Damping Measurement: Shaker Table vs Ping Test
Damping Measurement: Shaker Table vs Ping Test
(OP)
I'm interested in performing a vibration test on a piece of hardware; we're quite interested in damping, specifically.
I'm looking for a comparison of the accuracy of damping measurements with a shaker test vs a hammer test. Shaker tests seem as though they would be more accurate, as you control the forcing amplitude, rather than interpolate the damping from the response. But, this is mere conjuncture on my part. Comments?
I'm looking for a comparison of the accuracy of damping measurements with a shaker test vs a hammer test. Shaker tests seem as though they would be more accurate, as you control the forcing amplitude, rather than interpolate the damping from the response. But, this is mere conjuncture on my part. Comments?





RE: Damping Measurement: Shaker Table vs Ping Test
Cheers
Greg Locock
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RE: Damping Measurement: Shaker Table vs Ping Test
RE: Damping Measurement: Shaker Table vs Ping Test
Recently I have been doing quite a lot of damping material tests, to screen candidate materials for a new application. Not having a shaker, I have done this using my trusty hammer. I devised a panel test using the same substrate material & thickness as the intended application, and I sized the panel to achieve approximately the same first mode frequency as the problem frequency in our structure. Using LMS TestLab software, which calculates the damping ratio directly, I have gotten very consistent results, with good repeatability. And I have run several manual calculations of the half-power bandwidth of the FRFs to assure that the software IS calculating correctly.
The issue I have run into, however, is that my principal supplier uses the B&K modal package to calculate damping ratio, and they occasionally get very different results.
But repeatable ones. No conversion factor is possible, though, because they also sometimes get identical results to what I get.
I guess we're stuck without access to a shaker. I may ask them to see what sort of results they'd get using their shaker.
Best regards,
- R
RE: Damping Measurement: Shaker Table vs Ping Test