Volk, Brent L. (2009-05). Thermomechanical Characterization and Modeling of Shape Memory Polymers. Master's Thesis.
This work focuses on the thermomechanical characterization and constitutive
model calibration of shape memory polymers (SMPs). These polymers have the ability to recover seemingly permanent large deformations under the appropriate thermomechanical load path. In this work, a contribution is made to both existing experimental and modeling efforts. First, an experimental investigation is conducted
which subjects SMPs to a thermomechanical load path that includes varying the value
of applied deformations and temperature rates. Specifically, SMPs are deformed to
tensile extensions of 10% to 100% at temperature rates varying from 1 degree C /min to
5 degree C/min, and the complete shape recovery profile is captured. The results from this
experimental investigation show that the SMP in question can recover approximately
95% of the value of the applied deformation, independent of the temperature rate
during the test.
The data obtained in the experimental investigation are then used to calibrate,
in one-dimension, two constitutive models which have been developed to describe
and predict the material response of SMPs. The models include a model in terms of
general deformation gradients, thus making it capable of handling large deformations.
In addition, the data are used to calibrate a linearized version of the constitutive
model for small deformations. The material properties required for calibrating the
constitutive models are derived from portions of the experimental results, and the
model is then used to predict the shape memory effect for an SMP undergoing various levels of deformation. The model predictions are shown to match well with the