Steel of the mild-strength S355J2+N steel grade is the most often used steel for manufacturing carrying sections of constructions exposed to fatigue loads. The use of high-strength steels, such as S690QL, allows for the creation of structures that are light and simple to construct. However, increasing the yield strength of high-strength steels does not result in a corresponding increase in fatigue resistance. As a result, using high-strength steels for constructions subjected to fatigue loading can be a major design concern, raising the question of whether high-strength steels should be used at all. Most of the experimental investigations regarding the hot work tool steel X37CrMoV5-1 found in the literature are focused on its machining and wear resistance, with insufficient attention paid to the cyclic loads. This article evaluates the fatigue properties of mild-strength S355J2+N, high-strength S690QL, and X37CrMoV5-1 steel grades. A SHIMADZU servo-hydraulic testing machine is used to perform uniaxial tensile tests under uniaxial fatigue stress-controlled, fully reversed conditions (tensile–compression testing with R = −1 stress ratio) in accordance with EN ISO and ASTM standards. The aim of this paper is to highlight the fatigue characteristics of these three steels that are among the most used in their respective groups. Steel S355J2+N belongs to the group of hot-rolled normalized steels, S690QL belongs to the group of improved (quenched + tempered) steels with increased strength, and X37CrMoV5-1 belongs to the group of high-alloyed tool steels for hot work. This choice was made as the tested steels can be considered typical representatives of their groups. Based on the test results of these three steels, which are organized in S–N curves, the fatigue behavior of the entire mentioned groups of steels can be foreseen.

The reliability study is the most important part of the engineering design process, as it is the basis of analysis and assessment of future product performance in exploitation. Since performance cannot be predicted with absolute certainty, the application of reliability theory includes probability theory and unreliability modeling. The proposed approach has been applied to assess the reliability of gear planetary power transmissions. The assessment of system reliability was determined on the basis of the block diagram method, as a function of the reliability of individual components, calculated by statistical analysis. Using the Weibull model, the reliability of the planetary gear was defined on the basis of the probability of failure of the gear teeth and the results were interpreted to assess the reliability of the component and the entire planetary train. For a more precise assessment of reliability and to avoid modeling every failure and mode of occurrence, a competitive risk model was developed. The reliability assessment study was conducted with a “bottom-up” approach. Reliability has been assessed, for instantaneous, estimated and assigned failures rate of planetary train and component.

Use of composite materials has seen significant growth, especially in the manufacture of lightweight structures and biomedical applications. One type of composite material is made up of polymer materials reinforced with glass fibres. PA6-GF reinforced with 25 % chopped glass fibres is a representative of this composite material group. The manufacturer recommends annealing as a heat treatment process after production. However, annealing requires additional equipment and time. This paper seeks to investigate the effect of non-annealed PA6 GF on the Charpy impact properties. Samples for Charpy impact property tests are defined according to BAS EN ISO 179-2:2021. The test specimens were printed on the FlashForge Creator 3 PRO printer, and the testing was performed on the AMSLER RPK300 device.

The aim of this paper is to present a theoretical model for efficiency evaluation of a simple cycloid drive train with one degree of freedom (DOF) or constrained cycloid drive. In order to evaluate the efficiency, it is necessary to find the losses g...

Determining the load capacity of machine parts used in the transport of heavy profiles is a challenging, but also very responsible task for any engineer. This process requires a detailed analysis of loads, deformations and critical points where local damage or system failure can occur. In modern mechanical practice, the application of the finite element method (FEM) is becoming an indispensable tool due to its precision in predicting the behavior of materials, as well as the ability to quickly and efficiently vary geometry and boundary conditions. FEM enables the simulation of real working conditions of the structure with minimal costs of experimental testing, which gives engineers wider possibilities in optimizing structural solutions. The load-bearing capacity of steel profiles is influenced by a number of parameters, among which the choice of material the method of support and stiffening of elements, geometric shape, as well as the appearance of sources of stress concentration that can lead to the initiation of cracks and reduced reliability. Each of these factors must be carefully considered in the design process to ensure the safety and longevity of the structure. Through this study, the process of variation of the geometry of the developed assembly for the transmission of massive profiles in the production hall is shown. The analysis was carried out taking into account key criteria such as the safety of the structure in operation and the overall reliability of the system. The results obtained indicate the importance of an integrated approach, where theoretical models and numerical simulations are combined with engineering experience in order to optimize the load-bearing capacity and long-term usability of the structure.

This work presents the application of CAD tools on the example of a hydraulic lifting table. The mechanism was modeled in Autodesk Inventor and analyzed through motion simulation and static calculation using the finite element method. The results indicate that CAD software accelerates development, reduces costs, and enables timely corrections within the virtual model.