Avalanche localization and universality class of amorphous plasticity


Zoe Budrikis
The Statistical Materials Modeling Laboratory

Thursday, 29. January 2014, 17.00
WW8, Raum 2.018, Dr.-Mack-Str. 77, Fürth

Plasticity on the microscale displays intrinsic fluctuations and localization. This behaviour can be captured by a model for 2D amorphous plasticity with random local yield stresses and long-range quadrupolar interactions. This model is similar to models for depinning of an elastic interface moving in the transverse direction, and plastic strain increases in a series of avalanches with power law size distribution. However, the universality class of the model is yet to be firmly established. In particular, because the interactions are long-range one would expect mean field behaviour, but distinctly non mean field behaviour has been reported previously [1].
By simulating substantially larger systems than have previously been studied [2], we are able to more accurately determine exponents characterizing, eg, avalanche sizes. We show that as the external stress increases towards the yielding phase transition, the scaling behavior of the avalanches crosses over from mean field theory to a different universality class. This behavior is associated with strain localization, which significantly depends on the short-range properties of the interaction kernel.


[1] Talamali et al, Phys. Rev. E 84, 016115 (2011)

[2] Budrikis and Zapperi, Phys. Rev. E 88, 062403 (2013)