Nonlinear Schapery viscoelastic material model for thermoplastic polymers

Understanding Rheology of Thermoplastic Polymers

1 AAN013 shear rate behavior. For example, gauge variation can be caused by variable post-extrusion die swell, and warpage can occur from non-uniform relaxation during cooling of an improperly formulated injection molding compound. Also, by testing at low enough shear rates so that the measurements are in the melt’s linear viscoelastic region, the data can be linked directly to the polymer’s mo...

A Discrete Complex Compliance Spectra Model of the Nonlinear Viscoelastic Creep and Recovery of Microcellular Polymers

The present work reports a discrete stress-dependent, complex compliance spectra method that may be used to predict the mechanical response of nonlinear viscoelastic polymers during creep and recovery processes. The method is based on the observation that the real and imaginary parts of a discrete complex compliance frequency spectra obtained from creep and recovery measurements are smooth, eas...

Mechanical Response of Beams of a Nonlinear Viscoelastic Material

A constitutive equation for nonlinear viscoelasticity is used to model the mechanical response of solid polymers such as polycarbonate. The nonlinearity arises from a reduced time which causes stress relaxation to accelerate with increasing strain. The constitutive equation can account for the occurrence of yield in a homogeneous uniaxial constant strain rate test. The constitutive equation is ...

Mechanical Behavior of Filled Thermoplastic Polymers

Comprehensive Material Characterization for Polymers