I'm running a vibrational analysis on a welded/bolted aluminum fixture. Trying to find some decent information online in regards to (modal) damping ratio for this type of fixture seems challenging. Solidworks has a few articles (here and here).

The first article states 0.1 for lightly damped systems; the second article states either <0.1 for metals (in elastic range), 0.2-0.4 for continuous metal structures or 0.3-0.7 for jointed metal structures. It also has a table below that gives 0.5E-04 for Aluminum.

Lots of conflicting data here, & I'm trying to be conservative in my analysis. I know that damping is relatively unknown & highly dependent on the system, but I'm a little nervous that using 0.1 as a global damping coefficient may not be conservative enough?

Any guidance would be appreciated.