Design of mechanical metamaterials with strain coupling effects by lattice symmetry and micropolar elasticity

Date: 2022/08/06 - 2022/08/06

Dissertation Title: Design of mechanical metamaterials with strain coupling effects by lattice symmetry and micropolar elasticity

Speaker: Zhiming Cui, Ph.D. candidate at UM-SJTU Joint Institute

Time: 10:00 a.m., August 6th, 2022 ( Beijing Time)

Location: via feishu

Abstract

Rationally designed materials have many unusual properties that do not exist in nature; one of which recently drew much attention is the mechanical coupling effect, including compression-induced twist, compression-induced rotation, and compression-induced shear. However, these coupling effects have been discovered on an ad hoc basis; there is no systematic investigation to explore the coupling effects integrated with constitutive equations in the material design. By combining the point group theory of crystallography and the micropolar elasticity, the author identifies eight mechanical coupling effects in the planar lattices and provides a guideline to obtain coupling effects by designing the symmetry of the lattice. The author demonstrates compression-induced shear with chiral square lattice, compression-induced bending with non-centrosymmetric square lattice, and other coupling effects using the finite element method based on the design principle of the theoretical model. Furthermore, the author extends the theory to three-dimensional lattices, exploring more possibilities of mechanical coupling effects. The systematic explanation of coupling effects provides a deeper understanding of mechanical metamaterials, increases the design space of lattice materials, and accelerates the application of coupling effects in actuators, sensors, and functional metamaterials.

Biography

Zhiming Cui received his B.S. degree of Mechanical Engineering from Zhengzhou University in 2017. He is currently a Ph.D. student at UM-SJTU Joint Institute, Shanghai Jiao Tong University. His research interests are metamaterials with mechanical coupling effects.