Full scale analysis of FRP strengthened plates with irregular layouts

The analysis of plates, slabs, or walls, strengthened with fiber reinforced polymer (FRP) composite materials, presents multi-faceted analytical, modeling, and computational challenges. Current analysis tools, including 3D and 2D analyses, still face the challenge of handling full scale, realistic, and geometrically irregular FRP strengthened plate-like structures. Consequently, the understanding of the intricate behavior of this increasingly prevalent structural form is far from being complete. Specifically, the ability to locate and quantify stress concentrations along geometrically irregular FRP edges and contours of existing delaminated regions is not fully developed. This paper presents a specially tailored, multi-layered, high-order plate model, and a corresponding triangular finite element, which aims at meeting the modeling and computational challenges. The formulation mitigates shear locking through augmentation of the shear-bending decomposition and its generalization to the case of high-order, multi-layered configuration. It thus enables analyzing FRP strengthened plate-like structures of general geometry, layout, strengthening scheme, and existing, irregular delaminations. The latter feature is realized by introducing an interface modeling which handles different bond/delamination interfacial conditions in a unified approach. The present work helps shedding new light on the complex and irregular stress concentrations that govern the principle failure mechanisms of this multi-layered structural form.