A viscous approach based on oscillatory eigensolutions for viscoelastically damped vibrating systems
Viscoelastic Vibrating Systems can be approximated by certain viscous approach named Equivalent Viscous Model (EVM). The EVM shares oscillatory (complex) modes with the original viscoelastic systems and neglect non-viscous (real) modes contribution. The EVM eigenvectors are those of the undamped problems, and these lead to a proportional system. EVM of real systems is in agreement with VEM in terms of the FRF, especially for proportional or lightly non-proportional damping.
equivalent viscous model viscoelastic systems complex eigenvalues complex eigenvectors proportional damping