Analysis of the coupled cascade failure model in complex networks with functional dependence

Cascade failure is a critical nonlinear fault propagation mechanism in complex networks. Expanding on the classic “load correlation” cascade failure model, this research introduces a novel functional dependency analysis model that quantitatively captures node dependency relationships. It also develops a coupled cascade failure model integrating load and dependency cascades. This model defines the correlations and transformations among nodes in terms of “load-capacity-efficiency-performance,” quantifies the effects of functional dependency on cascading failures, and offers a more precise representation of fault propagation in networks influenced by both dependency and load coupling. Simulations on single-layer network and interdependent networks examined efficiency, performance, and failure scales under intentional attacks and regional damage. Results reveal that coupled cascading significantly heightens network vulnerability, with dependency relationships lowering the network failure threshold compared to node failure trigger threshold. This model provides valuable guidance for improving network security and optimizing system parameters.