Investigation of under static and dynamic load behaviors of sandwich structures produced with 3d printer

Recently, there has been an increasing interest in the potential of lattice core structures in the design and manufacture of lightweight sandwich structures for high performance engineering applications. Sandwich structures are used extensively today in the aviation, marine, automobile, windmill and construction industry sectors due to their excellent multifunctional properties, especially high bending stiffness, thermal insulation and high energy absorption capabilities. The fact that sandwich structures are used in many areas provides an excellent opportunity for the development and application of lightweight, high energy absorption and heavy duty sandwich materials. Additive Manufacturing method has enabled the production of cores with complex geometries that are impossible to fabricate. The production of sandwich structures by the additive manufacturing method provides many important advantages over traditional sandwich structures made of hexagonal honeycomb or foam core produced with traditional methods. Within the scope of the thesis, 4 different Sandwich structure models are designed. Sandwich structures are designed in the Solidworks program as Honeycomb, Re-entrant, Star and Triangle. The designed model dimensions are 40x40x20 mm for Compression and Impact tests, 130x20x20 mm for Three-point bending test. The data of the prepared models were converted to STL format to be transferred to the three-dimensional printer. Cura software, which is an intermediate program, was used to transfer the data of the models to the 3D printer. Ultimaker 3 extended FDM type 3D printer was used to manufacture sandwich structures. Sandwich structures are made of Thermoplastic polyurethane (Ultimaker TPU 95 A) material. Tensile test samples were produced to determine the mechanical properties of the material. Tensile tests were carried out on Shimadzu AG-X plus device, which was produced in 3 pieces. Models manufactured for compression and three-point bending tests were also tested on the same device. Finite element method was used for impact tests. In the finite element analysis, HyperMesh, HyperCrash, HyperView, HyperGraph, and RADIOSS software that are included in the HyperWorks package program were used. İmpact energies and energy absorption amounts of the models were obtained. The results obtained as a result of the tests were examined comparatively. According to compression, three-point bending and impact test results, the model that exhibits the best static and dynamic properties has been identified. As a result of the obtained results, it has been revealed that the Re-entrant sandwich structure model is the model with the best mechanical properties.