What is absolute and relative damping?
What is absolute and relative damping?
(OP)
Hi,
I was wondering what absolute and relative damping mean? I am looking into vibration testing methods - impact hammer testing can measure the absolute damping while shaker testing measures relative damping. Can anyone help with their definitions and possible application?
I was wondering what absolute and relative damping mean? I am looking into vibration testing methods - impact hammer testing can measure the absolute damping while shaker testing measures relative damping. Can anyone help with their definitions and possible application?





RE: What is absolute and relative damping?
Cheers
Greg Locock
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RE: What is absolute and relative damping?
RE: What is absolute and relative damping?
Do you have a definition for them?
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(2B)+(2B)' ?
RE: What is absolute and relative damping?
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(2B)+(2B)' ?
RE: What is absolute and relative damping?
A hammer test is absolute in the sense that the object is "fixed" at some point, or surface, and that "fixed" point experiences no disturbances, while the struck point experiences the hammer. A shaker table disturbs both points, and everything is relative to the control (formerly fixed) point. BUT, because the vibrating point is normalized to the control point, the system response is "absolute," since the results are as if the control point were "fixed"
TTFN

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RE: What is absolute and relative damping?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: What is absolute and relative damping?
relative damping is defined as a percentage of critical damping...with critical damping implicitly defined as that damping parameter that results in a critically damped response.
Yes, it all assumes a linear response regime.
Absolute damping is a coefficient that is related to a force that opposes motion. It can have various units depending on how you define it and can be dimensionless or dimensioned.
Relative damping is most commonly referred to as it is more easily identified and used.
RE: What is absolute and relative damping?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?