Bolting for Low Vibration Application

The problem is which will be the compliance of the bolted/welded connection. If the compliance is such that with the masses on it the fixture will reach one of the test frequencies then the results will not be any more correct.

The own frequencies of the supported mass + fixture MUST be way over the highest test frequency= at least x4...5.

Thsi is valid also for the way the fixture is bolted on the vibrating table. Those simple aspects were not always respected with very unpleasant results.

I agree with Nick.

If the vibration levels were of fairly low 'g', then maybe you could use high quality bolts that were installed with a torque wrench and had a drop of a lock-tite material applied on the sides of the heads to prevent rotation.

But I'd think you'd only do this if you needed to dis-assemble the mounting fixture afterward. Otherwise it would be less trouble to just weld, and it would be more rigid.

"Applied with a torque wrench"

This is a typical comment made in the context of bolted joint integrity. Unfortunately, it's ignorant, misleading and, sometimes even dangerous

It's bolt preload that we're after. It's not torque!! Torque is just a measurement of resistance. One cannot confidently predict that a certain "torque" will result in a certain bolt preload. As a result, your assembly may fail even though you "applied the proper torque".

Here's an interesting link:

The Dangerous Misconception of Torque

Do you think that a calibrated torque wrench may help? Think again.