Wyniki wyszukiwania - BazTech

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Novel energy-absorbing auxetic sandwich panel with detached corrugated aluminium layers

Al-Rifaie Hasan

Vibrations in Physical Systems

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2023

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Vol. 34, nr 2

art. no. 2023215

EN

Sandwich panels have the potential to serve as plastically deforming sacrificial structures that can absorb blast or impact energies. Auxetic sandwich panels with welded or bolted corrugated layers have, as far as the author is aware, had their blast behaviour thoroughly addressed in the literature. Therefore, the objective of this numerical analysis was to create a novel, low-cost, simple-to-build graded sandwich panel with detached corrugated layers that may be employed as a multi-purpose sacrificial protective structure against a wide range of blast threats. The suggested sandwich panel has overall dimensions of 330x330x150mm and is made of six detached aluminium (AL6063-T4) layers enclosed in a steel (Weldox 460E) frame. With different stepwise plate thicknesses of 0.4, 0.8, and 1.2mm for each pair of layers, the six layers all have the same re-entrant auxetic geometry. Utilising the Abaqus/Explicit solver, the numerical analysis was carried out. A wide variety of blast intensities (4, 7, 11, 13, and 16 MPa peak reflected over-pressures) were tested on the suggested auxetic sandwich panel, and the results showed uniform progressive collapse, a superior decrease in reaction forces, and greater energy dissipation compared to comparable non-auxetic topologies. The innovative sandwich panel design has potential uses for both military and civic structures that need to be protected.

2

Global stability of an aluminum foam stand-alone energy absorber

Iluk A.

Archives of Civil and Mechanical Engineering

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2013

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Vol. 13, no. 2

137--143

EN

Aluminum alloy foam is the commonly used material in energy absorber design due to its excellent ability to dissipate energy in relation to density. This paper investigates the behavior of standalone absorber made of ALPORAS aluminum foam. The limiting parameters in the aforementioned application are the stability of absorber column and the risk of global buckling. Specimens with different slenderness ratio were crushed in order to find the transition point between local collapse of the cell walls and global buckling of the entire column. The ability of the aluminum foam energy absorber to work even after partial global buckling was presented.

3

Odpowiedź dynamiczna cienkościennych powłok stożkowych obciążonych impulsem ciśnienia

Jankowski J., Kubiak T.

Biuletyn Wojskowej Akademii Technicznej

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2011

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Vol. 60, nr 1

325-339

PL

W pracy zajęto się dynamiczną odpowiedzią cienkich powłok stożkowych poddanych impulsowemu obciążeniu ciśnieniem. Wymiary powłok są tak dobrane, aby mogły być stosowane jako pochłaniacze energii - panele stanowiące osłonę przeciwko fali uderzenia od wybuchu. Rozpatrzono również możliwość powstania zjawiska wyboczenia dynamicznego. Założono izotropowy materiał powłok (stal lub kompozyt) o charakterystyce biliniowej. Badano wpływ wstępnych imperfekcji kształtu na mechanizm zniszczenia. Analizy przeprowadzono, wykorzystując metodę elementów skończonych - program ANSYS 11.0.

EN

The paper deals with dynamic buckling phenomenon in aspect of response of open conical shells, subjected to pulse loading with pressure normal to the surface. Isotropic material of shells was assumed (steel or composite) with a bilinear characteristic. In this paper, influence of initial shape imperfection (corresponding to the least frequency of free vibration) on the mechanism of shell failure was investigated. Research was carried out with finite elements method using ANSYS 11.0 tool. Moreover, conical shells were analyzed as absorbers, in aspect of the change of pulse loading energy into energy of plastic deformations. To solve this problem, finite shell element (SHELL43 - 4 nodes with 6 degrees of freedom) was used. Investigated shells were simply supported at the lower edge. Moreover, initial shape imperfections were applied for amplitudes: 0, 0.2 g and g (where g - thickness of shell). Pulse loading function was assumed as triangular with amplitude of 1 MPa or 10 MPa. Calculations were divided into two parts. First, free vibration modes and frequencies were obtained. Next, the results were performed, applying appropriate modes, for the highest values of a total energy [J], total displacement [mm], reaction of the ground [N] and equivalent Huber stress [MPa], taking into account two different values of greater radius R. Concluding, analyzed conical shells have ability to dissipate loading energy. This process can be predicted and controlled by changing geometric parameters or/and level of initial shape imperfections. Mechanism of initial failure appears near spans.

4

Konstrukcje cienkościenne jako absorbery energii - najnowsze trendy i wyniki badań

Kotełko M., Lipa S.

Problemy Maszyn Roboczych

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2006

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Z. 28

33-43

PL

Praca ma charakter przeglądowy. Zawiera omówienie szeregu publikacji dotyczących szeroko pojętych zagadnień konstrukcji cienkościennych pracujących jako absorbery energii. Omawia podstawowe rozwiązania konstrukcyjne takich absorberów. Przedstawia wyniki badań autorów, dotyczące zastosowania krótkich, ściskanych profili cienkościennych jako absorberów energii, a także układów rur cienkościennych poddanych promieniowemu zgniotowi.

EN

The paper contains a review of several works carried out in the wide range of problems concerning thin-walled structures used as energy absorbers. Basic types of design of such structures are discussed. The results of works carried out by the authors are presented. The research was devoted to the investigation of the applicability of short thin-walled profiles as energy absorbers and also to the investigation into the crushing behaviour of thin-walled tube systems subject to lateral crushing load.

5

Konstrukcja i badania pochłaniacza energii z cieczą magnetoreologiczną

Myszkowski A., Sędziak D.

Zeszyty Naukowe Politechniki Poznańskiej. Budowa Maszyn i Zarządzanie Produkcją

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2004

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Nr 1

329-335

PL

W artykule omówiono konstrukcje pochłaniacza energii z cieczą magnetorcologiczną (MR). Przedstawiono wybrane wyniki badań doświadczalnych na stanowisku pomiarowym. Zastosowanie lego typu pochłaniaczy wraz odpowiednim układem sterującym pozwala kształtować i dostosować ich charakterystyki robocze do aktualnych warunków pracy maszyny.

EN

Unique properties of MR fluids offers a chance to design devices with controllable characteristics. In the paper construction of energy absorber with magnetorheological (MR) fluid was presented. Schemes of laboratory stand used during laboratory investigations was shown. Some chosen research characteristics was discussed. Such absorber can by controlled by a simple electronic regulator with a force and position feedback. This solution can reduce a danger vibration and noises on machines working under difficult and unstable conditions.