Vibration Test Rig

[OwenU]

Hi everyone,

I am currently trying to put together a vibration test rig from a design and materials that were left over from a previous individual. I've attached the current design which is to be driven using a motor I've yet to acquire.

Essentially it is a four bar mechanism with a table and two pairs of rocker arms. I'm currently a bit confused about how this system would actually drive the table, as from the design I can't see how the table will correctly vibrate. I've had a look at some other designs which make more sense for this application such as a quick return mechanism, but the parts for the current design have already been fabricated.

The current design also calls for the rig to be driven by a washing machine motor, but I feel this will be a bit overkill as the design only calls for 9 kg loads to be tested.

If anyone has any ideas I'll be happy to hear them.

Thank you for reading.

 

[MintJulep]

It's not a design. It's a cartoon.
If the goal is to vibrate the table that this thing is set on then it should work fine. At least for a short time.

 

[EdStainless]

Sure, driving it with an eccentric crank will move it back and forth.
But what will the acceleration be and can you adjust it?
The motor bearings will take one heck of a load.
And I don't see any way to tune it (such as dampeners) other than changing motor speed.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[drawoh]

OwenU,

Read Vibration Analysis for Electronics Equipment, by Dave S. Steinberg. There is a section at the end on designing vibration fixtures.

--
JHG

 

[Tmoose]

"9 kg loads to be tested" - So the test item is 9 kg ?
Please describe the "vibration" the test item is to be subjected to.
Also the duration of the test.
Also the number of items to be tested at a time, and total batch size, etc, etc.

How is your quick return (slider crank) mechanism related to the parts in house?

Are there more detailed models of the hardware hiding within, or represented by, the "coupling guard" .


I think the test rig, as "designed" may experience fatigue failures at several locations a few times a week.

 

[btrueblood]

To Tmoose's excellent post, add:
what frequency range are you expecting to reach, and what amplitudes...or what spectra...

 

[btrueblood]

And, backing up a bit...what is the purpose of the vibration testing? Are you working to a specification or standard requirement?