Another use for rubber, besides sealing and impact absorption, is vibration damping. This is where its natural elasticity is used to absorb vibrations rather than letting them spread through a machine or structure.
Most elastomeric materials will dampen vibration to an extent, although the reduction is related to vibration frequency. Vibration dampening rubber however is rubber that’s been optimized for the purpose of reducing vibration transmission.
Why Dampen Vibration?
Vibration in a structure can loosen fasteners, accelerate fatigue and cracking, and transmit sound. Thrumming in air ducts is an example of this last effect where air movement makes panels vibrate.
Vibration is reduced by placing an absorbent material between joints. As vibrations pass from the rigid members into this softer material, they make it compress and recover. This absorbs energy that would otherwise be transmitted through the structure.
In the case of vibrating panels the solution is a little different. Here the goal is to stop the panel moving. This is done by adding mass, often in the form of a heavy elastomeric (rubberlike) material. This might be bonded to the surface or can be sprayed on like a paint.
Vibration Dampening Rubber
Natural rubber or gum rubber makes an excellent vibration-absorbing material. Firmness is measured by durometer with lower durometer material being softer and more vibration-absorbing.
Gum rubber is flexible from -40°F but its upper limit is only around 140°F. It tends to harden when exposed to UV, so is best restricted to indoor applications. Its resistance to acids, alkalies, and citrates is good but it is attacked by oils, gasoline, and hydrocarbon solvents.
Closed cell rubber has excellent vibration dampening characteristics with the cell walls acting like micro-springs. It does however lack strength and can be damaged if over-compressed.
Damping or Dampening? Hennig Doesn’t Mind
We have it on good authority that either word works. “Dampen” means to reduce, which is why some people prefer that to “damping” which is the act of dampening. Whichever you like to use is fine with us. Just remember to consult our specialists for your vibration dampening rubber needs.
