A simple phenomenological model for recovery behaviors of amorphous thermoset‐based shape memory polymers via a time‐varying viscosity

Abstract

AbstractShape memory polymers are a typical class of smart materials with wide potential applications. Mathematically modeling their thermomechanical behaviors with both simplicity and accuracy is challenging. In this work, a time‐varying viscosity model was introduced to investigate amorphous thermoset‐based shape memory polymers, with a special focus on recovery behaviors. This model employs only a varying viscosity to describe both the mechanism of strain storage and release during the shape memory cycle and the modulus‐temperature trend, along with a phenomenological description for the structural transition. Furthermore, the model effectively captures the effect of temperature rates and load conditions on recovery behaviors by tracking the evolution of parameter τ. This parameter shares the same dimension as time and serves as a phenomenological indicator of the chain mobility. Moreover, the parameter τ exhibits similar values among diverse materials at a specific characteristic temperature, providing a simple way to estimate the extent of recovery.Highlights Introduced a simple phenomenological model to reproduce recovery behaviors and depict the modulus‐temperature trend. Both simulation and prediction results exhibit good agreement with tests. Effects of heating rates and load conditions can be traced by the model. The key model parameter τ possesses engineering and physical significance.