ネットワーク状弾性体のトポロジカルメカニクスと強靭化

抄録

Network-like materials are made of sparse elastic networks. The network-like materials can be found in our daily lives, such as graphene, rubber, hydrogel, foam, mesh, net, torus etc. Toughening of such materials is one of the most important problems in materials science and structural mechanics, and there have been many studies so far. For example, novel types of tough hydrogels have been developed by material scientists in the last decade. However, the toughening principle is not well established: most researchers pay much attention to chain length heterogeneity, but little attention to other aspects. In this study, we focus on network topology, which is believed to be essential in the field of complex network. We create macroscopic polymer models made of rubber strings and connecters, and perform fracture experiments of such model polymers with different topological structures. We find that periodic but systematic modifications in local coordination number with keeping the constant mean number (4, in 2D) exhibit great improvement in toughness compared with regular square lattices. Furthermore, the star polymer network shows the best performance. In our talk, we will explain the details of our experiments and discuss the results by comparing with numerical simulations. If time permits, we will report our recent experiments using mechanical meta-materials.