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- ItemMore Haptic Aircraft(IOP Publishing Ltd, 2024-03-13) Zikmund, Pavel; Horpatzká, Michaela; Procházková, Hana; Macík, MiroslavThis paper presents a comprehensive review of haptic feedback in light aircraft control. It provides an overview of the results and experiences gained from a previous research project focused on the design and testing of pilot haptic feedback hardware. The objective of this paper is to outline a roadmap for the future development of “More Haptic Aircraft,” incorporating principles of human-centred design into light aircraft cockpits equipped with the presented haptic feedback device.
- ItemAdditive manufacturing capabilities for heat switch technology: Key challenges & knowledge gaps(EUCASS association, 2022-09-28) Mašek, Jakub; Löffelmann, František; Popela, Robert; Kubík, Petr; Šebek, František; Koutný, Daniel; Malý, Martin; Pantělejev, Libor; Pambaguian, LaurentThe paper is to provide an overview of the key challenges and knowledge gaps in additive manufacturing of metals applied to two parts of a novel heat switch technology – a Baseplate and a Flexible thermal structure. Additive design, optimization and manufacturing capabilities as well as quality of produced parts were investigated. The key challenge was to manufacture bio-inspired structure without internal supports and assure 190 surfaces to be in a contact at the same time for efficient heat transfer. Finally, modern trends in additive as multi-material design and manufacturing or effect of defects are discussed for further evolution of parts.
- ItemDetermination of the Parachute Harness Critical Load Based on Load Distribution into Individual Straps with Respect of the Skydiver’s Body Position(MDPI, 2023-01-14) Grim, Robert; Popela, Robert; Jebáček, Ivo; Horák, Marek; Šplíchal, JanThis article evaluates the redistribution of forces to the parachute harness during an opening shock load and also defines the ultimate limit load of the personal parachute harness by specifying the weakest construction element and its load capacity. The primary goal of this research was not only to detect the critical elements but also to gain an understanding of the force redistribution at various load levels, which could represent changes in body mass or aerodynamic properties of the parachute during the opening phase. To capture all the phenomena of the parachutist’s body deceleration, this study also includes loading the body out of the steady descending position and asymmetrical cases. Thus, the result represents not only idealized loading but also realistic limit cases, such as asymmetric canopy inflation or system activation when the skydiver is in a non-standard position. The results revealed a significant difference in the strength utilization of the individual components. Specifically, the back webbing was found to carry a fractional load compared to the other webbing used in the design in most of the scenarios tested. Reaching the maximum allowable strength was first achieved in the asymmetric load test case, where the total force would be equal to the value of 7.963 kN, which corresponds to the maximum permissible strength of the carabiner on the measuring element three. In the same test case, the second weakest point would reach the limiting load force when the entire harness is loaded with 67.89 kN. This information and the subsequent analysis of the individual nodes provide a great opportunity for further strength and weight optimization of the design, without reducing the load capacity of the harness as a system. The findings of this study will be used for further testing and possible harness robustness optimization for both military and sport parachuting.
- ItemIMPLEMENTATION STUDY OF A PASSIVE SAFETY FEATURE IN THE RESCUE SYSTEMS OF SMALL AIRCRAFTS(VILNIUS GEDIMINAS TECH UNIV, 2023-10-13) Hájek, Tomáš; Grim, Robert; Popela, RobertArticle History: Abstract. The aim of this paper is to evaluate the feasibility of implementation of a passive safety feature in the form of an under-fuselage airbag in the rescue systems of small aircraft. The paper presents a multidisciplinary approach for the viability of the implementation. It presents the development of mathematical model for airbag performance analysis. The model is validated against the experimental data to account for various simplifications. Validated mathematical model is used to design a full-scale airbag for the chosen airplane to perform in the designed range. Weight penalty for increased safety is determined.
- ItemAn Initial Case Study of the Computational Modeling of Cord-Rubber Segments(MDPI, 2024-01-29) Láštic, Daniel; Řehák, Kamil; Prokop, Aleš; Krpalek, David; Šplíchal, Jan; Žlábek, PavelThis paper presents an initial study of the computational modeling for determining the stress-strain behavior of the cord-rubber segment, tailored to be used as a flexible member in the construction of torque transfer coupling in railway vehicles. The presented computational models use the multibody simulation approach for the assessment of segment deformation under diverse loading characteristics. The results are then used in the finite element computational models of the cord-rubber segment. The computational model is validated through tension tests of cord-rubber segments. The homogenized and microstructural models show their ability to simulate the overall stiffness of the segment relatively accurately in tension, but they are limited in not being able to include the influence of the segment's manufacturing technology. The micro-scale computational model then incorporates realistic representations of cord bundles, considering various cross-sectional shapes, whereas a very important factor significantly influencing the correlation of the results of the technical experiment and simulation is the consideration of the manufacturing technology in the process of building the computational model. The results show that the computational modeling approach in this work can be used for the determination of the optimal manufacturing technology conditions with regard to the stress-strain behavior of the given segment.