Letecký ústav

Browse

Recent Submissions

Now showing 1 - 5 of 28
  • Thumbnail Image
    Item
    Enhancing UAS safety through building-induced dangerous zones prediction: concept and simulations
    (Vilnius Gediminas Technical University, 2024-12-19) Balážová, Renáta; Hlinka, Jiří; Gábrlík, Petr; Santus, Alessandro; Ferrari, Simone
    This study presents a comprehensive approach to operational estimation of the zones of danger for the Unmanned Aerial Systems (UASs) generated at low altitudes in presence of buildings, aimed at ensuring their safer operation. The main tasks are three. The first one is the definition of an inboard measurement methodology appropriate and feasible for UAS that allows Eddy Dissipation Rate (EDR) estimation. An inboard setup with a lightweight and low-cost anemometer operating at a 1 Hz sampling rate, immediately usable on UAS, is proposed. The second one is the definition of empirical equations to estimate the size of dangerous areas for the UAS flights around buildings through numerical simulation. The third one is the validation of the empirical formulas in a real-world case, through the numerical simulation of a group of buildings belonging to a research centre. Results show a good resemblance in the size of the danger zones, highlighting that this multi-faceted approach contributes to enhanced safety protocols for UASs operating in urban environments.
  • Thumbnail Image
    Item
    Multidisciplinary Design Optimization Framework for Morphing Wing using Metamaterials
    (IEEE, 2025-01-28) Zikmund, Pavel; Kofler, Michael; Navrátil, Jan; Hrstka, Miroslav; Pollák, Jakub; Van Kampen, Erik-Jan
    Metamaterials offer innovative potential for morphing wing design. This study investigates two approaches: a variable-stiffness leading edge and a trailing edge with a metamaterial lattice hinge, applying Multidisciplinary Design Optimization to compare these designs against a conventional composite wing. Aerodynamic, structural, and control analyses are integrated, with initial findings bridging 2D aero-structural wing rib design and 3D aerodynamic and control evaluations.
  • Thumbnail Image
    Item
    More Haptic Aircraft
    (IOP Publishing Ltd, 2024-03-13) Zikmund, Pavel; Horpatzká, Michaela; Procházková, Hana; Macík, Miroslav
    This 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.
  • Thumbnail Image
    Item
    Research of Effects of Defects on Stability Failures of Semi-monocoque Stiffeners
    (Vilnius Gediminas Technical University (VGTU) Press, 2020-01-22) Katrňák, Tomáš; Juračka, Jaroslav; Jebáček, Ivo
    This article presents further results of the research of effects of model defects on the local buckling of compressed stiffeners in nonlinear finite element (FE) analyses. The main outcomes are confirmation of trends for 10 sets of profile dimensions, final validations of various sets of FE simulations, and designs of practical types of defects with appropriate ratio values. A single node defect and then complex types of defects with alternating distributions of node shifts along one edge, two free flange edges, one flange surface and both flange surfaces are analyzed in this research project. First parts of this paper describe designed FE models with defects, their effects on simulation results, colored graphic visualizations with stress scales and determinations of the sudden failure of stability in the local mode. Then, particular results of FE analyses are validated by a comparison with the results of analytical methods of stability failure. Final detail comparisons of analytical and FE simulation results with data of experimental tests confirm predicted critical buckling forces. The validation of results and design parameters together with the knowledge of effects of model defects on buckling behaviors allows more accurate simulations of internal stiffeners of thin-walled semi-monocoque structures.
  • Thumbnail Image
    Item
    Modifications of a simple I-beam and its effects on the stress state
    (Taylor & Francis, 2016-12-20) Cejpek, Jakub; Juračka, Jaroslav
    The motivation for this work is a desire for a deeper understanding of the structural failures in a composite glider wing, which has been tested in the laboratories of the Institute of Aerospace Engineering, Faculty of Mechanical Engineering, Brno University of Technology. To understand the causes of the encountered failures, one has to consider the effects of all the stages in the design, manufacturing and testing of the wing. This paper focuses only on the design stage. The presented facts were obtained from a finite element analysis. The geometry used for the analysis is that of the tested specimens. This allows validating the results by the comparison of the deformation and strains measured during the laboratory tests. The analysis starts with a simple I-beam loaded by three-point-bending. In the next step a cantilever is added. Several more modifications follow, changing the I-beam to the wing. The case evaluation considers the interaction between normal (material direction 1) and inter-laminar shear stresses in the upper flange. The goal of this paper is to quantify the effect of each design change in the wing structure and loading on the stress plane 1-31.