Biomedical Engineering Reference
In-Depth Information
A
F
P
P
B
Figure 3.4
A loaded body.
A
H
A
H
A
V
P
l
y
V
B
V
B
P
H
P
l
y
H
B
H
B
B
l
x
y
x
Figure 3.5
Free body diagram of the simple loaded body.
−
H
P
−
H
A
−
0
V
P
+
V
B
=
0.
H
B
=
The above expressions represent two equations with three unknowns (
H
A
,
H
B
and
V
B
), being insufficient to determine these. However, the sum of the moments with
respect to an arbitrary point has be zero as well. Computing the resulting moment
with respect to point A gives
−
2
l
y
H
B
−
l
y
H
P
−
l
x
V
P
=
0.
This yields
one
additional equation such that the unknown reaction forces may be
determined.
The above procedure is not unique in the sense that different points can be used
with respect to which the sum of moments should be required to be zero. For
instance, rather than using the sum of moments with respect to point A, the sum
of moments with respect to point P could have been used.
