This article investigates the impact of changes in the internal structure of composite materials on their dynamic properties. The present research focuses on 3D-printed specimens with different reinforcement fiber arrangements. The specimens are printed on a Markforged Mark Two 3D printer. The base material is nylon filled with chopped carbon fibers (Onyx) and the reinforcement is in the form of long carbon, glass and Kevlar fibers. The experiment is carried out by the impact method. The principle of this method is to expose the specimen to a short impulse of force while monitoring its frequency response. The obtained results determine the natural frequencies and internal damping of the individual structures. We found that the highest damping is achieved by specimens with glass and Kevlar fibers in 45°, 90° and ±45° configurations. On the other hand, the lowest damping is achieved by specimens with carbon fibers and 0° and 0°,90° configurations. Also, the specimens with circumferential reinforcement show lower damping coefficient values. The knowledge and results of this work can be used in the development of new components; for example, in the transport industry, where the low weight and sufficient strength of components are important factors. These components have to absorb vibrations from various sources, such as motors and external influences.

This paper examines the design of a maintenance shaft hatch cover at an airport service road which will be utilized at airports in the European Union. The shaft has a particular application: it will be used for information networks and airport security. The hatch is also subject to extremely stringent safety criteria. For instance, in a catastrophic case, a wheel from an aircraft could strike the hatch cover. Based on all the input information and after a thorough analysis of the European standards concerning the safety of transport, after performing numerous FEM static evaluations, a hatch cover that can be utilized in airport infrastructure was created. As a result of the FEM analyses, the elements with the greatest impact on static safety were identified. Finally, a simulation of stress tests based on the traffic areas for which the hatch cover was designed, in terms of traffic safety, was carried out. The test led to a positive result, showing that it is possible to apply the hatch directly in practice.

The thesis focuses on the analysis and calculation of the aerodynamic lift force of the propeller that is applied to the drone. The unmanned aerial vehicle, a drone, can be remotely controlled or capable of autonomous flight using pre-programmed flight plans or more complex dynamic autonomous systems. The main input is a model of the propeller, in this particular case a model of the three-bladed propeller that is used on the drone. The thesis summarizes the theoretical knowledge of the physics of flight. Subsequent analysis and mathematical calculation establishes the dependence of the lift force on the rotation of the propeller, which is shown in the table. The result of the work is the maximum load that the propeller can sustain in the process of flight due to the aerodynamic lift force.