SISSA Colloquium: Failures and Catastrophes in Strained Amorphous Solid

A lecture by Itamar Procaccia of the Weizmann Institute of Science, Israel

16 January, 3.30 pm
SISSA, "P. Budinich" Main Lecture Hall

The mechanical failure of amorphous media is a ubiquitous phenomenon from material engineering to geology. It has been noticed for a long time that the phenomenon is “scale-free”, indicating some type of criticality. In spite of attempts to invoke “Self-Organized Criticality”, the physical origin of this criticality, and also its universal nature, being quite insensitive to the nature of microscopic interactions, remained elusive. Recently Itamar Procaccia and collaborators proposed that the precise nature of this critical behavior is manifested by a spinodal point of a thermodynamic phase transition. Demonstrating this requires the introduction of an "order parameter" that is suitable for distinguishing between disordered amorphous systems. At the spinodal point there exists a divergent correlation length which is associated with the system-spanning instabilities (known also as shear bands) which are typical to the mechanical yield. The theory, the order parameter used and the correlation functions which exhibit the divergent correlation length are universal in nature and can be applied to any amorphous solid that undergoes mechanical yield.

This Colloquium is still part of the celebration of the School's 40th Anniversary. Colloquia are intended as a moment of interdisciplinary exchange and a way to reaffirm the sense of belonging to our community.