Explicit Complex-Valued Damping
In frequency domain, it is possible to define damping by modeling the dissipative behavior of the material using complex-valued material properties. In COMSOL Multiphysics, you can enter the complex-valued data directly, using i or sqrt(-1) for the imaginary unit.
However, entering complex-valued data directly into the material parameters is incompatible with the built-in damping and viscoelasticity features.