Experimental and numerical investigation of mechanical properties of additively manufactured auxetic structures

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2022-8

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Taşdemir, Mehmet

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In this thesis, two novel unit cell designs were constituted by combining different auxetic structures in literature, and they were produced via the 3D printers, which is one of the most popular additive manufacturing methods nowadays. Based on the unit cells produced with various parameters, tensile and compression samples were manufactured and the mechanical properties of auxetic structures and their feasibility in the field of additive manufacturing were investigated. Although polymer-based materials are accepted as the base material of 3D printing technology, titanium and its alloys can also be used in various engineering applications such as additive manufacturing. In this context, the production of the samples was carried out using PLA and Ti6Al4V alloy, the specimens were subjected to tensile and compression tests, and their mechanical properties were investigated. Afterward, the microstructures of the samples were investigated by means of microhardness, SEM, FTIR, XRD, TGA, and DSC analyses. Furthermore, with Finite Element Analysis, the tensile and compression tests of the samples were simulated in the computer environment and their comparisons with the experimental results were also carried out. In this thesis study, it was observed that the tensile and compressive strength of the unit cell increased as the angle between the branches forming the unit cell decreased. Furthermore, it was also achieved that the increase in the thickness values of the branches constituting the unit cell also leads to an increase in the tensile and compressive strength values of the unit cell.

Subject Keywords

Auxetic materials, Negative Poisson's ratio, Lattice geometries, Additive manufacturing

URI

https://hdl.handle.net/11511/98777

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

M. Taşdemir, “Experimental and numerical investigation of mechanical properties of additively manufactured auxetic structures,” M.S. - Master of Science, Middle East Technical University, 2022.