Inverse identification of the frequency-dependent mechanical parameters of viscoelastic materials based on the measured FRFs

- Both the material damping and the remaining equivalent viscous damping were considered in the analysis model.
- Storage modulus and loss factor were obtained simultaneously.
- Reasonable initial values of the viscoelastic material parameters were introduced into the identification process.
- Cantilever plate-shaped specimen was chosen to carry out the identification.

The mechanical parameters of viscoelastic materials, such as storage modulus and loss factor, have frequency-dependent characteristic and the combination of different polymers usually exhibits various mechanical characteristics, which make the identification of the mechanical parameters of viscoelastic materials become a routine and challenging task. In this study, based on the measured resonance frequencies and frequency response functions (FRFs) of a viscoelastic damping plate, an inverse approach was developed to identify the aforementioned parameters with frequency-dependent characteristic. An analysis model was established with both the viscoelastic material damping and the remaining equivalent viscous damping considered. A response surface method was provided to achieve the matching calculation, which can identify the storage modulus and loss factor simultaneously. A cantilever plate attached with ZN_1 viscoelastic material was chosen to demonstrate the proposed method and the measured and the predicted FRFs were compared with the purpose of assessing the rationality of identification results. The results show that the loss factor of viscoelastic materials would be overestimated if only the material damping was included in the analysis model.