High fracture toughness micro-architectured materials

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2020-10
Major/Subject
Mcode
Degree programme
Language
en
Pages
18
Series
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, Volume 143
Abstract
We investigate the possibility of achieving high fracture toughness and high strength by the design of lightweight (density below water) metallic micro-architectured materials. The micro-architectured materials were manufactured by drilling a hexagonal array of holes in plates of an aluminum alloy, and the fracture toughness was evaluated via three-point bend tests of single-edge notch specimens. The results show that the fracture toughness of micro-architectured materials increases with increasing relative density and remarkably, a micro-architectured material can be 50% lighter than the parent material but maintain the same fracture toughness. Additional tests on geometrically similar specimens revealed that the fracture toughness increases linearly with the square-root of the cell size. The experiments are complemented by finite element calculations of ductile fracture. In the calculations, the fracture toughness of single-edge notch specimens subjected to three-point bending are evaluated using both, a procedure similar to the experiments and direct computation of the J-contour integral. The fracture toughness as calculated by both methods are consistent with the experimental results. In addition, the calculations are also carried out for single-edge notch specimens subjected to tensile loading, confirming the validity of the measured fracture toughness as a useful material property independent of specimen geometry.
Description
Keywords
Crack propagation and arrest, Finite elements, Fracture toughness, Mechanical testing, Micro-architectured materials
Other note
Citation
Liu , Y , St-Pierre , L , Fleck , N A , Deshpande , V S & Srivastava , A 2020 , ' High fracture toughness micro-architectured materials ' , JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS , vol. 143 , 104060 . https://doi.org/10.1016/j.jmps.2020.104060