COMPUTATIONAL PARAMETRIC ANALYSES OF ENERGY ABSORPTION CAPACITIES OF DIFFERENT LATTICE STRUCTURES

Date

2024-12

Author

Karaca, İsmail Safa

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In this thesis study, the energy absorption capacities of three different lattice structures were calculated depending on variable parameters. The three lattice structures were created using hexagonal, re-entrant, and chiral unit cells. Five different parametric studies were conducted for each model by making thickness changes, angle changes of unit cells, and adding elements to unit cells. The first study engendered changes in the thickness of the horizontal and vertical edges relative to each other while keeping the weight in each model constant. The second and third studies were created by adding horizontal and vertical elements to the unit cells and changing their thickness, keeping the weight constant. In the fourth study, the angles of the unit cells were altered, and their thickness was kept constant. The weight remained steady in this case, but the relative density changed. In the fifth study, while the angles of the unit cells were changed, their thickness was also changed. In this case, while the weight varied from model to model, the relative density was kept constant. Compression analyses of all created models were conducted in mode with ABAQUS/Explicit. Then, force-displacement and stress-strain curves of the structures are generated. The locking strains, critical stresses, and plateau stresses were calculated from these curves. These values were then used to compare the energy absorption capacities for each structure, depending on the parameters. The Poisson’s ratios at different strain values were computed, the effects of parameter changes on Poisson’s ratios were examined, and the relationship between Poisson's ratios and energy absorption capacities was investigated. The structures with the highest energy absorption capacities were identified for each model. Interestingly, in most cases, the structures with Poisson's ratio close to zero also have the highest energy absorption capacity. This finding has significant implications for designing and optimizing lattice structures for energy absorption.

Subject Keywords

Auxetic Lattice Structure, Specific Energy Absorption, Plateau Stress, Locking Strain

URI

https://hdl.handle.net/11511/113001

Collections

Graduate School of Natural and Applied Sciences, Thesis