Silvia Maláková

Hydraulic lifting platforms enable firefighters and rescue workers to respond effectively and safely in difficult conditions. Machinery must comply with safety requirements, and protective measures must be designed in accordance with the principles of EN ISO 12100 for hazards and risks. Operators of this equipment must undergo training to be able to use this type of firefighting equipment correctly and effectively, with regard to their own safety and the safety of the people being rescued.

This paper presents a numerical case study on the application of generative design to the shape optimisation of a spur gear body with consideration of manufacturing constraints and material properties. The presented results are obtained using numerical simulation and finite element analysis. A finite element-based generative design workflow was employed to evaluate weight reduction and stiffness performance under different manufacturing routes, including additive manufacturing, machining, and casting. The results show that the application of generative design enabled a gear-body mass reduction of up to 37.46–45.68% compared to the reference geometry while maintaining acceptable deformation levels. Designs constrained for additive manufacturing achieved the highest weight savings, whereas machining-constrained variants exhibited lower deformation values, indicating higher structural stiffness. Casting-oriented constraints resulted in more conservative geometries with locally reinforced regions. The study confirms that manufacturing constraints significantly influence the generated geometry and mechanical response, demonstrating that the manufacturing route acts as an independent design variable within the generative design process. The presented methodology provides practical guidance for the early-stage numerical optimisation of gear bodies and supports informed decision-making with respect to manufacturing technology selection.

This work investigates the application of generative design in the development of gear wheels, with emphasis on the relationship between geometry, manufacturing technology, and material selection. Material properties such as strength, stiffness, fatigue resistance, and manufacturability significantly influence both the achievable level of shape optimization and the resulting weight reduction. Generative design enables the adaptation of gear-body geometry to the mechanical characteristics of individual material classes, supporting efficient material utilization while ensuring the required stiffness. The study evaluates the effects of various manufacturing technologies—additive manufacturing, subtractive machining, and casting—by considering material processability and structural constraints. The results demonstrate that the combination of material and manufacturing method substantially shapes the design space: additive manufacturing allows lightweight and organic structures with high geometric freedom; milling requires tool-accessible geometries; and casting benefits from local reinforcement in the area around lightening holes, improving stiffness and stability. The analyses confirm that material selection is a decisive factor in the effectiveness of generative gear design, as an appropriate choice contributes to an improved balance between weight, stiffness, and production cost. The presented framework integrates shape optimization, load evaluation, and material constraints to support the development of innovative, efficient, and manufacturable gear geometries for modern engineering applications.

Topological optimization uses two main optimization conditions aimed at achieving the maximum stiffness at minimum weight of the loaded object, while not exceeding the allowable stress. This process naturally creates complex structures with varying degrees of density. There is a certain regularity between the density of the structure and stiffness, with the optimal density being related to the golden ratio. This study contributes to materials modeling and their characterization by introducing a mathematical theory related to the virial theorem as a predictive framework for understanding stiffness–density relationships in additively manufactured structures. The definition of virial stability and the methodology for deriving this stability from the kinetic and potential components of a random signal are introduced. The proposed virial-based model offers a generalizable tool for materials characterization, applicable not only to topological optimization but also to broader areas of materials science and advanced manufacturing.

The paper focuses on the experimental investigation of the impact of filtration and tribological parameters on the reliability, service life, and functional characteristics of gear mechanisms used in robotics. The primary objective was to analyze the importance of lubricant cleanliness in robotic transmission modules and to assess the effectiveness of filtration as a preventive and protective measure. As part of the research, a dedicated test rig was designed and developed. Based on the measurements and analyses performed, a significant correlation was confirmed between lubricant contamination levels and degradation phenomena in transmission modules. The study also highlights a sharp increase in contamination during the initial hours of operation, emphasizing the need for early intervention and continuous monitoring. The findings have strong practical potential and are highly relevant for manufacturers of robotic systems, maintenance service providers, and operators of automated production lines. The results contribute to increased system reliability and extended service life, reduced maintenance and repair costs, and improved environmental aspects of robotic system maintenance.

The paper focuses on the experimental investigation of the impact of filtration and tribological parameters on the reliability, service life, and functional characteristics of gear mechanisms used in robotics. The primary objective was to analyze the importance of lubricant cleanliness in robotic transmission modules and to assess the effectiveness of filtration as a preventive and protective measure. As part of the research, a dedicated test rig was designed and developed. Based on the measurements and analyses performed, a significant correlation was confirmed between lubricant contamination levels and degradation phenomena in transmission modules. The study also highlights a sharp increase in contamination during the initial hours of operation, emphasizing the need for early intervention and continuous monitoring. The findings have strong practical potential and are highly relevant for manufacturers of robotic systems, maintenance service providers, and operators of automated production lines. The results contribute to increased system reliability and extended service life, reduced maintenance and repair costs, and improved environmental aspects of robotic system maintenance.

Gears are very common machine components that enable precise transmission of rotational motion and power transmission from shaft to shaft. High demands are placed on the function of gears in operation. They must enable precise, uniform transmission, must not cause noise, often have to transmit large forces, etc. Gears are manufactured from a variety of materials and with different performance specifications depending on the industrial application. Gear materials are required to have high strength, toughness and wear resistance because gears rely on their own design size and material strength to withstand external loads. Material manufacturability is also necessary due to the complex shape of the gear and the high precision requirements of the gear. This study highlights trends in gear materials that are moving towards ultra-high strength, high wear resistance, high temperature resistance, corrosion resistance, and low weight.

This paper investigates the complex interaction between material selection, heat treatment processes, and strength calculation methodologies in the design of gear transmissions. The mechanical performance and durability of gears are highly dependent on the choice of base material and the subsequent thermal treatments applied to optimize their microstructure and mechanical properties. We analysed how different heat treatment techniques, such as carburizing, quenching, and tempering, influence the microstructural characteristics and fatigue strength of common gear materials. Furthermore, the study evaluates how these material and heat treatment factors are integrated into strength calculation models used in gear design to predict operational lifespan and reliability. Experimental data and numerical simulations are employed to validate the correlation between processing parameters and gear performance. The findings highlight the critical role of a holistic design approach that considers material properties, heat treatment parameters, and accurate strength calculations to enhance gear transmission efficiency and longevity.

Non-standard gear transmissions are increasingly finding their applications in practice, primarily being designed for various applications. While standard circular gears are designed for a constant gear ratio, non-standard gears have a variable gear ratio that changes. This paper addresses the issue of designing non-circular gears for a specific range of gear ratios. An elliptical shape for the gears was chosen. The uniqueness of the proposed solution lies in selecting an ellipse as the evolute for creating the involute curve of the gear tooth.

The subject of the research presented in this article is the dimensional optimisation of the box structure of the main girder for overhead cranes, with the aim to reduce the main girder’s own weight. Described are the applied optimisation methods and also the problems arising during the optimisation process. Loss of shape stability is analysed in more detail, as well as the methods determined for a constructional proposal of the girder cross-section. The developed optimisation procedure is a combination of the calculations, performed in the MS Excel environment, with the simulation of a parametrically modelled girder realised using Dassault Systèmes SolidWorks software v. 2023. Using the example of optimisation of an overhead crane girder with a lifting capacity of 50 tons, the effectiveness of the proposed optimisation procedure is declared, where the existing overhead crane box girder is compared with the optimised cross-section of the box girder.