Could engineers have known ahead of time exactly how much pressure the levees protecting New Orleans would be able to withstand before giving way? Is it possible to predict when and under what conditions material wear and tear will become critical, causing planes to crash or bridges to collapse? Weizmann Institute scientists have taken a new and original approach to the study of how materials fracture and crack.
Physicists attempting to find a formula for the dynamics of cracking have faced a serious obstacle. The difficulty lies in pinning down, objectively, the fundamental directionality of the cracking process: From any given angle of observation or starting point of measurement, the crack will look different and yield different results. Until now, no one has successfully managed to come up with a method for analyzing the progression of a forming crack.
To address this problem, Prof. Itamar Procaccia and research students Eran Bouchbinder and Shani Sela of the Chemical Physics Department first divided up the cracks' ridged surfaces into mathematically determined sectors. For each sector they were able to measure and evaluate different aspects of the crack's formation and assign it simple directional properties. After some complex data analysis of the combined information from all the sectors, the team found their method allowed them to gain a deeper understanding of the process of cracking, no matter which direction the measurements started from. They then successfully applied the method to a variety of materials - plastic, glass and metal.
The team's method will give engineers and materials scientists new tools to understand how basic materials act under different stresses, to predict how and when microscopic or internal, unseen fractures might turn life-threatening, or to improve these materials to make them more resistant to the formation or spread of cracks.
Prof. Itamar Procaccia's research is supported by the Minerva Center for Nonlinear Physics of Complex Systems; and the Naftali and Anna Backenroth-Bronicki Fund for Research in Chaos and Complexity. Prof. Procaccia is the incumbent of the Barbara and Morris L. Levinson Professorial Chair in Chemical Physics.