Transition of rupture mode of strain crystallizing elastomers in tensile edge-crack tests
We revisit the classical results that the fracture energy density ( W b ) of strain crystallizing (SC) elastomers exhibits an abrupt change at a characteristic value ( ) of initial notch length ( c 0 ) in tensile edge-crack tests. We elucidate that the abrupt change of W b reflects the transition in...
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Published in | Soft matter Vol. 19; no. 1; pp. 1966 - 1976 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
08.03.2023
|
Subjects | |
Online Access | Get full text |
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Summary: | We revisit the classical results that the fracture energy density (
W
b
) of strain crystallizing (SC) elastomers exhibits an abrupt change at a characteristic value (
) of initial notch length (
c
0
) in tensile edge-crack tests. We elucidate that the abrupt change of
W
b
reflects the transition in rupture mode between the catastrophic crack growth without a significant SIC effect at
c
0
>
and the crack growth like that under cyclic loading (d
c
/d
n
mode) at
c
0
<
as a result of a pronounced SIC effect near the crack tip. At
c
0
<
, the tearing energy (
G
) was considerably enhanced by hardening
via
SIC near the crack tip, preventing and postponing catastrophic crack growth. The fracture dominated by the d
c
/d
n
mode at
c
0
<
was validated by the
c
0
-dependent
G
characterized by
G
= (
c
0
/
B
)
1/2
/2 and the specific striations on the fracture surface. As the theory expects, coefficient
B
quantitatively agreed with the result of a separate cyclic loading test using the same specimen. We propose the methodology to quantify the tearing energy enhanced
via
SIC (
G
SIC
) and to evaluate the dependence of
G
SIC
on ambient temperature (
T
) and strain rate (
&z.egrda;
). The disappearance of the transition feature in the
W
b
-
c
0
relationships enables us to estimate definitely the upper limits of the SIC effects for
T
(
T
*) and
&z.egrda;
(
&z.egrda;
*). Comparisons of the
G
SIC
,
T
*, and
&z.egrda;
* values between natural rubber (NR) and its synthetic analog reveal the superior reinforcement effect
via
SIC in NR.
We revisit the classical results that the fracture energy density (
W
b
) of strain crystallizing (SC) elastomers exhibits an abrupt change at a characteristic value (
) of initial notch length (
c
0
) in tensile edge-crack tests. |
---|---|
Bibliography: | 0 1 in the edge-crack test. See DOI c Electronic supplementary information (ESI) available: Tensile force-displacement curves for NR-B with various values at 25 °C with a strain rate of 0.11 s https://doi.org/10.1039/d3sm00060e ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1744-683X 1744-6848 |
DOI: | 10.1039/d3sm00060e |