Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Derivation of the nonlinear bending-torsion model for a junction of
  elastic rods   In this paper we derive the one-dimensional bending-torsion equilibrium model
modeling the junction of straight rods. The starting point is a
three-dimensional nonlinear elasticity equilibrium problem written as a
minimization problem for a union of thin rod-like bodies. By taking the limit
as the thickness of the 3D rods goes to zero, and by using ideas from the
theory of $\Gamma$-convergence, we obtain that the resulting model consists of
the union of the usual one-dimensional nonlinear bending-torsion rod models
which satisfy the following transmission conditions at the junction point:
continuity of displacement and rotation of the cross-sections and balance of
contact forces and contact couples.

28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics