Finite element modeling and experimental validation of brick-and-mortar structures with mesoscale interlocking interfaces

Bioinspired composite materials, such as nacre, achieve exceptional mechanical performance through the strategic arrangement of stiff and soft components. Inspired by this natural architecture, this study presents a novel finite element modeling framework for simulating staggered composites with finite-thickness interfaces. Combining continuum and cohesive elements, the model accurately captures tension-compression asymmetry and interface degradation, as validated by mechanical characterization of a mechanical interlocking fastener under tension, compression, and shear loading. The methodology was applied to staggered brick-and-mortar structures, with numerical simulations replicating 3-point bending experiments and achieving less than 3 % deviation in predictions of maximum load and displacement. A comprehensive parametric analysis identified key design parameters, including interface tensile strength, brick length-to-thickness ratio, and overlap, that govern structural performance. Additionally, the framework was extended to incorporate potential-based cohesive elements for modeling non-linear interface behavior, as demonstrated with hook-and-loop fasteners. Experimental validation revealed that hook-and-loop interfaces significantly enhanced energy dissipation, increasing from 189 mJ to 508 mJ compared to mushroom fastener interfaces. These findings underscore the versatility of the proposed modeling approach in predicting real-world behavior and optimizing composite architectures. This work provides a robust tool for the design of bioinspired materials with tailored mechanical properties, suitable for applications requiring energy absorption, durability, and strength.