Shape memory polymers (SMPs) are a class of smart materials which can undergo transition between two different states (temporary shape and permanent state) induced by external stimuli, such as temperature, light etc. In order to study the deformation behavior of this fast-developing SMP structures, the key points are formulating suitable theoretical constitutive models to correctly reflect the material behavior and developing appropriate numerical simulation techniques to handle complex structures. In this paper, we proposed a three-dimensional (3D) thermomechanical constitutive model of SMPs and its implementation as a user material subroutine, UMAT, in a finite element package ABAQUS. The shape memory effects of the SMPs under three different loading patterns are simulated by the proposed approach and the acquired numerical results are compared with theoretical computational results and available experimental data. They agree reasonably well. Two SMP structural examples are presented to demonstrate the feasibility of the proposed approach. The exercises involve the analyses of (i) an intelligent hexachiral deployable structure and (ii) a 3D self-folding structure achieved through a 2D plate.

形状记忆聚合物（SMP）是一类智能材料，可以在外部刺激（例如温度，光等）引起的两个不同状态（临时形状和永久状态）之间进行转换。为了研究这种快速变形的变形行为，在开发SMP结构时，重点是制定适当的理论本构模型以正确反映材料的行为，并开发适当的数值模拟技术来处理复杂的结构。在本文中，我们提出了SMP的三维（3D）热机械本构模型，并将其作为用户材料子例程UMAT实施在有限元程序包ABAQUS中。通过该方法模拟了SMP在三种不同加载模式下的形状记忆效应，并将获得的数值结果与理论计算结果和可用的实验数据进行了比较。他们同意得很好。给出了两个SMP结构示例，以证明该方法的可行性。练习涉及（i）智能六手性可展开结构和（ii）通过2D板实现的3D自折叠结构的分析。