Biomedical Engineering Reference
In-Depth Information
(a) Determine the stress field
(
x
).
(b) Determine the displacement field
u
(
x
). Assume that at
x
σ
=
the
displacement
u
(
) satisfies
u
(
)
=
0.
6.7
Consider a muscle/tendon complex as shown in the figure. To find out how
much the tendon and the muscle are extended when the complex as a whole
is loaded with a force
F
, a very crude two bar model can be used. The mus-
cle is modelled as a bar with length
1
, Young's modulus
E
1
and cross
section
A
1
. At point
B
the muscle is attached to the tendon, which is mod-
elled as a second bar with length
2
, Young's modulus
E
2
and cross section
A
2
. At point A the muscle is attached to the bone, which we consider as
a rigid fixation. At point C a force
F
is applied in the direction of the bar
(tendon).
muscle
tendon
A
C
B
F
l
2
,E
2
,A
2
l
1
,E
1
,A
1
(a) Determine the internal force in a cross section between A and B and
in a cross section between B and C.
(b) Determine the stress
σ
in a cross section between A and B and a cross
section between B and C.
(c) What happens with the calculated forces and stresses if the Young's
moduli of both muscle and tendon are reduced to half of their original
value?
(d) Determine the displacements at point B and C as a result of the
applied load
F
at point C.
