عنوان مقاله [English]
Shape memory polymers are a class of multi-phase smart materials which have the ability to return from a deformed state (temporary or fixed shape) to their original (or permanent) shape, called as shape memory effect, (or recovery) under different thermo mechanical cycles, e.g., fixed strain stress recovery and fixed stress strain recovery. Due to their unique behavior, shape memory polymers have many applications in industry areas. Shape memory polymers have been researched, developed, and utilized in a wide range of applications such as advanced technologies in the aerospace, medical and oil exploration industries. Moreover, shape memory polymers have a promising future for application in sensors, actuators and smart devices. However, applications of shape memory polymers are restricted by their low strength. Different techniques are employed to eliminate such restrictions. Among them, addition of micro and/or nano-particles is a common practice. In this study, a numerical method, based on 3D finite element method, is introduced to investigate the effect of nano-particles on mechanical properties (e.g., the mechanical strength) and performance of shape memory polymer nano-composites. The non-linear behavior of shape memory polymers is described through employing a recently proposed visco-hyper-elastic constitutive model, and the nano-composite is simulated in the framework of the nonlinear finite element method. Effects of different volume fractions and aspect ratios of the nano-particles are investigated, and the results are presented in the form of stress strain temperature diagrams. According to the produced results, increasing the volume fraction and/or aspect ratio increases the generated elastic stress and the recovered stress. In addition, adding up to 3 percent of nano-particle volume fraction and applying strains up to 20 percent would not disrupt the performance of the material, while remarkably enforce the shape memory polymer based nano-composite.