Enhanced Mechanical Performance of Bio-Inspired Hybrid Structures Utilising Topological Interlocking Geometry

Abstract

Structural composites inspired by nacre have emerged as prime exemplars for guiding materials design of fracture-resistant, rigid hybrid materials. The intricate microstructure of nacre, which combines a hard majority phase with a small fraction of a soft phase, achieves superior mechanical properties compared to its constituents and has generated much interest. However, replicating the hierarchical microstructure of nacre is very challenging, not to mention improving it. In this article, we propose to alter the geometry of the hard building blocks by introducing the concept of topological interlocking. This design principle has previously been shown to provide an inherently brittle material with a remarkable flexural compliance. We now demonstrate that by combining the basic architecture of nacre with topological interlocking of discrete hard building blocks, hybrid materials of a new type can be produced. By adding a soft phase at the interfaces between topologically interlocked blocks in a single-build additive manufacturing process, further improvement of mechanical properties is achieved. The design of these fabricated hybrid structures has been guided by computational work elucidating the effect of various geometries. To our knowledge, this is the first reported study that combines the advantages of nacre-inspired structures with the benefits of topological interlocking.

Designing tough isotropic structural composite using computation, 3D printing and testing

“…Despite the presence of mechanically isotropic natural materials and the need for constructing composites with better isotropic responses [18,26], relatively less attention has been paid to the design of mechanically isotropic composites. Most existing studies have mainly focused on understanding and strengthening the mechanical properties in specific directions with additional toughening mechanisms, such as mineral bridges and wavy interlocking shaped platelets in the out-of-plane direction [27,28]. The effect of inclusion aspect ratio has been investigated in studies considering osteon-like composites [23,24], albeit the primary focus was not on the design of isotropic composites.…”

Automated 3D assembly of periodic alumina‐epoxy composite structures

“…Pull‐out effects are the most promising crack deflection mechanisms based on the high‐energy dissipation, leading to an improved toughness and crack resistance . Caused by the individual periodic arrangement in the monoclinic and triclinic arrangements, the crack propagation is axially hindered by topological interlocking of the brick‐and‐mortar like assembly . Thus cracks can only propagate by changing of the growth direction, which leads to a prolonged crack path shown in Figure and increased work‐of‐fractures in Table .…”

“…[10][11][12]18 Caused by the individual periodic arrangement in the monoclinic and triclinic arrangements, the crack propagation is axially hindered by topological interlocking of the brick-and-mortar like assembly. 9,28 Thus cracks can only propagate by changing of the growth direction, which leads to a prolonged crack path shown in Figure 9 and increased work-of-fractures in Table 2. For the cubic structures the comparable lowest work-of-fracture was determined as 523.3 AE 140.9 J/m², because of the unhindered crack propagation through the epoxy resin.…”

Computational Homogenization of Architectured Materials

“…with different objectives. For instance, developing architectured porous materials for structural, acoustic and insulation properties [40,70], entangled monofilament of pearlitic steel [47,173], sandwich composite structures [118,[163][164][165], segmented interlocking structures [59,60,62,65,66,72,117,123,136,[145][146][147]189], asymmetric frictional materials [18,19], woven and non-woven textile composites [57,130,141], porous metallic glasses [187], hierarchical composites [92], crumpled metallic foils [34]. Much more examples can be found in the present book.…”