Vibration Isolation - Transmissibility

Vibration Isolation - Transmissibility



Transmissibility(dB) v Frequency(Hz)


Notes:

1] Java browser required such as Netscape 2/3 or IE 3 or above. There may be a slight problem with Netscape 3 (Windows) as the scrollbars are moved. This is due to the production of continual scrolling interrupts in the Netscape 3 AWT; however results should be unaffected. The unix versions of Netscape cope easily with these scrolling interrupts


2]The 3 scrollbars in the program above will adjust mass, stiffness and damping in a simple vibrating system as shown in the schematic diagram below. The transmissibility curve indicates how vibration can be isolated by altering these parameters. Isolation is best achieved by ensuring forced vibration frequencies are well above the natural resonance. Damping needs to be high enough to control unwanted resonance, for example as a machine starts up or slows down, but not so high as to reduce isolation efficiency at higher frequencies.

3] Ranges and adjustment

Mass 0.1 kg to 1000 kg in 0.1 kg steps
Stiffness 10 N/m to 100000 N/m in 10 N/m steps
Damping ratio 0.01 to 1 in 0.01 steps

Coarse adjustment - click on scoll button and drag to new position
Medium adjustment - click on bar either side of button to move 10 steps
Fine adjustment - click on arrows to left or right of scrollbar to move 1 step

4] For very low damping ratios (<= 0.02) there may be some loss of precision for maximum transmissibility

5] No guarantee of any kind whatsoever for this software.


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