On behaviors of porous shape memory polymer under different loading conditions

Shape memory polymer (SMP) has drawn much attention in the fields of aerospace, microsystems and biomedicine as a typical smart material with unique shape memory properties. The porous SMPs (P-SMPs) have been manufactured for the applications of reduce noise and insulate thermal. A constitutive model of P-SMPs that proposed based on phase transition theory has been investigated in this work. First, combining Mori–Tanaka method and phase transition theory, a modified micromechanics constitutive model of P-SMPs has been presented to describe the thermal-mechanical behavior of P-SMPs. Then, a series of experiments including uniaxial tension, stress relaxation and thermal cycling test have been conducted to determine the parameters of the modified constitutive model. Finally, the correctness of the proposed constitutive model has been verified by comparing the results of the thermodynamic cycle process including heating recovery and cooling loading stages obtained by the numerical simulation results and thermodynamic cycle experiment. The results show that with a porosity f = 0.1, the strain and stress mean square errors of the constitutive model based on the phase transition theory are 0.22 and 0.0102, respectively, which means that the constitutive model proposed based on phase transition theory can reflect the shape memory properties of P-SMP materials.