Structural Metamaterials: CANCELLED - Session IV
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division, TMS: Additive Manufacturing Committee, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Amy Wat, Lawrence Livermore National Laboratory; Brad Boyce, Sandia National Laboratories; Xiaoyu Zheng, University of California, Los Angeles; Fabrizio Scarpa, University of Bristol; Robert Ritchie, University of California, Berkeley
Tuesday 4:00 PM
March 1, 2022
Room: 304A
Location: Anaheim Convention Center
4:00 PM Cancelled
Multi-phase Viscoelastic Kirigami Plates: Shahram Janbaz1; Corentin Coulais1; 1Universiteit van Amsterdam
Kirigami has been proven as a practical outline to fabricate flexible mechanical metamaterials with complex patterns of instability. In the absence of a well-controlled activation scheme, kirigami metamaterials may deform randomly into various 3D shapes while stretched. Here, we show viscoelasticity can effectively control the direction and the modes of buckling in such flat materials. Our approach enables reliable switching between various modes in response to the applied strain-rate. Our experimental study confirms the practicality of producing such “viscoelastic kirigami plates” using conventional additive manufacturing techniques. Furthermore, we show that phase-transformation via relaxation can be harnessed to conduct mechanical waves and dynamic pattern evolution in pre-stretched kirigami plates. Additionally, we developed a 1D dimensionless model that explains the requirement of soliton waves in the continuum limit. Our approach serves as a basis for designing metamaterials with well-controlled and dynamic functionalities that inherit their properties from their viscoelastic kirigami backbone.
4:20 PM Cancelled
CANCELLED: Sequential Deformation in Metamaterials Tuned by Elastoplastic Buckling: Wenfeng Liu1; Shahram Janbaz1; Corentin Coulais1; 1University of Amsterdam
Buckling, a common instability behavior, is usually used in mechanical metamaterials. So far, buckling in metamaterials is mostly considered in elastic systems, which only depends on the geometry. Compared to elastic buckling, elastoplastic buckling not only depends on the geometry, but the material properties, which allows one geometry pattern to have different buckling sequences. To apply the elastopalstic buckling into metamaterials, here, we developed a new class of metamaterials with line modes where we can achieve two different buckling sequences of line modes by material properties. Such metamaterials become hard to control in large elastic systems where the line modes are easy to bifurcate to global rotating mode. While elastoplastic buckling could separate the line modes from global buckling mode and achieve sequential multi-stable and multi-step deformations. Our work established a general pathway to tune the sequential deformation in metamaterials with elastoplastic buckling, which could be useful in energy absorption.