(Georgia Institute of Technology, 2018-04-19)
Mao, Xiaoming
When conventional brittle materials break, long cracks form due to stress focusing at crack tips: a phenomenon explained by Griffith in the 1920s. In this talk, we will discuss two types of systems where the fracturing process is “unconventional”. The first type are fiber networks. Using simulations we found that stress concentration never occurs in these networks. Instead, the network enters a steady state where force chains break and reform, leading to a divergent length scale. The second type are Maxwell lattices with domain walls hosting topologically protected states of self stress. Our simulations showed that stress and bond breaking events are concentrated on these domain walls, even in presence of cracks and deep into the nonlinear process of fracturing. We discuss how these ideas can be used in designing metamaterials that are protected against crack formation.