Example of using notching to suppress vibration 3

[test123123]

In random vibration, notching is applied for various reasons such as excessive reaction forces or stress.

In real-world, what methods are used to implement this notching?

For example, is the PSD data received from external sources, such as road vibrations in a car or vibrations from external airflows in a helicopter, reduced using piezoelectric sensors or something?

 

[rb1957]

in airplanes we use "tuned vibration dampers" to reduce vibration perceived by the passengers (particularly in turbo-props).

I look at your graph and see the structure "stiffening up" at certain frequencies (and so reducing the vibration amplitude. I would think this is "just" different mode shapes within the structure, and this is affected by how the various structural elements are placed. I don't think satellites can afford the mass penalty of TVDs.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[btrueblood]

We had some rocket thrusters that had excessive stresses at certain frequencies during qual testing. We added some silicone rubber damping material (Lord Corp., now part of Parker Hannifin) at the bolt joint that knocked the levels down to an acceptable level. It's also possible to ask the vehicle manufacturer for relief - the spec. vibration levels are typically an envelope, but the true levels may be lower, especially at the point where your device is being bolted on.

 

[BrianE22]

I think you want a notch filter. Piezos are generally good at high frequencies (high output) and not so good at low frequencies (low output). I don't think you want to build a notch filter with them.

Are you looking to filter a "drive signal" for a test rig? When I did this kind of stuff we'd build a digital filter with the notches and pass the time history through it. The drive file then would not contain much content in the notched bands.