Tunable interface hardening: Designing tough bio-inspired composites through 3D printing, testing, and computational validation

In light of the demand for mechanically robust synthetic composites, researchers have adapted several toughening mechanisms of nacre, hardening through tablet sliding in particular has been in highlight till date. A few pioneers have reported an exclusive hardening phenomenon capable of amplifying the strength and toughness of staggered composites, however, works devoted to the tunability are limited to computation. Here, by employing design optimization, 3D-printing, and simulation, we demonstrate the evolution, and tunability of such deformation behavior. We discern two fracture mechanisms, columnar and non-columnar fractures, which elucidate hardening and toughening observed for interlocking and non-interlocking tablet topologies. Computation analyses at various fracture stages are conducted to unravel the change in stress concentrations, comprehending the fracture mechanisms in depth. We present vital insights on the multi-stage deformation behavior and its tunability in staggered composites, which currently has reached the pinnacle of interest for developing composites with superior mechanical properties. ? 2021 Elsevier Ltd