S3E6
Episode 6 (February 21, 2021)
Yunlan Zhang
University of Oxford
Huijuan Feng
Northumbria university
Multiaxial Behavior of Phase Transforming Cellular Materials
Abstract of Talk 2
Phase Transforming Cellular Materials (PXCMs) are periodic cellular materials whose unit cells exhibit multiple stable or meta-stable configurations. Transitions between the various (meta-) stable configurations at the unit cell level enable these materials to exhibit reusable energy dissipation. This energy dissipation arises from the storage and non-equilibrium release of strain energy accompanying the limit point traversals underlying these transitions. The material deformation is fully recoverable, and thus the material can be reused to absorb and dissipate energy multiple times. Here, two designs for functionally two-dimensional PXCMs, the S-type with four axes of symmetry based on a square motif and the T-type with six axes of symmetry based on a triangular motif, are presented. Experiments and simulations are employed to understand the various mechanisms that are triggered under multiaxial loading conditions. Both numerical and experimental results indicate that these materials exhibit similar energy dissipation for loads applied along the various axes of symmetry of the material.
Biosketch of Speaker 2
Dr. Yunlan Zhang is a Postdoctoral Researcher in the Department of Engineering Science, University of Oxford, Oxford, UK. She received her PhD and MS degrees in civil engineering from Purdue University in West Lafayette, Indiana, USA, and her BS in civil engineering from The Ohio State University in Columbus, Ohio, USA. After graduating with her PhD, she worked as a research engineer at Purdue University. Her research interests include architected materials, smart materials, deployable structures, and bioinspired materials. She combines her knowledge of materials and structures to create novel structures that vary from deployable medical devices to resilient infrastructure. She enjoys working with students just as much as conducting research.
Origami-based Morphing Structures and Metamaterials
Abstract of Talk 3
This talk will cover origami-based morphing structures and metamaterials, mainly focus on their design, modeling, fabrication and potential applications. Firstly, a new type of chiral unit for constructing homogeneous and heterogeneous chiral structures is proposed based on the origami technique. Helical structures with switchable and hierarchical chirality are presented together with their parametric study. Secondly, a series of mechanical metamaterials with programmable stiffness, shape modulation, and compression-twist mode are also developed with the waterbomb tube. Two characteristics including the programmability and controllability of the metamaterials are revealed with fundamental modeling of the metamaterials. Finally, potential applications of the proposed origami-based structures are discussed.
Biosketch of Speaker 3
Huijuan Feng is a Lecturer in the Department of Mechanical and Construction Engineering at Northumbria University. She obtained dual PhD degrees in Mechanical Engineering from both Université Clermont Auvergne (France) and Tianjin University (China), and BEng degrees in both Mechanical Engineering and Engineering Management from Tianjin University (China). Prior to joining Northumbria University, she was a postdoctoral researcher in École Polytechnique Fédérale de Lausanne (EPFL, Switzerland) from 2018 to 2020. Her research expertise centers on reconfigurable mechanisms and robotics, rigid origami structures and their applications in robotics, deployable structures and metamaterials.
Guest Host: Yunfang Yang
Dr. Yunfang Yang graduated from Engineering Science at University of Oxford in 2020. Her research involves using origami/kirigami mechanisms to design reconfigurable materials with interesting properties and performance. The materials she designs can change their shape, density, and elastic energy through transformation, which provide a variety of potential applications, from multifunctional metamaterials, soft robotics, to kinetic architecture. Yunfang gained her Bachelor's Degree from Tsinghua University, where she had a background in soft robotics and bio-printing. She is aiming to combine her knowledge in mechanism design with computational fabrication for smart active materials in the future.