Constitutive modeling of the mechanics associated

Authors: G Barot I J Rao

Publish Date: 2006/03/17

Volume: 57, Issue: 4, Pages: 652-681

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Abstract

Shape memory polymers are novel materials that can be easily formed into complex shapes retaining memory of their original shape even after undergoing large deformations The temporary shape is stable and return to the original shape is triggered by a suitable mechanism such as heating In this paper we develop constitutive equations to model the mechanical behavior of crystallizable shape memory polymers Crystallizable shape memory polymers are called crystallizable because the temporary shape is fixed by a crystalline phase while return to the original shape is due to the melting of this crystalline phase The modeling is done using a framework that was developed recently for studying crystallization in polymers 28 25 27 31 and is based on the theory of multiple natural configurations In this paper we formulate constitutive equations for the original amorphous phase and the semicrystalline phase that is formed after the onset of crystallization In addition we model the melting of the crystalline phase to capture the return of the polymer to its original shape The model has been used to simulate a typical uniaxial cycle of deformation the results of this simulation compare very well with experimental data In addition to this we also simulate circular shear of a hollow cylinder and present results for different cases in this geometry

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