Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Torsion instability of soft solid cylinders   The application of pure torsion to a long and thin cylindrical rod is known
to provoke a twisting instability, evolving from an initial kink to a knot. In
the torsional parallel-plate rheometry of stubby cylinders, the geometrical
constraints impose zero displacement of the axis of the cylinder, preventing
the occurrence of such twisting instability. Under these experimental
conditions, wrinkles occur on the cylinder's surface at a given critical angle
of torsion. Here we investigate this subclass of elastic instability--which we
call torsion instability--of soft cylinders subject to a combined finite axial
stretch and torsion, by applying the theory of incremental elastic deformation
superimposed on finite strains. We formulate the incremental boundary elastic
problem in the Stroh differential form, and use the surface impedance method to
build a robust numerical procedure for deriving the marginal stability curves.
We present the results for a Mooney-Rivlin material and study the influence of
the material parameters on the elastic bifurcation.

23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con