ELFT HÍRADÓ

[Kormányos Andor <andor.kormanyos AT ttk.elte.hu>]

ELTE TTK Fizikai Intézet / ELTE Institute of Physics


ORTVAY KOLLOKVIUM / ORTVAY COLLOQUIUM

(https://physics.elte.hu/ortvayseminar)


Thursday, 17th November  2022, 15:00h.


Pócza Jenő Classroom,  Physics Building 1.71

Pázmány Péter sétány 1/A, 1117 Budapest.


Ferenc  Kun (University of Debrecen)
Controlled fracture patterns in shrinkage induced cracking

Shrinkage induced cracking is abundant in nature giving rise to the formation 
of spectacular polygonal crack patterns for instance in dried lake beds, in 
permafrost regions on Earth and Mars, and in cooling volcanic lava. The 
simplest realization of such crack patterns can be achieved in the laboratory 
by desiccating thin layers of dense suspensions such as coffee, clay, or 
calcium carbonate on a rigid substrate where the gradual solidification leads 
to shrinkage stresses and cracking. Recently, a promising method of the 
generation of controlled crack patterns has been suggested by applying 
mechanical excitation to dense suspensions before desiccation sets in. Due to 
its technological potential, we investigate such possibilities of crack 
patterning in the framework of a discrete element model focusing on the 
temporal and spatial evolution of anisotropic crack patterns as a thin 
material layer gradually shrinks. In the model a homogeneous material is 
considered with an inherent structural disorder where anisotropy is captured 
by the directional dependence of the local cohesive strength. Based on 
computer simulations and analytical calculations we explore how the structure 
of the crack pattern and the shape of emerging fragments evolve as the 
strength of anisotropy is varied, and determine those features of the system, 
which remain robust at any degree of anisotropy. In particular, we 
demonstrate that cracking of the layer proceeds in bursts of activity with 
scale free statistics similar to a broad class of fracture phenomena.


The seminar can also be followed via Microsoft Teams:

https://teams.microsoft.com/l/meetup-join/19%3a6ea3c606f9b94c9d842740bb24c3cf6e%40thread.tacv2/1668174128711?context=%7b%22Tid%22%3a%22b366dbcd-4fc3-4451-82d2-e239564302c3%22%2c%22Oid%22%3a%22560bcc66-85b7-4700-9055-41903a3659ca%22%7d

Best regards,
Andor Kormányos
coordinator