Experiments with "Constrained Layer Damping" of Small Bore Connections

[yamoffathoo]

A British Firm (GL Industrial Services UK Ltd.) was experimenting with composites to dampen the dynamic response of small bore connections to compressors with the handle "Constrained Layer Damping".
This investigation was completed in 2019, but the Final Summary Report is a little sparce on details, claiming 50% reduction in dynamic stress levels.
Is there anyone out there doing similar work ?

 

[GregLocock]

CLD is widely used in automotive. One example is on brake pads. To reduce squeal a layer of black goo (bitumen possibly) goes on the back of the pad with a steel shim over it.

I'd estimate 90% reduction in noise. The sandwich construction is necessary to develop shear in the goo.

 

[dtimberlake]

Do you have a project, or is this just curiosity?

I think any torsionally flexible coupling would "reduce dynamic stress levels", no damping required.
Unless a torsional resonance is involved, and then a big whiff or two of damping would be desirable.

 

[yamoffathoo]

This post is an extension of my project to dampen the dynamic response of a 1/2"dia stainless steel tube x 40" span in a clamped-pinned configuration that fails in fatigue after 2 years operation.
So far the composite manufacturers I have contacted don't determine damping coefficients for their products.
The research literature indicates that a single layer of well bonded carbon based epoxy can reduce vibration levels by 50%.

 

[GregLocock]

That's not CLD. Badly bonding it might increase the damping.

 

[Tmoose]

" 1/2"dia stainless steel tube x 40" span in a clamped-pinned configuration that fails in fatigue after 2 years operation. "

Got pictures of the failure ?
What is the tube being asked to do for 2 years ?