COFFEE BREAK - - - - - 16 . 30 - 17 . 00 - - - - - Second Afternoon Session (

The assessment of the ability of a mechanical system to tolerate defects is a typical multi-scale problem where the property of flaw tolerance emerges from the nonlinear interactions between the material constituents at the different scales, a common feature of complex systems. In the present talk, a critical analysis of the factors influencing flaw tolerance of continuum and discrete mechanical systems is proposed. At the continuum level, it is shown by extensive finite element simulations that the material heterogeneity plays a fundamental role and that a suitably tailored hierarchical microstructure can effectively enhance the flaw tolerance of the system. In discrete molecular systems, on the other hand, the nonlocality of the elementary interactions between molecules is the key parameter for enhancing the ability of the material to tolerate defects. A critical analysis of this phenomenon according to networks and graph theories is proposed to interpred the results of molecular dynamics simulations.