Identification of viscoelastic material parameters based on DMA analysis results

The article addresses the problem of identifying parameters for viscoelastic material models made from closed-cell polyurethane foam based on results obtained using a dynamic mechanical analyzer (DMA). DMA testing allows determining viscoelastic characteristics of materials — complex elastic modulus over a wide frequency range. For engineering applications, the most important practical application is within the frequency range of 1–1000 Hz to solve problems related to dynamics (vibration isolation and seismic insulation), as well as acoustics (protection against structural sound transmission). In engineering practice, various phenomenological material models are used, ranging from Kelvin-Voigt (KV) model and standard linear solid (SLS) model up to fractional derivative-based models such as fractional KV model, fractional SLS model including those with multiple fractional parameters. Using DMA test results—dependencies of real and imaginary parts of elastic modulus versus frequency, these models' parameters are adjusted by means of least squares method. The accuracy of approximation along with identified model parameters specific to the chosen type of material are evaluated.