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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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Design of auxetic structures for the 3D print
Sobol, Vítězslav ; Škaroupka, David (referee) ; Červinek, Ondřej (advisor)
Behavior in which the material expands in one direction and in a perpendicular direction under tensile loading is called auxetic and is associated, e. g. with increased indentation resistance. Auxetic behavior is mainly due to the typical geometry of the internal structure. Therefore, it can be achieved by a unique arrangement of inner micro-lattice structure. Through additive technologies such as Selective Laser Melting (SLM), it is possible to manufacture such complex geometry. This bachelor thesis deals with the design of a spatial micro-lattice structure that will exhibit auxetic behavior and can be made by the SLM method. Based on an extensive research on the topic of 2D and 3D auxetic structures, a new type of auxetic structure was designed. The manufacturability was verified by making several samples in different dimensional configurations. Auxeticity and mechanical properties were subsequently tested using a drop test. By evaluating it, it was possible to determine the influence of dimensional parameters on the overall behavior of the structure.
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Design of auxetic structures for the 3D print
Sobol, Vítězslav ; Škaroupka, David (referee) ; Červinek, Ondřej (advisor)
Behavior in which the material expands in one direction and in a perpendicular direction under tensile loading is called auxetic and is associated, e. g. with increased indentation resistance. Auxetic behavior is mainly due to the typical geometry of the internal structure. Therefore, it can be achieved by a unique arrangement of inner micro-lattice structure. Through additive technologies such as Selective Laser Melting (SLM), it is possible to manufacture such complex geometry. This bachelor thesis deals with the design of a spatial micro-lattice structure that will exhibit auxetic behavior and can be made by the SLM method. Based on an extensive research on the topic of 2D and 3D auxetic structures, a new type of auxetic structure was designed. The manufacturability was verified by making several samples in different dimensional configurations. Auxeticity and mechanical properties were subsequently tested using a drop test. By evaluating it, it was possible to determine the influence of dimensional parameters on the overall behavior of the structure.
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