Identification of the parameters of the maxwell model using self-excited oscillation
The viscoelastic materials such as rubbers and plastics have the properties both of elasticity and viscosity. It is necessary to evaluate the viscoelastic materials quantitatively in industry. The viscoelastic materials are well-known to be represented using the Kelvin-Voigt model or the Maxwell model. In this study, we focus on the Maxwell model which has a viscous damper and a spring connected in series. The conventional measuring methods have the stress relaxation test and the dynamic mechanical analysis (DMA). The stress relaxation has the time dependency and the DMA is easily affected by the experimental environment. We proposed a new experimental method taking account of the experimental environment to identify the spring constant and the viscosity coefficient of the Maxwell model precisely. In measurements, we propose utilizing the self-excited oscillation by positive velocity feedback control. The parameters of the Maxwell model can be experimentally identified from the feedback gain and the frequency of the self-excited oscillation. Furthermore, the validity of the proposed method is experimentally tested using a prototype system.