Establishment of constitutive model based on Ogden strain energy storage function and its matching with the mechanical properties of polyurethane dielectrics

Abstract

In order to find the constitutive relationship of mechanical properties suitable for polyurethane dielectric elastomer, the constitutive model of dielectric elastomer based on Ogden strain energy storage function was established. Then taking polyether MDI polyurethane as the research object, the first-order, second-order and third-order Ogden constitutive models were fitted by the preparation and mechanical properties test of polyurethane dielectric elastomer with different soft and hard segment contents. It is found that the second-order Ogden constitutive model fits the stress-strain curve of polyurethane dielectric elastomer well, and the highest modified fitting coefficient is as high as 0.9996. At the same time, we found that the fitting effect of the third-order Ogden constitutive model is greatly affected by the soft segment content, and the fitting effect is good when the soft segment content is high, while the fitting effect of the first-order Ogden model is bad. In addition, there is no effect when the drawing rate and shape change. This is because the first-order Ogden model can be simplified into Neo Hooken model and Mooney Rivlin model, which are suitable for the mechanical behavior of small deformation range and have poor fitting for the nonlinear large deformation process of the system.