Non-ordinary state-based peridynamic equivalent model for thick composite structures

In this study, a novel non-ordinary state-based peridynamic model is proposed for the assessment of strength and damage in thick composite structures. This framework homogenizes multi-layer laminated structures as generally anisotropic materials, with through-thickness mechanics represented by only three-layers of material points. The proposed model is distinct from existing peridynamic approaches in two key aspects: 1. This numerical framework is adept at characterizing the mechanical response of solid structures, thereby directly addressing a fundamental deficiency of classical plane-stress theory when applied to thick sections; 2. A novel stiffness degradation scheme is introduced, enabling the characterization of damaged composites via data exchange between an equivalent homogenized model and a planar problem, thereby bridging these two analytical scales. Furthermore, the proposed model achieves efficient simulation of laminated composites comprising numerous plies, which has historically been intractable for standard peridynamic methods due to prohibitive computational expense. The proposed framework demonstrates high numerical accuracy and solution efficiency in simulations, as benchmarked against a series of canonical problems, such as composite structures deformation and tensile tests of ASTM standard specimens. The damage progression in composite webs with various cutouts further demonstrates this PD model's potential in critical damage-phase mechanisms: damage identification and stiffness degradation.