Global stiffness for tonal excitations--any good?

[jeyaselvan]

I have observed that most of the structures (structures which responds to vibration & radiate noise) concerning NVH have very high global stiffness. I believe they are primarily intended to make the structure more stiffer by have lesser modal density. This effects in less modal responses thereby having lesser overall response to random excitations. But mostly in automotive applications, the excitations are of tonal nature. If so, how does does this really helps? I do believe they are not intended for tuning of the resonances away from the excitations.

 

[GregLocock]

You are right. There are many automotive applications where a less stiff structure is quieter.

Arbitrarily setting high stiffness targets is a waste of money.

For instance on a recent program we reduced the stiffness of the subframe by 70% and got a 1 dBA improvement in a noise of great interest.

Cheers

Greg Locock

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