Biomedical Engineering Reference
In-Depth Information
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
F
x
[N]
F
y
[N]
5
10
15
20
y
[cm]
Figure 4.9
Forces in the horizontal and vertical direction exerted on the spring in point B to displace point B in
the
y
-direction.
B
B
0
y
e
y
e
y
y
α
0
A
A
e
x
e
x
0
cos(
α
0
)
α
0
)
0
cos(
(a)
(b)
Figure 4.10
(a) Linearly elastic spring in the undeformed configuration oriented at an angle
α
0
with respect to
e
x
, fixed at A and free to translate in the
e
y
-direction at point B (b) Spring in the deformed
configuration.
coordinate system is located at point A. If point B is moved in the vertical direc-
tion, the force in the spring is computed assuming linear elasticity according to
Eq. (
4.19
). The unstretched length of the spring is denoted by
0
such that the
current position of point B follows from
x
B
=
0
cos(
α
0
)
e
x
+
ye
y
.
Point A is positioned at the origin:
x
A
=
0.
The current length of the spring satisfies
(
α
0
))
2
y
2
.
=|
x
B
−
x
A
|=
0
cos(
+
