Can anyone recommend an inexpensive small triaxial accelerometer? 1

[CaptainCrunch]

Im looking into a good generic lightwieght (3-8 grams) triaxial accelerometer, that is moderately priced. I need it for modal testing and damping ratios on a lightwieght muffler structure (for room temperature testing only). A good vendor name or model number woyuld be greatly appreciated.

 

[GregLocock]

Not too sure about weights but Bruel & Kjaer and Endevco spring to mind. In the UK DJ Birchall used to make a small relatively cheap triax.

If you are trying to get the panel modes of the muffler boxes then you could use uniaxials to get the mass down, plus the 'in plane' response is not needed.

I wouldn't sweat the weight too much, exhausts are pretty thick skinned and highly curved.


Cheers

Greg Locock

 

[ronfrend]

Try the MSI site for low cost, low weight accels.

http://www.msiusa.com/piezo_documentation.htm

They have single and 3 channels accels with response of <0.5Hz to >2kHz and some go up to over 10kHz. Typical cost is about $25 (uncanned but usable). They don't need a constant current supply but they DO need a steady voltage supply +5Vdc.

I think these should be ideal for your application but let me know how you get on. I have been looking for low cost accels for a while as (like most of us now) the high cost of most accels is killing the on line monitoring system. To date these are the best I have come across but make sure you look at the frequency response carefully as the reponse is not perfectly linear on all of these accels.

Ron Frend
ron.frend@predicon.net

 

[Rob45]

You might consider whether you really need triaxial accelerometers for muffler analysis. Having done quite a bit of this sort of work over the past 20 years or so, I've seldom run across a structure that required them.
If you're really interested in &quot;muffler structre&quot; as you say, it's quite likely that the modes perpendicular to the muffler surface will be the only ones of interest. If it's the total system response you're looking for, the vertical mode is the only one likely to be of any interest, since the system supports should have extremely high compliance in the transverse directions.

 

[CaptainCrunch]

Hello,

Further info I probably should have provided initially. The muffler is in a small engine application. The entire muffler assembly weighs ~ 1.3 lb. It is attached directly to the exhaust port of cylinder head. So it is not a strapped auto muffler. The muffler assembly is squarish with large flats (which will oil-can). the sheet thickness of components are .040&quot;. Hence my concern about the weight of the triax. Hence my concern about the weight.

The modal analysis from my part would be useful to correlate data to FEA results. I guess if I didnt want to do that I could just have on triax in the middle of the flat top. Because the muffler is rigidly attach to the cylinder head it recieves significant vibration in all three directions, so I think the triax is still needed. (granted that the most deflection is normal to the sheet plane.

Anyhoo, thanks for the repsonses and TIA for any more

George