Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Onset of Plasticity in Thin Polystyrene Films   Polymer glasses have numerous advantageous mechanical properties in
comparison to other materials. One of the most useful is the high degree of
toughness that can be achieved due to significant yield occurring in the
material. Remarkably, the onset of plasticity in polymeric materials is very
poorly quantified, despite its importance as the ultimate limit of purely
elastic behavior. Here we report the results of a novel experiment which is
extremely sensitive to the onset of yield and discuss its impact on measurement
and elastic theory. In particular, we use an elastic instability to locally
bend and impart a \textit{local} tensile stress in a thin, glassy polystyrene
film, and directly measure the resulting residual stress caused by the bending.
We show that plastic failure is initiated at extremely low strains, of order
$10^{-3}$ for polystyrene. Not only is this critical strain found to be small
in comparison to bulk measurement, we show that it is influenced by thin film
confinement - leading to an increase in the critical strain for plastic failure
as film thickness approaches zero.

2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ