Mechanical properties improvement of shape memory polymers by designing the microstructure of multi-phase heterogeneous materials

[Display omitted] •Reinforcing SMPs by adding a third phase to the microstructure.•Enhancing mechanical properties of SMPs by designing the microstructure.•Reconstruction and homogenization of a multi-phase heterogeneous material.•Designing anisotropic microstructures with preference orientation for anisotropic SMPs.•Finite element analysis of SMPs using thermo-visco-hyperelastic approach. Nowadays smart materials are remarkably used to fabricate novel devices and modify the old ones. In this field, shape memory polymers (SMPs) regarding to their exclusive potentials are one of the most inclusive representatives. Generally, the SMP consists of two phases: the frozen phase (glassy state) and the active phase (rubbery state). The distribution, dispersion and preferential orientation of each phase could effectively influence on the thermomechanical response of the SMPs. Besides the advantages of SMPs, these materials are involved with some adverse issues, such as low recovered force range, uncontrollable recovery speed, and high working temperature, so that these issues may limit their utilization in some applications. In this paper, a novel approach based on a micromechanical blend of two different components is interestingly proposed to solve the aforementioned issues, modify and enhance the SMPs properties. To this end, several 3D realized representative volume elements (RVEs) with various volume fractions (VFs) and isotropic/anisotropic distribution of the second phase (non-matrix phase) have been generated using an in-house developed software. Then, employing a thermo-visco-hyperelastic model, the behavior of RVEs has been examined in various conditions, and through this not only the effective parameters (e.g., VF and orientation of second phase, value of applied pre-strain) have been recognized, but also the effect of each parameter on the SMPs behavior has been discussed. As reported in this research, by recognizing the efficient parameters through the proposed method, the mechanical enhancement and tuning of this class of smart materials is absolutely accessible and even anisotropic SMPs can come to existence.