In this paper, in view of the discrete and multiscale characteristics of the cable-in-conduit conductors, a new bottom-up methodology for constructing a 3D model of multistage superconducting cable is proposed based on the discrete element method (DEM). On the basis of the discretization of the continuum and the improved cohesive bond model, a single-strand DEM model is first established. Furthermore, the spatially geometric configuration of the cable is generated stage by stage according to cylindrical spiral equations, and the contact force law is also introduced into the DEM model to characterize the interaction between the strands inside the cable. The established models are validated by means of macroscopic deformations of multistage cable under various external loadings. Under high transverse stress level, an elastic–plastic force law is tentatively introduced for characterizing plastic deformation of the strands at the contacts. Finally, the necessity of the incorporation of elastic–plastic force law into our DEM model of superconducting cable is further discussed. The proposed methodology presents a new way of constructing a multistage model from at strand even up to the full cable, and an additional potential advantage of the established model is to quantitatively investigate localized strains and nonuniform contacts inside the cable on a sub-cable level or even down to the level of a single strand.

在本文中，针对电缆套管导体的离散和多尺度特性，提出了一种基于离散元法（DEM）构建多级超导电缆3D模型的自下而上的新方法。在连续体离散化和改进的内聚键模型的基础上，首先建立了单链DEM模型。此外，根据圆柱螺旋方程逐步生成电缆的空间几何构型，并将接触力定律引入DEM模型来表征电缆内部各股线之间的相互作用。建立的模型通过多级电缆在各种外部载荷下的宏观变形进行验证。在高横向应力水平下，暂时引入弹塑性力定律来表征接触处股线的塑性变形。最后，进一步讨论了将弹塑性力定律纳入我们的超导电缆 DEM 模型的必要性。所提出的方法提出了一种构建从绞合线到整条电缆的多级模型的新方法，所建立模型的另一个潜在优势是在子电缆水平上定量研究电缆内部的局部应变和非均匀接触或甚至下降到单股的水平。