Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
M
Fig. 3
Reproduction of the opening angle experiment with prescribed opening angles
ʱ
=
A
.
[
]
ʱ
=
.
[
]
˃
ʸ
after
a
the application of the residual
45
0
deg
,
90
0
deg
. Circumferential Cauchy stress
strain field,
b
the radial cut
of the effect of different prescribed opening angles and radii which, for the purpose of
illustration, are set to values of
R
i
,
R
i
M
=
1
.
5
[
mm
]
=
2
.
5
[
mm
]
,
ʱ
=
45
.
0
[
deg
]
A
and
. As a consequence of the initial imposition of the residual
strain field, we obtain a stretching and warping of the cross-section of the tube. As
both layers are separated from each other, this consequently results in an undesired
penetration. In order to avoid this, a contact condition is prescribed between outer
media and inner adventitia in the first simulation step.
Figure
3
illustrates the contours of the circumferential Cauchy stress
ʱ
=
90
.
0
[
deg
]
˃
ʸ
at different
configurations
B
res
of the simulation for the perfect tube (Fig.
3
a, b) and the
perturbed tube (Fig.
3
c, d). It becomes apparent that the technique described above is
able to appropriately reproduce the prescribed input parameters, so that
R
isim
≈
B
0
and
R
i
,
R
isim
≈
R
i
M
M
and
A
A
and
0. Furthermore, the stress levels
approximately agree for both cases. This underlines that the assumption of a perfect
cylindrical tube is—in this case—a valid approximation for residual stress imposition
of a slightly perturbed tube as used in this contribution.
,
ʱ
sim
≈
ʱ
ʱ
sim
≈
ʱ
˃
ʸ
≈
