Damping

[Pa.si]

I have a doubt concerning the damping, the damping factor is expressed in percentage or must be expressed in full. If for example you want a damping equal to 1% do I have to enter 1 or 0.01 in the settings? and by inserting damping proportional to the mass, is the mass parameter automatically defined by the software or should it be checked?

[huffte]

The damping is indeed % of critical and the parameters, whether mass or stiffness or Rayleigh damping is specified,are determined automatically in accordance with equations found in the help system. Should the user wish to over-ride the computed values, manual input is possible.

[ViraX]

I need to determine damping of a structure out of a free-vibration test that is already conducted and the time histories of acceleration are measured. Is any of the software here capable of estimating damping from the structural response? Thanks

[huffte]

The software does not have this capability, but it is a fairly simple hand calculation. Use the "logarithmc decrement" method, which may be found in most any textbook on structural dynamics, or from a web search on the term.