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Failure Modes and Fracture-Path Reproducibility in 2D Honeycomb and Diamond Sandwich Architected Cores Under Quasi-Static Loading
Subject area: Science,Engineering and Technology · Area of research: Mechanical
Abstract
Architected sandwich cores are widely adopted for their stiffness-to-weight efficiency, yet the literature remains weighted toward stiffness and energy-absorption metrics, with comparatively little systematic data on how such cores actually fracture. This study reports a controlled experimental investigation of failure modes, load-response classification, and fracture-path reproducibility in two-dimensional honeycomb and diamond sandwich cores under quasi-static loading. Eight core configurations were examined: honeycomb at unit-cell angles of 15°, 30° and 45°, diamond at 45°, 90° and 120°, and a functionally graded variant of each topology in which vertical cell height was graded through the core thickness. All specimens were additively manufactured from a UV-cured brittle photopolymer resin, deliberately selected so that fracture rather than plastic collapse would govern, and tested in five replicates per configuration under three-point bending and uniform quasi-static compression. Full-field deformation was recorded by two-dimensional digital image correlation. Core shear governed failure in every honeycomb configuration under both loading modes, whereas the diamond topology exhibited a mode transition with cell angle: buckling dominated at 45° and 90°, while the 120° and functionally graded configurations deformed in a bending-dominated manner with minimal fracture. Load responses conformed to Type II behaviour for the honeycomb and lower-angle diamond cores, with the 15° honeycomb exhibiting a partial Type II response, and to Type I behaviour for the 120° and functionally graded diamond cores. Fracture paths were reproducible in a well-defined subset of configurations, recurring as 180° straight and 120° oblique propagation lines, while the remaining configurations showed no repeatable path. This division is attributed to the interaction between loading-nose position and core strut placement in specimens without enforced core symmetry. The functionally graded cores concentrated deformation within targeted compliant regions while leaving stiffer regions intact, demonstrating spatially programmable failure. The resulting failure-mode map and reproducibility classification provide a quantitative reference dataset for validating numerical models of architected core fracture.
Keywords
architected materials; sandwich structures; honeycomb; diamond lattice; failure modes; fracture reproducibility; functionally graded lattices; digital image correlation; additive manufacturing
References
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How to cite this paper
@article{1722649,
author = {Bamidele Fadayomi},
title = {Failure Modes and Fracture-Path Reproducibility in 2D Honeycomb and Diamond Sandwich Architected Cores Under Quasi-Static Loading},
journal = {Iconic Research And Engineering Journals},
year = {2024},
volume = {7},
number = {10},
pages = {767-778},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1722649.pdf},
abstract = {Architected sandwich cores are widely adopted for their stiffness-to-weight efficiency, yet the literature remains weighted toward stiffness and energy-absorption metrics, with comparatively little systematic data on how such cores actually fracture. This study reports a controlled experimental investigation of failure modes, load-response classification, and fracture-path reproducibility in two-dimensional honeycomb and diamond sandwich cores under quasi-static loading. Eight core configurations were examined: honeycomb at unit-cell angles of 15°, 30° and 45°, diamond at 45°, 90° and 120°, and a functionally graded variant of each topology in which vertical cell height was graded through the core thickness. All specimens were additively manufactured from a UV-cured brittle photopolymer resin, deliberately selected so that fracture rather than plastic collapse would govern, and tested in five replicates per configuration under three-point bending and uniform quasi-static compression. Full-field deformation was recorded by two-dimensional digital image correlation. Core shear governed failure in every honeycomb configuration under both loading modes, whereas the diamond topology exhibited a mode transition with cell angle: buckling dominated at 45° and 90°, while the 120° and functionally graded configurations deformed in a bending-dominated manner with minimal fracture. Load responses conformed to Type II behaviour for the honeycomb and lower-angle diamond cores, with the 15° honeycomb exhibiting a partial Type II response, and to Type I behaviour for the 120° and functionally graded diamond cores. Fracture paths were reproducible in a well-defined subset of configurations, recurring as 180° straight and 120° oblique propagation lines, while the remaining configurations showed no repeatable path. This division is attributed to the interaction between loading-nose position and core strut placement in specimens without enforced core symmetry. The functionally graded cores concentrated deformation within targeted compliant regions while leaving stiffer regions intact, demonstrating spatially programmable failure. The resulting failure-mode map and reproducibility classification provide a quantitative reference dataset for validating numerical models of architected core fracture.},
keywords = {architected materials; sandwich structures; honeycomb; diamond lattice; failure modes; fracture reproducibility; functionally graded lattices; digital image correlation; additive manufacturing},
month = {April},
}