Fracture Toughness of Hybrid Hierarchical Honeycombs

Whiting, Ella (2021) Fracture Toughness of Hybrid Hierarchical Honeycombs. [USQ Project]

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The world of structural design and innovative materials is growing, and it is most engineers' goal to be on the cutting edge of innovation and design. Lattice structures are lightweight porous solid, that can be made in various shaped forms, such as triangular, hexagonal, square and kagome. Lattice structures are seen often in nature, and all man-made lattice structures mimic structures already existing. In-depth investigations have been completed on the fracture toughness an mechanical properties of non-hierarchical and self-similar lattice structures, particularly hexagonal structures. However, investigations have not yet extended into hybrid honeycomb structures which incorporate the desirable properties of both hexagonal lattices and triangular lattices into one structure. The investigation aimed to understand how to the topology of a structure and its relative density affected the fracture toughness of lattice structures. Three different topologies were incorporated into the design two hybrid structures combining the stretching-dominated properties of triangles and the bending-dominated properties of hexagons into one structure, and another lattice of self-similar triangular design. The structures were designed in Autodesk AutoCAD, and 3D printed using PLA filament. The lattices were tested for Mode 1 loading conditions, under tensile tests and four-point bending tests. This was undertaken as the experimental analysis. Then a numerical analysis was also undertaken utilising FEA simulations by ANSY R1 2021. From both analysis undertaken, the results maintained simliar for both the tensile and four-point bending structures. A bending-stretching dominated latticde structure, made up of hexagons, with the cell walls made from triangles is the best lattice structure as it both has low relative density and high fracture toughness. The self-similar triangular lattice and double layer hybrid hexagonal lattice both performed similar to each other. The relative densities increased significantly which also meat their fracture toughness reduced significantly. As a result a conclusion was drawn between the relative density and fracture toughness, that the increase in relative density, results in a decrease in fracture toughness for both self-similar and hybrid lattice structures.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Banerjee, Sourish
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 03 Jan 2023 05:37
Last Modified: 26 Jun 2023 03:24
Uncontrolled Keywords: lattice, hexagon, triangle, self-similar, density, fracture, hybrid lattice

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