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I need to design a vibration table (approx. 1000mx1000mm) to test products between 7-200Hz.

I was wondering if it is recommended to make the table structure from standardised, extruded aluminum profiles bolted together to reduce the cost (material + time) or does one have to go with a welded structure?

Yes, I am aware of the results of the Junker vibration test with regards to bolted connections and it seems like a bad idea because all the fasteners would loosen. However, maybe there is a workaround to use these aluminum profiles?

I sincerely appreciate any advice and/or previous experiences with these.

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  • $\begingroup$ The basic requirement is that the table itself has no dynamic response in the frequency range you want to test. It also needs to withstand the weight of the test pieces, times the "g" loads you will encounter during testing. Bolting together some aluminium extrusions sounds optimistic, unless you are only going to test light objects at low vibration levels. $\endgroup$
    – alephzero
    Feb 24 '19 at 16:10
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    $\begingroup$ Are the dimensions for your proposed table correct 1000x1000 m is 1x1 km. That's huge! $\endgroup$
    – Fred
    Feb 24 '19 at 16:29
  • $\begingroup$ @alephzero: thank you; yes, these will be 'light' objects up to 5kg; obviously, I would do the simulation first to find the dynamic response. At this point I am worried about the bolted connections. And yes, obviously [mm] :) $\endgroup$
    – filiply
    Feb 24 '19 at 17:27
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Most vibration fixtures are made of magnesium, at least they are for spacecraft launch vibration simulation.

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    $\begingroup$ Would you please edit and expand upon your answer, providing some references or examples? $\endgroup$
    – user16
    Feb 25 '19 at 13:17
  • $\begingroup$ This article about vibration tests also points that test fixtures are "often made of magnesium to help keep the weight down". $\endgroup$
    – jjmontes
    Aug 12 '19 at 17:24
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In addition to the replies you got on Eng-Tips site; at normal stress levels, steel has an unlimited fatigue life while the fatigue life of the aluminum will depend on the stress level and number of cycles. And the greater stiffness of welded steel may be an advantage.

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