Christos-Gerasimos Koustoumpardis, "Study of the mechanical properties of cookie-shaped auxetic structure by finite element analysis", Diploma Work, School of Production Engineering and Management, Technical University of Crete, Chania, Greece, 2023
https://doi.org/10.26233/heallink.tuc.94891
Metamaterials are a category of artificially manufactured materials that exhibitextraordinary properties not available or not easily obtainable in natural materials.Because of these properties, they are ideal choices for a plethora of applications.Therefore, the thorough study of the properties of metamaterials as well as theirdependence on their various parameters becomes particularly important.A subcategory of these materials is auxetic materials, which present a negative Poissonratio and, by extension, an inverse deformation mechanism. That is, when compressivestress is applied to the longitudinal axis, auxetics contract transversely, contrary tomaterials with a positive Poisson's ratio, which expand under corresponding stress.In this thesis, the auxetic 4-petal cookie-shaped structure is generated through a set ofequations. The design of the structure is created in Autodesk's Inventor program. Thenthe effect of each parameter on Poisson’s ratio as well as the stiffness is studied. Thesevalues are calculated by finite element analysis in Autodesk's Inventor Nastranprogram. Finally, as a case study, a grid of the above auxetic structure is placed as aninfill of a robotic gripper. This application investigates the ability to hold objects by themechanism, as well as the stresses created within the mesh during the holding process.