowing to create a metamaterial mechanism efficiently. Computational simulations are also carried out to verify the results of the metamaterial design.

Palavras-chave: topology optimization; compliant mechanism; auxetic structure; polygonal elements