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Temperature Effect on Buckling Properties of Thin-Walled Composite Profile Subjected to Axial Compression

Falkowicz Katarzyna, Kuciej Michał, Święch Łukasz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

305--313

EN

This study investigates the influence of temperature variations on the buckling properties of thin-walled omega-profiles fabricated from carbon-epoxy composite materials. Utilizing a MTS testing machine, compression tests were conducted on these profiles at temperatures ranging from -20°C to 80°C, in 20°C increments. The primary objective was to assess how temperature fluctuations impact the buckling load and load-bearing capacity of these composite profiles under axial compression. The experimental setup allowed for precise measurement of load-displacement and load-deflection characteristics, and the critical load at which buckling initiation occurred. Observations revealed that the buckling resistance of the profiles exhibited a complex dependence on temperature. At lower temperatures, the composite material demonstrated enhanced stiffness and strength, marginally increasing buckling resistance. Conversely, at elevated temperatures, a noticeable degradation in mechanical properties was observed, leading to a reduced buckling load and altered failure modes. To complement the experimental findings, a comprehensive finite element (FE) analysis was conducted for sample in room temperature. The FE model, developed to replicate the experimental conditions closely, employed an eigenvalue-based approach to predict the buckling initiation and progression accurately. The presented results are the results of only preliminary tests and they will be expand about more samples number as well as to determine material properties for various temperatures.

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Experimental-Numerical Analysis of a Flat Plate Subjected to Shearing and Manufactured by Incremental Techniques

Kopecki Tomasz, Święch Łukasz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 4

179--188

EN

The paper presents the results of experimental studies and numerical analyses using the Finite Elements Method for a planar structure subjected to pure shear. The test specimen was made using an Fused Filament Fabrication incremental technique. In order to correctly represent the mechanical properties of the structure, a series of tests were performed to determine the physical constants of the model material used. Due to the perfect physical nature of the numerical model, in contrast to experimental phenomena, a suitable method was employed to induce the post-critical deformations in the analysed structure.

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Experimental Analysis of the Post-Buckling Behaviour of Compressed Stiffened Panel with Refill Friction Stir Spot Welded and Riveted Stringers

Kubit Andrzej, Święch Łukasz, Trzepiecinski Tomasz, Faes Koen

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 2

159--167

EN

The paper presents the results of research aimed at comparing two stringer joining technologies of stiffened panels. Experimental tests were carried out on the basis of uniaxial compression of thin-walled panels stiffened with two parallel stringers. The panels consist of a skin plate and stringers joined with two techniques: riveting and refill friction stir spot welding (RFSSW). The aim of the investigations was to determine the amount of the critical load, the character of the structure's work in the range of post-buckling behaviour and the mode of panel destruction. For deformation measurements, an optical scanner Aramis based on the digital image correlation (DIC) technique was used. The research conducted enabled the assessment of the effectiveness of the RFSSW technology of joining the semi-monocoque structures, taking into account the range of post-critical deformations caused both to the local and global loss of stability. The compression tests have shown that the plate with welded stringers with a spacing of 29.5 mm exhibits the ultimate load similar to the variant of the riveted panel. It was also observed that the nature and number of buckling half-waves depend on the applied load and spacing between connectors.

4

On the Identification of Local Structural Defects in Composite Thin-Walled Structures

Kopecki Henryk, Święch Łukasz, Kołodziejczyk Radosław

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 1

154--166

EN

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.