Method for the identification of constitutive model parameters of high damping viscoelastic materials

Viscoelastic materials are widely used in several technological areas for reducing and controlling the structural vibrations and noise radiation. The numerical analysis and design of structural systems involving viscoelastic damping materials require knowledge of material properties and proper mathematical models. The elastic and dissipative properties of viscoelastic materials can be characterized by the forced vibration test with resonance stated by the standard ASTM E765-05. Nevertheless, the described material parameter extraction procedure fails to correctly determine the dynamic properties of high damping and strong frequency-dependent viscoelastic materials. Therefore, a new inverse method for the dynamic characterization of high damping and strong frequency-dependent viscoelastic materials is presented. The proposed inverse method minimizes the residue between the experimental and theoretical dynamic response of cantilever beams at certain discrete frequencies selected by the user in order to identify the parameters of the considered material constitutive model. Thus, the material properties are identified in the whole bandwidth under analysis and not just at resonances. Moreover, the use of control frequencies makes the method insensitive to experimental noise and the efficiency is notably enhanced. Therefore, the number of tests required is drastically reduced and the overall process is carried out faster and more accurately than with the method proposed by the standard ASTM E756-05. The effectiveness of the proposed method is demonstrated with the characterization of a thin viscoelastic film in CLD (constrained layer damping) configuration, where the identified viscoelastic properties are validated correlating the experimental and numerical dynamic response of several response DOFs of the tested CLD cantilever beam.