| Abstract [eng] |
The project encompassed an investigation upon auxetic and hexagonal structures, which are two types of lattice structures that have attracted significant attention in recent years. Both structures have unique mechanical properties that make them ideal for various applications, including aerospace, medical devices, and sports equipment. The auxetic structure is characterized by a negative Poisson's ratio, making it expand in the transverse direction when stretched in the axial direction. In contrast, the hexagonal structure has a positive Poisson's ratio, which means that it contracts in the transverse direction when stretched in the axial direction. The auxetic structure is known for its exceptional energy absorption ability, while the hexagonal structure is known for its high stiffness and strength. To further investigate the mechanical properties of the structures, SolidWorks software was used to simulate their behaviour under compression. The simulations indicated that the auxetic structure had a more uniform stress distribution compared to the hexagonal structure. To compare the mechanical properties of these structures, compression tests were performed using a universal testing machine, after 3D printing them using an FDM printer. The results showed that the auxetic structure had a higher compressive strain compared to the hexagonal structure. This can be attributed to the unique deformation mechanism of the auxetic structure, which involves the rotation of the unit cells. The hexagonal structure, on the other hand, deformed through bending and stretching of the unit cells. Based on the performed cost analysis, it was concluded that the choice between the auxetic and hexagonal structures depends on the specific application requirements. If high energy absorption capacity and resistance to localized failure are critical, then the auxetic structure would be a better option. However, for high stiffness and strength the hexagonal structure would be a better option. By comparing their mechanical properties and printing characteristics, the advantages and disadvantages of each structure were highlighted, and insight were provided into their cost-effectiveness. |
