To see how we've managed to completely cure many resonance problems using simple, bolt-on modifications goto the Tuned Dampers page.
When troubleshooting problems of vibration, UNIVIB engineers
frequently discover that, while a troublesome vibration can be traced
to a specific exciter such as a gear mesh or bearing "defect"
there is nothing abnormal about the condition of that exciter. The problem,
in these situations, is often caused as a result of resonant amplification
of the vibration in which, at certain operating speeds, the "normal"
vibrations are magnified by the structural resonances to abnormal
levels. In these situations, simply replacing the gear or the bearing
that is the source of the vibration will not provide a solution. Instead,
it is essential that modal analysis be carried out in order to identify
the mode shapes so that the areas that require stiffening or damping can
be readily pinpointed.
We have, over the years, carried out many hundred such modal analyses on structures ranging in size from as small as a boring bar to as large as an overhead gantry crane. We have at our disposal a range of shakers and hammers to excite the structure under test and can often complete the data collection over the course of just a few hours thus keeping down-time to a minimum.
click here to see an animation of the five major resonant modes of vibration of a vertical machining centre, shown in order of ascending frequency.
Resonance can be a wonderful thing! Virtually all musical instruments depend on the principle, so just think how little music there would be without it. In most other walks of life, however, especially the working environment, the presence of resonance is usually undesirable. All mechanical structures and drive-trains, including manufacturing machinery, like to vibrate at their own natural frequencies and with characteristic mode shapes governed by their geometric form. Modal analysis is an experimental technique that is used to identify the mode shape of a structure as it vibrates at resonance. It is an essential process if there is a requirement to understand the resonant behaviour of a structure so that steps can be taken to improve it.