Composite modal damping

[bkal]

I hope this forum can help me to understand physical background / interpretation of this option to model damping in Abaqus/Standard:

I tried to search the manuals for explanation of how is this implemented and how (or even if) to use this in practical applications for modelling civil structures.

 

[FEA way]

This is described in the documentation chapter "About dynamic analysis procedures" (paragraph "Damping in dynamic analysis"). In short words, it assigns a critical damping fraction to each mode based on critical damping fractions that were assigned (by the user) to material definitions or selected elements. It can be useful when there are many materials with significantly different damping characteristics.

 

[GregLocock]

In linear analysis the assumption is that each mode is a global property and so damping of the mode is global as well. It kinda sorta works like that in practice (experimental modal analysis) but is one of the causes of reciprocity failure.

Cheers

Greg Locock


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