Appendix
E:
Mechanical dynamic loading
DLoG MPC 6
Manual
159
Here we have decided to use springs with an M8 thread and cylindrical body made of
natural rubber (NR). Based on the datasheet for a diameter of 30 mm and a height of 20
mm, for example, we arrived at the pressure load:
Compressive force 539 N / Displacement 1 mm = 539 N/mm for a Shore hardness A 70.
This value lies below the default value. What is the natural frequency?
The following formula can be used to calculate the natural frequency:
Where:
f
e
= natural frequency in Hz
c = total spring constant
= 539 N/mm (calculated from datasheet values)
* 3 (springs) / 22.5 (factor) = 71.9 N/mm
m = oscillatory mass
= 5 kg
This theoretical value of 19.1 Hz lies in the range of 20 Hz
±
5 Hz as measured in
practice.
The calculations depicted above are only approximations, which is why we recommend a
final
field test
with the selected elastomer springs .
Hz
m
c
f
e
1
.
19
03
,
5
=
⋅
≈
