Dynamic Vibration Absorber

Kishore kumar posted:

Give https://www.maintenance.org/fi...861270/S___DA_R8.ppt a try.

Kishore kumar posted:

Dear John ,

Its a good example but what about the DVA calculations for this particular example ,it might be useful to better understand.

Use the tools on the forum!

Float your cursor over the spyglass at the right of the toolbar, select Advanced Search.  Then in the field Contains All of These Words insert dynamic absorber spreadsheet.  Scroll down and hit the search button.  I think the first hit is the spreadsheet you want but there are several that are listed.

 

"structural minute structural looseness" I am not sure of this terminology.

If there are high vibrations as result of resonant amplification, and DVA reduces vibration levels, then the secondary effect of looseness may diminish as well. It is advised to tighten loose structure first before testing for resonant structure and applying DVA or other corrective modifications.

Walt

In short yes. We had a section of framework vibrating at some alarming amplitudes when the would push into certain speed ranges, after verifying roll balance and alignment conditions we were left with a bump test that provided us with a confirmation of resonance at that frequency range. Some calculating and welding later, we built an absorber that keeps the I-beam steady and it does all the shaking. We actually built a couple and have 2 on at once. As 1 breaks after so many cycles at least we still have another and don't get caught with the 1.5 In/sec vibration unmitigated by an absorber.

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