Minimize Mechanical Vibrations with Highly Damped Elastomers
On the surface, it would seem that reducing unwanted vibrations in a device would be easy: just slap some rubber under the offending component and call it a day. However, the specifics of energy transmission are much more complex. A poorly designed solution can actually increase vibrations, intensifying symptoms such as damaging surrounding components or noise radiating from the structure.
Isolators will often be used on kinetic components to reduce those symptoms. Put simply, the goal is to minimize transmissibility, or the ratio of mechanical energy output to the mechanical energy generated. That measure of transmissibility is influenced by many factors including frequency, temperature, the material’s modulus, the isolator’s shape factor, spring rate, natural frequency, and so on (learn more here). Because of so many unique factors, the best performing isolators are often those which minimize transmissibility across a spectrum of structural and environmental variables.
This is where the misguidedness of the hypothetical above comes to light. Generic, low-damped materials can perform perfectly well as isolators – so long as conditions remain stable to keep the them within the isolation region of a transmissibility curve. However, “stable conditions” aren’t usually the hallmark of electronic devices. Operating temperatures vary. Motors and fans increase and decrease in speed. Impact events occur with lesser or greater force (if only your smartphone could talk…). When conditions are right (or wrong?) the energy output can be amplified by 2x, 3x, or even much greater.
Highly damped materials, such as ISODAMP™ C-8000 Series Elastomers, are specifically engineered to minimize transmissibility with that variability in mind.
(Image source: Aearo Technologies (a 3M Company))
Damped elastomers work to minimize potentially damaging vibrations whether the system is in the isolation region or during peak resonance. High damping is able to effectively limit the large amplifying response seen in low-damped materials, resulting in less headaches for design engineers.
*Note: Damping materials do not actually reduce headaches. Please take medication for headaches.
About this author
Kathy Hutton, Product Manager at Digi-Key Electronics, has been with Digi-Key since 2003 and has responsibilities for interconnect, passive and electromechanical products. She is in daily communications with engineers/customers (both internal and external) to help drive sales with her extensive product knowledge. Kathy holds an Electrical/Automation Technical Degree and was part of the Digi-Key Applications Engineering team prior to her role in Product Management. Outside of work, she is an avid fisherwoman, both competitively and just for some fun on the water.
