A finite deformation constitutive model for shape memory polymers based on Hencky strain

作者：Baghani M; Arghavani J; Naghdabadi R^*

来源：Mechanics of Materials, 2014, 73: 1-10.

DOI：10.1016/j.mechmat.2013.11.011

• Shape memory polymer
• Finite deformation
• Hencky strain tensor
• Continuum thermodynamics
• Finite element

In many engineering applications, shape memory polymers (SMPs) usually undergo arbitrary thermomechanical loadings at finite deformation. Thus, development of 3D constitutive models for SMPs within the finite deformation regime has attracted a great deal of interest. In this paper, based on the classical framework of thermodynamics of irreversible processes, employing the logarithmic (or Hencky) strain as a more physical measure of strain, a 3D large-strain macromechanical model is presented. In the constitutive model development, we adopt a multiplicative decomposition of the deformation gradient into elastic and stored parts. In addition, employing the averaging scheme, the logarithmic elastic strain tensor is decomposed into the rubbery and glassy parts. The evolution equations for internal variables are introduced for both cooling and heating processes. The time-discrete form of the proposed model in the implicit form is also presented. Comparing the predicted results with experimental data reported in the literature, the model is validated. Finally, using the finite element method, two boundary value problems e.g., a 3D beam and a medical stent made of SMPs are numerically simulated.

• 出版日期2014-6