Abstract
Shape memory polymers (SMPs) are a class of soft active materials that have the ability to retain one or multiple temporary shapes and exhibit deformation as a response to stimuli. The temporary shapes involved can be very complex but SMPs can recover large amounts of strains as compared to other smart materials. They have a wide range of applications in fields as diverse as healthcare, transportation, energy generation, etc. and their mechanism can be easily altered. Hence, there is an increasing need to model their behavior. This paper discusses the behavior of a thermally activated subclass of SMPs in which the temporary shape is fixed by a crystalline phase and the return to original shape is due to the transition of this crystalline phase. We simulate its thermo-mechanical behavior using a framework based on the theory of multiple natural configurations. Viscoelastic effects have been incorporated using a rate type model along with the anisotropy of the crystalline phase. The model has been applied to boundary value problems of homogeneous deformations such as uniaxial extension of dual shape and triple shape memory polymers under controlled stress and strain conditions. The model has also been applied to boundary value problems related to inhomogeneous deformations such as circular shear, inflation, and extension of a hollow cylinder. The effects of parameters such as temperature, external stress, crystallinity, shear modulus and relaxation time on the nonlinear deformation have been studied. The results are found to be consistent with the experimental data and show how the complicated thermo-mechanical behavior and shape memory effect are influenced by these parameters.
Original language | English (US) |
---|---|
Article number | 103524 |
Journal | International Journal of Engineering Science |
Volume | 167 |
DOIs | |
State | Published - Oct 1 2021 |
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- General Engineering
- Mechanical Engineering
- General Materials Science
Keywords
- Crystallization
- Multiple natural configurations
- Shape memory polymer
- Thermo-mechanical model
- Triple shape memory effect
- Viscoelasticity