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Honeycomb sandwich composites are widely used in many industries. It is important to determine the impact strengths resulting from low-velocity impacts that sandwich composites may encounter in accordance with their intended use. In this study, the low-velocity impact performance of sandwich composites, which are combined with carbon fiber reinforced composite plates (CFRP) on the top and bottom surfaces of the cores produced from polylactic acid (PLA) filament in 3D printer, using honeycomb geometries with three different cell widths and cell wall thicknesses were investigated. Honeycomb geometries with three different cell widths and cell wall thicknesses of 6_0.8mm, 9_1.2mm and 12_1.6mm, respectively, were used in the study. In order to obtain equal surface area in samples exposed to low-velocity impact, these measurements were preferred by increasing both cell width and cell wall thickness. Low-velocity impact tests at five different energy levels (30J, 40J, 60J, 80J and 100J) were applied to honeycomb sandwich composite samples produced in dimensions in each geometry, and the sandwich composites were full perforated at 100J impact energy. Sandwich structures with the smallest cell width and the highest number of cells with 6mm cell width showed better performance against impact at 30J, 40J and 60J impact energy levels. With increasing impact energy, sandwich structures with three different cell widths at 80J and 100J energy levels were found to have similar performance against impact. [ABSTRACT FROM AUTHOR]

Today, 3-dimensional (3D) printers are developing increasingly, and rapid progress is being made to become an alternative to traditional production methods. 3D printers, which produce with the Fused Deposition Modeling (FDM) method, commonly produce by using polymer materials in the form of filament with a diameter of 1.75 mm or 2.85 mm. This study, tensile test specimens were produced using PLA filaments of different diameters (1.75 mm and 2.85 mm) with two different 3D printers. The electricity consumption of 3D printers during the production of tensile test samples was measured. The energy consumed by both 3D printers in producing tensile test specimens was compared. Instead of simultaneously producing a single test sample, it has been determined that the power consumption per test sample will be reduced by producing many test samples together. [ABSTRACT FROM AUTHOR]

In this study, tensile test specimens have been produced using ABS (acrylonitrile butadiene styrene) and PLA (poly-lactic acid) material at different printing speeds (20-40-60-80-100-120-140mm/s) with Ultimaker 2 Extended 3D printer. The effect of printing speed on mechanical properties has been investigated. Masses, hardness and surface roughness of the produced samples have been measured, porosity values have been calculated and tensile test has been performed on the produced samples. After the tensile test, images have been taken by scanning electron microscopy (SEM) from the breaking regions of the broken samples. The mechanical properties of the samples produced with the same parameters with both materials have been compared. As a result; it has been determined that the tensile strength of the samples produced with PLA material are higher than the samples produced with ABS material, and the elongation at break values of the samples produced with ABS material are higher than the samples produced with PLA material. [ABSTRACT FROM AUTHOR]