Innovative strategy for determining the spatial decoupling high-precision artificial boundary range under soil structure interaction

Reasonable determination of high-precision artificial boundary range in soil-structure interaction (SSI) is a critical step for accurately simulating radiation damping condition. Typically, outgoing scattering waves are dissipated by locating the boundary as far from near-field domain as possible. However, the large-scale SSI power response are limited due to the spatiotemporal coupling characteristics, especially the lack of a strategy to quantitatively assess the artificial boundary spatial coupling state. To this end, this study proposes a novel strategy for evaluating the spatial coupling in terms of the mean coupling degree using the relative gain array (RGA), which realizes the automatic determination for artificial boundary spatial decoupling range. The correctness and applicability are verified using the thin layer method (TLM) and the scaled boundary finite element method (SBFEM). Moreover, the artificial boundary spatial decoupling range applicable to the nuclear power structure-soil interaction is discussed, and the feasibility of the spatial partitioning decoupling method for the far-field dynamic stiffness matrix is investigated. The results show that the adopted decoupling method significantly reduces the storage cost while maintaining the calculation accuracy.