本研究考虑了复合燃料中UN和U₃Si₂的弹性变形、辐照肿胀和蠕变变形，建立了三维本构关系、应力更新算法和一致刚度模量，编制了定义材料辐照力学本构关系的用户材料子程序UMAT，并根据复合燃料芯块的微观结构特征，选取代表性体元建立有限元模型，实现特定辐照条件下的复合燃料有限元模拟。

In this paper, the elastic deformation, radiation swelling and creep deformation of UN and U₃Si₂ in composite fuels are taken into account, and the three-dimensional constitutive relation, the stress updating algorithm and the uniform stiffness modulus are established, a user material subroutine, UMAT, was developed to define the constitutive relation of irradiation mechanics of materials, and a finite element model was established based on the microstructural characteristics of composite fuel pellets, the finite element simulation of composite fuel under specific irradiation conditions is realized.