Bending of a polyurethane based shape memory polymer: modeling and experiment

  • Author / Creator
    Ma, Xiaoang
  • Shape memory polymers (SMPs) can be used in many critical applications, including biomedical and aerospace fields, due to their ability to recover their original/permanent shape from a deformed/temporary shape upon application of a stimulus. SMPs are subjected to bending in a large number of these applications, e.g. morphing aircraft components or biomedical stents; however, predictive models used for bending are very limited in the literature. Consequently, there is a need to build a bending model for SMPs, and this thesis addresses this gap in the literature. A rheological model previously developed by Tobushi for uniaxial loading was extended to bending and implemented numerically to calculate the time-dependent deflection of a thin beam. Corresponding experiments for a polyurethane based shape memory polymer were conducted to verify the model. Creep tests were conducted to extract the values of parameters required for the rheological model. Extrusion based additive manufacturing (EBAM) technique was used to produce the specimens used in experimental tests. Results indicate that the rheological model is able to describe the material behavior well over a certain range of temperature while the discrepancy between experiment and model becomes significant if the temperature deviates from this range. Through this study, the manufacturing, modeling and related mechanical characterization of the shape memory polyurethane were investigated and these findings can be used for further studies and design of SMPs.

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  • Graduation date
  • Type of Item
  • Degree
    Master of Science
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    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.