Mass-load by accelerometers in composite panels

[washdelima]

I am measuring some FRF in a composite panel. I would like to know if somebody knows how to eliminate the accelerometer mass-load effect in my measurement.

 

[IRstuff]

I would think that if your acceleromter is so heavy that it affects the measurement, then you need to do it some other way. You could be changing the resonance.

TTFN

FAQ731-376

 

[GregLocock]

The trick to estimate the effect is to measure as is, then bond some more accelerometers on and see if it changes the frequencies.

You could use any number of non contacting sensors instead. Laser doppler methods are a nice way for flat panels.




Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[SomptingGuy]

We use proximity sensors (magnetic, inductive) when wanting to measure motions of things we can't touch.

- Steve

 

[Rob45]

The scanning laser vibrometer has a 3D version good even if the part is not a flat panel.

But the usual test for mass loading is to add one more accelerometer of the same type, possibly even on top of the first one, retest and see if the frequency changes.
If not, you have no appreciable mass-loading effect.