signal intensity vs material thickness

[TKL8]

does anyone know what's the relationship between vibration signal transmissibility/intensity versus material thickness? Is there any literature regarding this subject?

the reason for this is that recently i have a bearing failure on a machine whereby the bearing housing is quite thick. the vibration level obtained was low. i suspect the thickness of the bearing housing could weaken the vibration signal, but i need literature to validate my finding.

Thanks

 

[GregLocock]

Depends on the 'mode' shape, and the frequency. If the bearing housing can be considered to be a simple cantilever, and no resonant effects are present, then the accelerations will be proportional to 1/thickness^3.

However, that is the very simplest case. These days most people would use an FEA model to work back to an excitation force, I suspect.

Cheers

Greg Locock