Damping ratio of hybrid structure

[TOKYOTech]

Dear all,
I want to build a wood-concrete hybrid structure, and I'm confused about the setting of damping ratio. Should I input a single damping ratio and calculate the RayLeigh damping or should I set different damping ratio for the wood part and the concrete part? And if the later one, how to achieve it?
Thank you

[fmk]

not sure of what you are trying to model .. codes will give you damping ratios for structures that are either concrete or wood but not combined .. given sources of damping, e.g. concrete cracking .. if you want to use different ratios use the region command to specify different damping values for different regions of the model.

[TOKYOTech]

Thank you very much! The region command should solve my problem to define different damping ratios in different parts.