Vibration and noise are an ever-present problem in the majority of
mechanical systems, from consumer products to precision manufacturing
systems. But most approaches for vibration suppression are expensive and
invasive, so only a small subset of the techniques developed in research
labs are widely used.
Viscoelastic sandwich layers are perhaps the most commonly applied damping
treatment. I will outline the basic principle of their operation and show
some extensions to 3D vibrating frames. Although the conventional
operation of these dampers can be understood from a quasi-static analysis,
I will give examples where the dynamic interaction of the structure and
sandwich layer leads to some surprising results.
Dynamic vibration absorbers (or tuned-mass dampers) are far less
intrusive, but must be carefully tuned to be effective. I will highlight
their application to ultra-precision optical mounts, where the vibration
is inherently three dimensional and show how the concept of the tuned-mass
damper can be extended to multiple modes in multiple planes by the
coupling of rotation and translation. Taking this concept further, I show
how the coupling of translation and rotation can be used to make the
absorber appear to have a large mass and therefore perform far better than
a conventional absorber.
Finally, I show how dynamic coupling of a structure and a low-density,
low-wave-speed material (such as a granular material or foam) can be used
to make a low cost, robust, and unobtrusive method for broad-band
vibration suppression. The approach is compared to other quasi-static and
dynamic damping approaches and applications to precision machines and
servomechanisms are outlined.
