Reporter : Professor Yihui Zhang (Department of Engineering Mechanics, School of Aeronautics and Astronautics, Tsinghua University)

Time: October 18, 2021 (Monday) 14:30—16:00

Venue: Room 529, Building A18, Ming Palace Campus

Sponsor: State Key Laboratory of Mechanical Structural Mechanics and Control, Key Laboratory of Multifunctional Lightweight Materials and Structures of the Ministry of Industry and Information Technology, School of Aviation, Association for Science and Technology

Summary of report content:

   By learning from or breaking through the microstructures in natural organic biological systems, it is expected to realize biomimetic soft materials with similar mechanical properties, and even realize unconventional mechanical and physical properties that natural materials do not have (such as negative Poisson's ratio, negative swelling, etc.) , has a very important application prospect in the fields of biomedical devices, tissue engineering, soft robots and so on. However, many biological soft materials in nature have very complex microstructures, and sometimes also exhibit certain random distribution characteristics, making their bionic design very challenging. This report focuses on the design and fabrication of mechanically driven unconventional mesh soft materials. On the one hand, the design of biomimetic soft materials inspired by the microstructure of the collagen tissue of the organism will be introduced. complex mechanical behavior, and through the establishment of a nonlinear mesoscopic mechanical theory of bionic mesh soft materials, the dependence between key mechanical properties such as elastic modulus and elongation and the microstructural configuration is revealed, which can accurately match the skin and heart. Defect-insensitive biomimetic materials for tissue stress-strain curves. On the other hand, the concept of multi-level lattice design that introduces arbitrary curvilinear microstructures, structured rotating nodes and composite microstructures into periodic network materials will be introduced, and the nonlinearity of multilevel lattice-based soft mechanics metamaterials will be established. Deformation theory and design method, prepared network metamaterials with unconventional properties such as super large negative swelling, anisotropic negative swelling, programmable multi-stable, thermally induced pure shear, etc., and also achieved a Poisson's ratio of -1 Precise tuning in the range to 1 and large deformation isotropic properties. Finally, this report will introduce the applications of the developed mesh soft materials in biointegrated devices and other fields, including multifunctional biomimetic electronic skins matching the mechanical properties of human epidermis and hemostatic bandages that can promote skin regeneration.

Brief introduction of the reporter:

       Yihui Zhang is a tenured professor at Tsinghua University. He received his bachelor and doctorate degrees from Nanjing University of Aeronautics and Astronautics and Tsinghua University in 2006 and 2011, respectively. From 2011 to 2015, he served as a postdoctoral fellow and a research assistant professor in the Department of Civil and Environmental Engineering at Northwestern University. He has long been engaged in research in the fields of soft matter mechanics, 3D microstructure assembly, and flexible electronic device mechanics. He has published more than 140 academic papers, which have been cited more than 10,000 times by him; 5 Chinese invention patents and 3 American invention patents have been authorized. As the corresponding author, relevant results have been published in high-level journals such as JMPS, IJSS, Nature, Science, Nature Materials, Nature Reviews Materials, Nature Electronics, NSR, Nature Communications, Science Advances, PNAS, Advanced Materials, etc. He has won the Science Exploration Award, the MIT Technology Review Global 35 Innovators Under 35, the National Natural Science Foundation of American Society of Mechanical Engineers Sia Nemat-Nasser Early Career Award, American Society of Mechanical Engineers Melville Medal, Eshelby Young Professor of Mechanics Award, Hong Kong Qiushi Technology Foundation Outstanding Young Scholar Award, Clarivate Analytics Highly Cited Scholar and other honors. He is also the Associate Editor of Science Advances, Mechanics of Materials, Journal of Applied Mechanics and Research, member of the Executive Committee of the International Association of Engineering Sciences, Deputy Head of the Working Group of Electromagnetic Device Mechanics and the Working Group of Soft Matter Mechanics of the Chinese Society of Mechanics.