The work concerns the experimental analysis of the process of destruction of sandwich structures as a result of circumferential shearing. The aim of the research was to determine the differences that occur in the destruction mechanism of such structures depending on the thickness and material of the core used. Specimens with a Rohacell foam core and a honeycomb core were made for the purposes of the research. The specimen destruction process was carried out in a static loading test with the use of a system introducing circumferential shear stress. The analysis of the tests results was made based on the load-displacement curves, the maximum load, and the energy absorbed by individual specimens. The tests indicated significant differences in the destruction mechanism of specimens with varied core material. The specimen with the honeycomb core was characterized by greater stiffness, which caused the damage to occur locally in the area subjected to the pressure of the punch. In specimens with the foam core, due to the lower stiffness of that core, the skins of the structure were bent, which additionally transfers compressive and tensile loads. This led to a higher maximum force that the specimens obtained at the time of destruction and greater energy absorption.
The presented work considers the issue of the usefulness of alternative methods aimed at quickly and effectively identifying the local damage to the thin-walled composite load-bearing structures. Two ways of identifying destruction were considered, based on the assumption that the damage that occurs during operation causes local changes in the system rigidity. The first method is based on strain gauges. It consists of embedding strain gauges in the structure at the stage of composite production and monitoring of deformation during its life cycle. The second of the concepts under consideration is based on modal analysis, carried out using a modal hammer. On the example of the plate band, experimental studies supported by numerical analysis were carried out. The obtained research results and numerical analyses allowed for the formulation of a number of conclusions, mainly in terms of focusing on further research.
This article presents an experimental approach to fatigue testing of cableway gondolas, carried out in accordance with the EN 13796-3 standard. Due to the limitations of the aforementioned regulations and the lack of clarity in their content, when designing and conducting fatigue tests of gondolas, there is a need to find solutions that meet the normative requirements, while ensuring the cost-effectiveness of the tests. The work presents the method of loading, receiving the degrees of freedom, the methodology of gondola strength verification, and additional suggestions allowing for the satisfactory preparation of a plan of fatigue tests and their implementation. The paper shows problems and ways to solve it, what may occur during cableway gondolas fatigue test design. The research object is a 6-seater gondola designed by TRANSSYSTEM S.A. with its registered office in Wola Dalsza (Poland).
The work concerns the analysis of the possibilities of using light aircraft in the regional passenger transport. This analysis was based on the existing airport infrastructure in Poland. Between 43 existing airports with paved runways and length more than 1,000 meters potential routes of aircraft traffic were set. The study compared the light aircraft transport to the car transport. One of the benchmark criteria was the travel time between different destinations, using both means of transport. The second criterion is the financial aspects of travel. For this purpose, a statistics of light aircraft and calculated their Direct Operating Cost as a function of various parameters such as maximum weight, the number of passenger seats, cruise speed were created. Analysis also included air navigation charges on the routes and the operator profit. The calculations allowed identifying potential routes where the plane would be competitive with the car in terms of travel time and costs by one person. The number of these routes was dependent on the speed of travel, the number of seats on the plane as well as the fill factor of these seats. The analysis also applies to determine the number of passengers traveling between the regions. In 2013, domestic air transport handled less than 2.5 million passengers, which in comparison to the countries of Western Europe is a poor result. This is caused mainly by a small amount of domestic routes as well as a small number of regional airports. The implementation of the concept of using light aircraft in regional connections aims to increase the speed of travel, increase the safety in passenger transport, cost reduction and partial replacement of road transport by air transport.
This article presents an experimental approach to fatigue testing of cableway gondolas, carried out in accordance with the EN 13796-3 standard. Due to the limitations of the aforementioned regulations and the lack of clarity in their content, when designing and conducting fatigue tests of gondolas, there is a need to find solutions that meet the normative requirements, while ensuring the cost-effectiveness of the tests. The work presents the method of loading, receiving the degrees of freedom, the methodology of gondola strength verification and additional suggestions allowing for the satisfactory preparation of a plan of fatigue tests and their implementation. The paper shows problems and ways to solve it, what may occur during cableway gondolas fatigue test design. In addition, the work contains an extensive description and methodology for conducting research verifying the elastic and permanent deformation of the structure, using digital image correlation (DIC). The results obtained by using this method make it possible to unambiguously determine the degree of structure deformation while maintaining high accuracy and repeatability of measurements at many points of the structure. Following the presented tests, it was possible to correctly carry out fatigue tests of the nacelle in a satisfactory time (about 8 weeks), perform 5 million load cycles and verify the integrity of the structure. The presented results show the effectiveness of the adopted design assumptions and indicate the process that guarantees the correctness of the conducted fatigue tests. The prepared study may be the basis for further full-scale fatigue tests. The research object is a 6-seater gondola designed by TRANSSYSTEM S.A.
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