A multiscale mechanical model of superconducting multilevel sub-cables based on asymptotic homogenization method

As a critical component of the International Thermonuclear Experimental Reactor (ITER), the complex stress state of superconducting wires within Cable-in-Conduit Conductors (CICC) significantly impacts overall system performance. To address the high computational and economic costs associated with traditional numerical simulations and experiments, a multiscale numerical model is developed based on the asymptotic homogenization method (AHM) to study the macro global mechanical responses and micro stress states of CICC sub-cables. The numerical model incorporates macroscopic modeling while retaining the microscopic information from superconducting wires. Macroscopic strain data from the sub-cable are input into a representative volume element (RVE) to obtain the true microscopic stress distribution. The AHM framework's accuracy is validated by comparing the global mechanical responses, local contact forces, and micro stress distributions of sub-cables with results from direct numerical simulations (DNS), experiments and theoretical analysis. Compared to DNS, AHM-based numerical modeling reduces computational time cost by an order of magnitude while ensuring the validity of the calculation results. Furthermore, the axial load bearing capacity and lateral contact force of three representative superconducting sub-cables are evaluated, revealing that adjusting structural parameters of sub-cables can improve local contact forces while keeping von Mises stress of filament bundles change slightly, which enhances the global load-bearing and local contact performance. This work provides a valuable framework for efficient multiscale numerical modeling of CICC multilevel sub-cables containing thousands of composite wires.