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Design of high-performance auxetic structure for energy absorption
Sobol, Vítězslav ; Hutař, Pavel (referee) ; Červinek, Ondřej (advisor)
Additive technologies enable the production of complex structures with high control over their geometric parameters. In the field of energy absorption, it is advantageous to use a structured material because they can safely absorb large amount of energy. For high-performance absorbers, it can be advantageous to use auxetic structures which, due to their unique internal geometry, provide, e.g. better energy redistribution. Compared to conventional structures, however, they do not achieve such high values of absorbed energy. Also, literature does not offer a detailed description of the mechanisms of absorbed energy increase, based on which the geometry of the auxetic structure could be effectively modified. This thesis dealt with the systematic design of the internal geometry of a 2D auxetic structure to increase the absorption performance. Five different arm geometries were tested as well as cells with reinforcements with stepped distance from the centre of the cell. Compression testing showed a low dependence of the arm geometry used and a significant benefit of the reinforcements on the energy absorbed. The DIC technology provided deformation maps of structures, which led to the clarification of the energy increase mechanism by the reinforcement implementation. The results obtained led to an auxetic structure that was able to absorb 70 % more energy per unit mass compared to the reference geometry.
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