don't forget that in this kinda test it all depends on frequency (if it's low - no worries), when you mount your UUT directly to the shaker table, there is some damping occurs(which is gonna depend on coupled diameters and tipe of mounting... I assume you used greese). Funny you should mention...
hm... Is there any way to calculate it from stard characteristic of the material? I'm interested in the same question, but I need to choose a material. The structure is known, as well as conditions and damping ratio. So, how do I choose the material if I know the damping ratio I need as well as...
