题目：Topology design for advanced materials: case studies withtough graphene andhydrogels
报告人：Dr.Teng Zhang，Mechanical and Aerospace Engineering, Syracuse University
时间：2016年6月14日14:00
地点：综合实验1号楼602会议室
Abstract:
Topological structures (disclination, dislocation, grain boundary, polymer networks, and hybrid hard-soft materials) have been found to significantly enhance the fracture toughness of graphene, hydrogels and force-bearing materials in human bodies such as bone, tendon, and cartilage. Mechanics modeling and simulation play essential roles in manipulating the topology in materials and structures, which requires a fundamental understanding of defect initiation, evolution, interaction;material fracture;large nonlinear deformationandmultiscaleand multiphysics coupling.
In this talk, I will demonstrate the principle of topology design viaexamples oftough graphene and hydrogels. For graphene (an extremely stiff material), molecular dynamics (MD) simulationsshow that a designed sinusoidal graphene structurecontainingperiodically distributed disclination quadrupoles has amode I fracture toughness around25.0 J/m2, about twice that of the pristine graphene. For hydrogels (very compliant materials), I will present a coupled cohesivezone and a Mullins-effect continuum model capable of quantitatively predicting the fracture energy. The proposed model is quantitatively validated with experiments on the hydrogels with topological structures of double networksand can thus guide the design of new soft tough materials. These findings demonstrate the impacts of manipulating topological structures on the mechanical properties of both hard and soft materials and reveal a promising strategy for designing advanced materials.
Bio:
Dr. Teng Zhang is an assistant professor in the Mechanical and Aerospace Engineering department at Syracuse University. Prior to Joining Syracuse, he was a Postdoctoral associate in the Department of Mechanical Engineering at MIT, working with Prof. Xuanhe Zhao. He received his PhD degree at Brown University (2015) with Prof. Huajian Gao, and his Master (2010) as well as Bachelor (2007) degrees at Dalian University of Technology, China. His research focuses on the multiscale modeling and simulation of soft materials (e.g., hydrogels), two-dimensional nanostructures (e.g., graphene) and bio-inspired design.
