Nature-inspired orientation-dependent toughening mechanism for TPMS ceramic architectures

Abstract

Triply periodic minimal surfaces (TPMSs) have been extensively studied in many fields of engineering, including bone tissue scaffolds. Recent advancements in manufacturing have enabled the three-dimensional printing of ceramic porous architectures; however, their intrinsic brittleness limits its practical applications. It has been observed that the ossicles of the knobby starfish exhibit a mineralized TPMS structure with lattice distortions (i.e., dislocations), which effectively deviate the crack propagation and enhance the fracture energy. In this article, the aforementioned toughening mechanism has been introduced in a TPMS architecture. We employed finite element models to analyze the effective mechanical properties of the structures under compression, both in the elastic and post-elastic regimes. Our analysis reveals that the introduction of the dislocation induces variations in both elastic and fracture properties of the structures. With particular reference to the fracture behavior, a suitable oriented edge dislocation is able to alter the crack nucleation and propagation, resulting in a tougher structure. Both the elastic and fracture phenomena can be enhanced or reduced by changing the dislocation density.