Biomedical Engineering Reference
In-Depth Information
TABLE 4.11
Spring Specification
Outside
diameter
(mm)
Wire
diameter
(mm)
Max
load
(
N
)
Free
length
(mm)
Max
length
(mm)
Initial
tension
(
N
)
Rate
(
N
/mm)
Material
4.775
0.355
2.962
25.400
0.033
109.219
0.146
SS
4.775
0.355
2.962
34.925
0.021
163.703
0.146
SS
4.775
0.355
2.962
57.150
0.012
298.450
0.146
SS
FIGURE 4.140
PAN fiber bundle muscles in action as a single finger.
muscles, one return spring, and two tubes. The finger body is made of acrylic with
thickness of 3 mm. Figure 4.140 shows one PAN finger in a contracted state. Detailed
dimensions of finger joint and assembly drawings are included.
The final configuration of a five-fingered hand equipped with five pairs of PAN
fiber bundle muscles is shown in figures 4.141a, 4.141b, 4.142a, and 4.142b. Figure
4.143 depicts the detailed line drawings pertaining to the designed and fabricated
five-fingered hand equipped with contractile PAN fiber bundle ionic polymeric
muscle design.
4.7.2
A
DDITIONAL
M
ECHANICAL
P
ROPERTY
M
EASUREMENT
OF
S
INGLE
PAN F
IBER
Mechanical properties of PAN fiber muscle were measured. PAN fibers were
oxidized at 220
C for 30 min. Ten
samples were tested for both elongated and contracted states. A typical stress-strain
curve is shown in figure 4.144. It was found that, above 80
°
C and then saponified in 1
M
LiOH at 75
°
C saponification
temperature, fibers were completely transformed to a gel-like substance and
mechanical properties became hard to measure. The contracted state and elongated
state exhibited different mechanical properties. Table 4.12 summarizes the mechan-
ical properties of each status.
°
