Mesomechanical modeling of debonding failures in FRP-strengthened structures

Debonding mechanisms in FRP-strengthened structures have been the subject of numerous investigations. Most of the modeling studies conducted thus far are based on the assumption of macroscopic relationships between local interfacial stresses and local relative displacements between FRP and substrate. Such laws are calibrated experimentally and incorporated in structural models with the purpose of determining macroscopic quantities of design interest. This approach presents a number of limitations, as macroscopic interfacial laws spatially homogenize complex damage and failure processes taking place at the lower scales. This paper proposes an alternative approach to the problem of FRP debonding, based on a mesomechanical analysis including explicit description of the interfacial geometry, and illustrates the first steps taken by the authors in this direction. The final goal is to be able to design and optimize the macroscopic interfacial behavior by tailoring the features at the lower scale. Also, a deeper understanding of mixed-mode interfacial failures is aimed at. The paper illustrates the basic idea, the main details about the current implementation, and preliminary numerical results.