This paper presents a newly developed system for mechanical testing at static loading. The separate modules of the system are described - tensile testing machine, grips, extensometers for axial end transverse deformations, electronic control system. The results obtained during tensile testing with the new system are given. The yield strength, the tensile strength, the elasticity modules and the Poisson’s ratio of general purpose steal S235JRC are determined.

Studies show that although commonly used steels are standardized, some of their mechanical properties (such as tensile strength) vary widely and knowledge of their corrosion behavior is insufficient. Additional treatments, such as plastic deformation, alter the structure of carbon steels and affect their properties. This article explores one of the most widely used materials in mechanical and civil engineering - steel S235. Two types of rods, 6 mm in diameter, from hot-rolled non-alloy structural steel (S235JR, BDS EN 10025-2: 2005) and bright cold drawn steel (S235JRC, BDS EN 10277-2: 2008) have been tested. Tensile tests have been carried out, stress-strain curves are constructed and compared, the main mechanical properties such as yield strength, tensile strength and modulus of elasticity are determined. The typical consequences of plastic deformation such as increased yield strength have been identified. The assessment of corrosion behavior was done by means of the weight loss method in a 3,5% NaCl water solution for 5 weeks. It was found out that in the studied period the two types of rod exhibit close corrosion resistance, with the tendency for the cold drawn steel to have a higher uniform corrosion rate over a longer period.

In this work, a comparative analysis of polymer test specimens from different types of filaments, manufactured using FDM technology, was performed. A tensile strength test was executed on test specimens after 3D additive printing, made from different groups of materials—PLA, PLA Wood, PETG, PC, PA6, ASA, CPE HG100 and FilaFlex SEBS. Test specimens from the same materials were subjected to accelerated aging, after which they were tested again for tensile strength. The results of all tests were analyzed and compared.

The paper investigates experimentally the influence of infill density, infill pattern, layer height, wall number, printing orientation, and material color on the impact strength of 3D-printed PLA (polylactic acid) samples by using the Charpy test method. The used printing method is FDM (Fused Deposition Modeling) performed on a desktop printer. For each parameter changed in the study, five separate unnotched specimens were produced and tested, and the average impact strength value was taken into account. The filament rolls went through a drying process before printing and were then stored in a low-humidity environment filled with desiccant in order to minimize the effect of absorbed humidity in the filament during the experiments. The conditioning and testing of samples were performed according to the EN ISO 179-1 standard. Dimensional accuracy, print times, and filament consumption were also estimated in the study. The results revealed that the infill density, infill pattern, and wall number have a larger influence on the impact energy absorbed by the samples in comparison to the layer height, printing orientation, and the PLA filament color. The best optimization of the studied mechanical property was obtained by increasing the infill percentage and the number of walls. Applying different PLA colors has a slight effect on the impact strength, yet it should be taken into consideration when designing 3D-printed products that are intended to withstand impact. Moreover, it was found out that the studied parameters have an insignificant effect on the dimensional accuracy of the produced samples.

Very few experimental studies of full pinion engagement planetary gear trains have been published; therefore, their behavior under load is little known. In this paper, the results from the experimental studies of the above-mentioned gear trains are presented, whereby the bending stresses in the planet pins are displayed both in time and frequency domains by means of fast Fourier transform (FFT). The experiments are conducted on a mechanical closed-loop test rig, which was designed especially for the experiments. The bending stresses in the pins are measured by strain gauges, which are mounted in a double half-bridge configuration, thus showing the stresses in two perpendicular planes. The torque applied is 200 Nm. The radial run-out errors of the planets are measured and their relation to the pin loads are analyzed.

Shape-memory alloys have various applications in different fields including medicine, robotics, aeronautics, and micro-electromechanical systems. This paper discusses shrink-fit joints formed by shape-memory alloy elements and their application for the axial fixation of mechanical components. The use of shape-memory alloys gives the shrink-fits some specific features: ease of assembly, insensitivity to tooling and human error, chemical resistance, low cost, etc. The friction force created between the components is experimentally investigated as a function of two parameters—the substrate diameter and the surface roughness (Ra) of one of the joined elements. The results of the experiments are presented analytically and graphically. Conclusions are drawn regarding the behavior of the studied shrink-fits. They can be beneficial to any engineering project making it less sensitive to manufacturing variations.