Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Crack front dynamics: the interplay of singular geometry and crack
  instabilities   When fast cracks become unstable to microscopic branching (micro-branching),
fracture no longer occurs in an effective 2D medium. We follow in-plane crack
front dynamics via real-time measurements in brittle gels as micro-branching
unfolds and progresses. We first show that {\em spatially local} energy balance
quantitatively describes crack dynamics, even when translational invariance is
badly broken. Furthermore, our results explain micro-branch dynamics; why
micro-branches form along spatially localized chains and how finite-time
formation of cusps along the crack front leads to their death.

23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org