Single Integral Constitutive Equations for Viscoelastic Fluids

摘要

It is demonstrated how the kernel functions of single integral constitutive equations may be determined from analysis of experiments in time dependent shear-free flows alone. It is assumed that the kernel functions may be factored into a product of a linear viscoelastic function and a finite-strain dependent function. No assumption is needed on the strain-dependent function except that it must be continuous within the attainable invariant space. The experimental data for ever-increasing deformations are not compatible with the assumptions inherent in single integral constitutive equations with factorized kernel functions.