Biomedical Engineering Reference
In-Depth Information
Normal force,
F
N
Top plate
Bottom plate
Figure 3.20
The experimental setup used to measure friction coefficients. PVDF films were
adhered to both sides of the mid-plate. The friction surfaces were attached to the internal surfaces
of the top and bottom plates
Table 3.3
List of abrasive materials and their corresponding friction coefficients
Surface
Black dry
PTFE
Stationery
Abrasive
Abrasive
Abrasive
Abrasive
film
tape
paper
2000
1200
800
240
μ
0.11
0.19
0.29
0.35
0.40
0.44
0.55
was tested against the PVDF film. However, the tested PVDF film was metalized with
aluminum so it was this coating that was considered to be the real contact surface in
the tests. Table 3.3 shows the tested materials and their corresponding static friction
coefficients established through testing.
3.9.2 Experiments Performed on Sandwiched PVDF for Different Surface
Roughness
An experimental setup, as illustrated in Figure 3.21, was used to apply a known load to a
PVDF film pressed between two friction surfaces. A square-shaped 110 μm-thick PVDF
film was placed between two thick plates of Plexiglas and the mentioned pre-characterized
surfaces were applied one by one between the plates and the top and bottom surfaces of
the PVDF film, as shown in Figure 3.22.
A 20 N load, at a frequency of 20 Hz was applied to the top Plexiglas. Considering
the area of the PVDF film (30 mm
×
30 mm), the maximum pressure exerted on the film
was about 22 kPa. A picture of the experimental setup is shown in Figure 3.23.
