Gradient Chain Structure Model for Characterizing Frequency Dependence of Viscoelastic Materials

Abstract

The frequency dependence modeling of viscoelastic (VE) materials faces the challenge of high modeling accuracy over a wide frequency range and double-objective optimization in model parameter identification. To address these two issues, a gradient chain structure model and a model parameter identification method are proposed. Inspired by chain structure models, two gradient functions are introduced to update the roles of a chain network and free chains in the mechanical behavior of VE materials. A two-step parameter identification method is proposed to obtain the model parameters and gradient functions. Then a dynamic property test of VE dampers is conducted to study the frequency effect on the equivalent stiffness and loss factor. Also, the test results are used to verify the proposed gradient model. Further, a comparison of the gradient model, a 5-parameter rheological model, the fractional derivative Zener model, and 10 sets of experimental data are conducted to illustrate the feasibility and superiority of the proposed gradient model for VE materials with different kinds of properties. The numerical data from the gradient chain structure model fit well with the experimental data over a wide frequency range, and the proposed model performs much better than the other two typical models in terms of both modeling accuracy and stability.