ABSTRACT
Gyroid structures are among the most widely used three-dimensional elements produced by various additive manufacturing technologies. This paper focuses on a metrological analysis of Flexfill 92A material specimens with a relative density (25 to 85%) using industrial computer tomography. The results show that for a given structure, the best method is to use surface determination with the closure of internal defects in the material. The analysis implies that the smallest deviations of the specimens' external dimensions were achieved with respect to the CAD model at the highest relative densities. The wall thickness shows the smallest percentage change of 0.5685 at 45% relative density and the largest at 25% and 85% relative density. The nominal-actual comparison of manufactured specimens to the CAD model shows the smallest cumulative deviation of 0.209 mm at 90% and 25% relative density, while it slightly increases with increasing relative density. All produced specimens have a smaller material volume than their theoretical volume value, while the percentage change in volume is up to 8.6%. The surface of specimens is larger compared with the theoretical values and the percentage change reaches up to 25.3%. The percentage of pores in the specimens increases with increasing relative density and reaches 6%. The acquired knowledge will be applied in the framework of research focused on the possibilities of using additive manufacturing to produce a skeleton of rubber-textile conveyor belts. This paper presents initial research on the possibility of replacing the carcass of rubber-textile belts with an additive technology use.
ABSTRACT
The development of additive technology has made it possible to produce metamaterials with a regularly recurring structure, the properties of which can be controlled, predicted, and purposefully implemented into the core of components used in various industries. Therefore, knowing the properties and behavior of these structures is a very important aspect in their application in real practice from the aspects of safety and operational reliability. This article deals with the effect of cell size and volume ratio of a body-centered cubic (BCC) lattice structure made from Acrylonitrile Butadiene Styrene (ABS) plastic on mechanical vibration damping and compression properties. The samples were produced in three sizes of a basic cell and three volume ratios by the fused deposition modeling (FDM) technique. Vibration damping properties of the tested 3D-printed ABS samples were investigated under harmonic excitation at three employed inertial masses. The metamaterial behavior and response under compressive loading were studied under a uniaxial full range (up to failure) quasi-static compression test. Based on the experimental data, a correlation between the investigated ABS samples' stiffness evaluated through both compressive stress and mechanical vibration damping can be found.
ABSTRACT
Noise pollution is a negative factor that affects our environment. It is, therefore, necessary to take appropriate measures to minimize it. This article deals with the sound absorption properties of open-porous Acrylonitrile Butadiene Styrene (ABS) material structures that were produced using 3D printing technology. The material's ability to damp sound was evaluated based on the normal incidence sound absorption coefficient and the noise reduction coefficient, which were experimentally measured by the transfer function method using an acoustic impedance tube. The different factors that affect the sound absorption behavior of the studied ABS specimens are presented in this work. In this study, it was discovered that the sound absorption properties of the tested ABS samples are significantly influenced by many factors, namely by the type of 3D-printed, open-porous material structure, the excitation frequency, the sample thickness, and the air gap size behind the sound-absorbing materials inside the acoustic impedance tube.
ABSTRACT
This article explores the effect of carbon fiber content on the flexural strength of polymer concrete testing samples and compares the damping of polymer concrete and U-shaped steel profiles. The experiments involved and described herein consisted of flexural strength testing according to STN EN 12 390-5 Testing of Hardened Concrete, Part 5: Flexural Strength of Test Samples. The test results were evaluated graphically and by calculations and were further processed in various programs. The experimental results indicated that the highest flexural strength value was obtained by the test samples containing 12% of carbon fibers while culminating at 17.9 MPa. The results showed that the highest increase of flexural strength was caused by the addition of 3% of carbon fibers to the mixture, which increased the flexural strength by 4.2 MPa, or 26.75%. The results indicated that, based on the shape of the regression curve, flexural strength culminated at 13% carbon fiber content. The experimental results demonstrated that the tested polymer concrete test sample had a 6.87 times higher attenuation coefficient than the U-shaped steel profile. The results showed that the polymer concrete test sample No. 4 reduced vibration acceleration deviation by 93.5% in 0.005 sec and the U-shaped steel profile by 32.9%.
