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1

Experimental Investigation on Axial Response of Composite Wood-Cold-Formed-Steel Fixed Ended Studs

Meddah Hiba, Bourahla Nouredine, Bechtoula Hakim, Aknouche Hassan

Inżynieria Mineralna

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2025

|

Vol. 2, no. 2

art. no. 50

EN

Compared to hot-rolled steel sections, cold-formed steel sections are more susceptible to instabilities. Under compressive loading, several global, distortional, and local buckling instability modes are expected to manifest. This paper summarizes results of an experimental program carried out at the National Center of Applied Research on Earthquake Engineering Laboratory (CGS) in ALGERIA to investigate the behavior up to failure of composite wood cold formed steel stud under cyclic axial loading, in which a wood core is incorporated inside the cold formed steel C stud subjected to axial cyclic loading which was compared with simple cold formed steel C stud. Six full scale columns with both ends fixed were tested, three cold formed steel C stud (600s200-68) and three with the same C sections reinforced with wood. Two monotonic axial concentric loading tests (one compression and one tension) and one cyclic axial loading test with different loading rate were performed on both cold-formed steel (CFS) columns and Wood CFS columns. The cyclic loading protocol was adapted from FEMA 461 with initial displacement obtained from the monotonic tests. The results showed that the local deformations (local buckling) were less noticeable for the wood CFS columns. It was also observed that, the degradation of resistance, rigidity and the total hysteretic energy dissipated were more important for composite columns.

2

A simple quasi-3D theory for static stability analysis of imperfect FG beam

Menasria A., Slimani R., Bouhadra A., Refrafi S., Chitour M., Ali Rachedi M., Himeur N., Zerari K.

Archives of Mechanics

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2025

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Vol. 77, nr 3

263--287

EN

This study introduces a simplified approach to assess the buckling and static bending of advanced composite beams, including those composed of functionally graded materials (FGMs) with various porosity models. The technique utilizes a straightforward integral quasi-3D approach based on the advanced shear deformation theory. This approach offers several advantages: it simplifies the analysis by reducing the number of unknowns and equations required, improves accuracy by considering the stretch effect across the entire depth of the beam, resulting in more reliable results, and accurately represents shear by satisfying the zero-traction boundary conditions on the beam’s surfaces without the need for a shear correction factor. Additionally, it captures the parabolic pattern of transverse shear strain and stress throughout the depth of the beam. The governing equations are obtained by applying the concept of virtual work, and the Navier solution is employed to calculate analytical solutions for the buckling and static bending of FGM porous beams under different boundary conditions. The approach is in line with and builds upon existing research on FGMs and other sophisticated composite beams, further enhancing its validity and reliability. Finally, computational analyses demonstrate how the distribution of materials, such as power-law functionally graded materials (FGMs), geometry, and porosity, affect the deflections, stresses, and critical buckling load of the beam.

3

Buckling of a structure made of a new eco-composite material

Gawryluk Jarosław, Głogowska Karolina, Bartnicki Hubert

Applied Computer Science

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2025

|

Vol. 21, no. 2

28--36

EN

This paper reports the experimental results of a study investigating a new eco-composite material made from 100% recycled material. Tensile and density tests were conducted. A numerical model of a one-sided fixed beam was designed by the finite element method and a buckling analysis of this structure was performed. Three different cross-sections and lengths of the beam were tested. The first fundamental buckling mode and the corresponding critical load value were determined. The obtained numerical results were verified by analytical method using Euler's formula, which showed high agreement between the results. The relative error was less than 4%. A higher level of agreement was obtained for longer beams than for shorter ones. The results obtained for the eco-composite were then compared with those reported for other materials with similar properties, namely LDPE, HDPE and PP. Compared to LDPE and HDPE, the eco-composite showed higher stiffness parameters and load resistance, which made the tested structure more rigid and therefore stable for a longer period of time. The analysis of beams with different crosssections and lengths made it possible to determine the effect of these parameters on the critical load, providing valuable insights for designers. It was observed that a 100% increase in the initial rectangular cross-section of 800mm2 resulted in a 685% increase in the stiffness of the beam. A 100% increase in the initial beam length of 150mm resulted in a 75% decrease in the critical force. The results of this study have confirmed that the new eco-composite material can be effectively used in engineering structures.

4

The fatigue strength of thin-walled shell structures with cutouts, in post-critical deformation states

Mazurek Przemysław

Advances in Science and Technology. Research Journal

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2025

|

Vol. 19, no. 11

149--161

EN

The study presents the results of research on thin-walled elements made of aluminum alloy, subjected to pure shear. These elements represent a representative section of the skin of a semi-monocoque aircraft structure, weakened by an inspection hole. The possibility of the occurrence of post-critical deformations under operational load conditions was considered. The results of a numerical analysis conducted under static load conditions using the finite element method are presented. Based on the obtained stress distribution, a fatigue strength simulation was performed, based on the ε-n analysis. The results were verified using experimental static and fatigue tests.

5

Formulation of the critical lateral buckling moment of a steel I-beam

Derlatka Anna, Gao Shan

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2024

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Z. 30 (180)

23--28

EN

The paper presents an analysis of the method of formulation of the critical lateral moment during buckling of an I-beam. Three methods of determining the critical moment were considered: commonly known analytical formulas, the Robot Structural Analysis Professional 2024 program and the finite element method implemented in the ADINA program. The subject of the analysis was the steel beam with a cross-section of IPE 200. Two simply supported beams were considered. The first one was loaded with a concentrated force and the second one was loaded with an evenly distributed load.

PL

Przedstawiono analizę sposobu obliczania momentu krytycznego przy zwichrzeniu belki dwuteowej. Rozważano trzy sposoby wyznaczania momentu krytycznego: powszechnie znane wzory analityczne, program Robot Structural Analysis Professional 2024 oraz metodę elementów skończonych zaimplementowaną w programie ADINA. Przedmiotem analizy była belka stalowa o przekroju IPE 200. Rozważano dwie belki swobodnie podparte. Pierwszą obciążono siłą skupioną, a drugą obciążono obciążeniem równomiernie rozłożonym.

6

Praktyczne aspekty wymiarowania ściskanych pasów dźwigarów kratowych sztywno połączonych ze słupami wg PN-EN 1993-1-1 na przykładzie hali dwunawowej

Drzazga Marek

Przegląd Budowlany

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2024

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R. 95, nr 3

44--49

PL

Norma PN-EN 1993-1-1 daje możliwość sprawdzania nośności granicznej (ULS) stalowych elementów ściskanych na kilka sposobów. W artykule przedstawiono praktyczne podejścia do wymiarowania ściskanych pasów kratownic z uwzględnieniem stateczności z płaszczyzny układu. Przeanalizowano rzeczywistą kratownicę dachową konstrukcji stalowej w hali dwunawowej, z pośrednimi stężeniami sztywnymi. Wykonano analizę porównawczą metod klasycznych i bardziej zaawansowanych z uwzględnieniem ograniczeń danych metod oraz oceną ich pracochłonności i korzyści przy projektowaniu ściskanych pasów kratownic sztywno połączonych ze słupami. Opisane zaawansowane metody obliczeń pozwalają uwzględnić różne realne konfiguracje wstępnie zdeformowanej konstrukcji, prowadząc do optymalnego projektowania konstrukcji obiektów halowych lub umożliwiają szukanie zapasów nośności konstrukcji przy zmianie wielkości lub układu obciążeń.

EN

The PN-EN 1993-1-1 standard provides possibility to check ultimate limit states (ULS) of compressed steel elements in several ways. This paper describes practical approaches to design compressed truss chords taking into account out-of-plane stability. The real roof truss of a steel structure in the two-aisle hall with intermediate rigid braces was analyzed. A comparative analysis of classic and more advanced method was performed taking into account the limitations of the given methods and the assessment of their labor consumption and benefits when designing compressed truss chords rigidly connected to columns. The advanced calculation methods make it possible to take into account various real configurations of a pre-deformed structure, leading to optimal design of hall structures or enabling the search for reserves of the structure’s load-bearing capacity when changing the value or arrangement of loads.

7

Elastic buckling of a rectangular sandwich plate with an individual functionally graded core

Magnucki Krzysztof, Magnucka-Blandzi Ewa, Sowiński Krzysztof

Journal of Theoretical and Applied Mechanics

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2024

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Vol. 62 nr 1

171--185

EN

This paper is devoted to a thin-walled sandwich plate with an individual functionally graded core. The nonlinear shear deformation theory of a straight normal line is applied. A system of three differential equations of equilibrium of this plate is obtained, based on the principle of stationary potential energy, which is reduced to two differential equations and solved analytically. The critical load of the rectangular sandwich plate is determined. A detailed analytical study is carried out for selected exemplary plates. Moreover, a numerical FEM model of this plate is developed. The results of these calculations are compared with each other.

8

Buckling and bending analysis of porous fg beam using a simple integral QUASI-3D theory

Himeur Nabil, Menasria Abderrahmane, Bouhadra Abdelhakim, Mourad Chitour, Refrafi Salah, Guessoum Loubna, Ouchene Aya, Lebouazda Salima

Journal of Applied Mathematics and Computational Mechanics

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2024

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Vol. 23, nr 4

30--41

EN

This paper introduces a simplified approach to analyze the buckling and static bending of advanced composite beams, including functionally graded materials (FGMs), with various porosity distributions. This method uses a simple integral quasi-3D approach with a higher-order shear deformation theory, which offers several advantages: reduced complexity by requiring fewer unknowns and governing equations compared to other methods; improved accuracy by incorporating the effect of stretching across the beam’s thickness, leading to more accurate results; finally, accurate shear representation by satisfying the zero-traction boundary conditions on the beam’s surfaces without needing a shear correction factor; and it captures the parabolic distribution of the transverse shear strain and stress across the thickness. The virtual work principle is used to derive the governing equations, and the Navier solution is employed to find analytical solutions for buckling and static bending of various boundary conditions for FGM porous beams. The proposed method agrees well with the literature on FGMs and other advanced composite beams. Finally, numerical results showcase how material distribution (including power-law FGMs), geometry, and porosity affect the beam’s deflections, stresses, and critical buckling load.

9

Nowoczesne narzędzia w projektowaniu kopuł stalowych

Studziński Robert, Ordziniak Paweł

Inżynieria i Budownictwo

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2024

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R. 80, nr 7

473--477

PL

W artykule omówiono nowoczesne metody numeryczne, które mogą być stosowane w analizie statycznej i wytrzymałościowej kopuł stalowych. Przeanalizowano przykład stalowej kopuły żebrowej, dla której obciążenie wiatrem zostało wygenerowane przy użyciu analizy CFD w tzw. numerycznym tunelu aerodynamicznym. Ponadto zaprezentowano sposób implementacji imperfekcji, uzyskanych z liniowej analizy wyboczeniowej, do modelu statycznego, zgodnie z wytycznymi Eurokodu 3.

EN

The article discusses modern numerical methods that can be applied in the static and strength analysis of steel domes. A case study of a steel ribbed dome is analyzed, where wind load was generated using CFD analysis in a so-called numerical wind tunnel. Additionally, a method for implementing imperfections obtained from linear buckling analysis into the static model, in accordance with the guidelines of Eurocode 3, is presented.

10

Buckling and free flexural vibration of an asymmetric sandwich beam with a functionally graded core

Magnucki K., Magnucka-Blandzi E., Sowiński K.

Archives of Mechanics

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2024

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Vol. 76, nr 4

335--355

EN

This paper is devoted to an asymmetrical sandwich beam with a functionally graded core with three different variants of boundary conditions. An analytical model of this beam, considering individual nonlinear shear deformation theory, is developed. Based on Hamilton’s principle, two differential equations of motion for this beam are obtained. These equations are solved analytically, and as a consequence, the critical forces and basic natural frequencies for each beam support variant are determined. Detailed calculations are carried out for selected exemplary beam structures, and their results are compared with numerical FEM analysis.

11

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

|

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.

12

Stability of Thin-Walled Composite Structures with Closed Sections Under Compression

Rosłaniec Kuba, Różyło Patryk

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 3

188--199

EN

The purpose of the research was to analyze the experimental-numerical influence of the type of cross-section on the stability of thin-walled composite columns with closed (rectangular) cross-sections. The subject of the investigation was thin-walled composite structures made of CFRP composite (carbon fiber reinforced polimer), characterized by a closed rectangular cross-section shape of the profile and a identical ply configuration. In this study, experimental and numerical investigations of axially compressed columns were performed to determine the values of buckling loads and buckling forms. Experimental investigations were performed using a universal testing machine with an optical deformation measurement system. In parallel with the experimental tests, numerical simulations were made using the FEM (Finite Element Method). The numerical studies conducted using dedicated numerical models and the experimental studies made it possible to carry out a thorough analysis of the impact of the cross-sectional shape on the buckling phenomenon of the structure. The novelty of the present paper is the use of interdisciplinary testing methods to compare the effect of cross-sectional geometry on the stability of thin-walled composite columns.

13

Prediction of Buckling Behaviour of Composite Plate Element Using Artificial Neural Networks

Falkowicz Katarzyna, Kulisz Monika

Advances in Science and Technology. Research Journal

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2024

|

Vol. 18, no. 1

231--243

EN

This article presents the use of Artificial Neural Networks (ANNs) to analysis of the composite plate elements with cut-outs which can work as a spring element. The analysis were based on results from numerical approach. ANNs models have been developed utilizing the obtained numerical data to predict the composite plate’s flexural-torsional form of buckling as natural form for different cut-outs and angels configurations. The ANNs models were trained and tested using a large dataset, and their accuracy is evaluated using various statistical measures. The developed ANNs models demonstrated high accuracy in predicting the critical force and buckling form of thin-walled plates with different cut-out and fiber angels configurations under compression. The combination of numerical analyses with ANNs models provides a practical and efficient solution for evaluating the stability behaviour of composite plates with cut-outs, which can be useful for design optimization and structural monitoring in engineering applications.

14

Influence of Size of Open Hole on Stability of Compressed Plate Made of Carbon Fiber Reinforced Polymer

Wysmulski Paweł, Mieczkowski Grzegorz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 2

238--247

EN

This manuscript concerns the investigation of the influence of the open hole on stability of the compression plate made of carbon-epoxy composite. Experimental tests carried out on the real plate resulted in a postcritical path from which the critical load value was determined using appropriate approximation method. In parallel, an independent study was carried out based on a numerical analysis using the finite element method (FEM). Investigations were conducted in terms of a linear eigenproblem analysis, from which the value of the bifurcation load was determined for the FEM model of the plate. Its values resulting from the numerical analyses were validated against the experimental results, thus confirming the adequacy of the designed FEM model of the plate. The paper shows that the incremental increase of the hole in the plate monotonically influences the decrease in the critical load of the plate. The largest decrease was observed for the specimen with the largest hole analysed and was 13.5% compared to a plate without a hole. The newness of the paper is the application of interdisciplinary investigation methods to describe the influence of the open hole compression (OHC) on the stability of composite plates. ABAQUS® was used as the tool with which the numerical analyses were realised.

15

Second-order effects in horizontally loaded reinforced concrete columns

Pędziwiatr Janusz, Musiał Michał

Studia Geotechnica et Mechanica

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2023

|

Vol. 45, nr 4

417--429

EN

This paper deals with the second-order effects in horizontally loaded reinforced concrete columns. The current standard approach according to Eurocode 2 is the starting point for the considerations. Simplified methods that take into account the secondary effects, that is, the nominal stiffness method and the nominal curvature method, and their limitations are discussed. Most attention is devoted to the general method. As only general guidelines for this method can be found in the literature on the subject, the author presents his own original approach to calculations done using this method. Exemplary analyses for the corbel columns of high bay racked warehouses are made. Columns of different lengths are analyzed. The calculations show the overestimates introduced by the simplified methods and the benefits stemming from the use of the general method, especially in the case of quite slender columns.

16

Buckling and vibration of porous sigmoid functionally graded conical shells

Huang Xiaolin, Wang Jiaheng, Wei Nengguo, Wang Chengzhe, Ma Bin

Journal of Theoretical and Applied Mechanics

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2023

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Vol. 61 nr 3

559--571

EN

In this study, the buckling and vibration of a sigmoid functionally graded material (S-FGM) shells are investigated. Two types of porosity distributions, even and uneven, are taken into account. The material properties are estimated by a new modified rule of mixture. In the framework of the classic thin shell theory, the governing equations are derived and Galerkin’s integrate technique is employed to compute the critical load and natural frequency of porous S-FGM shells. The influence of pores, ceramic mass fraction and materials power index are discussed in detail.

17

Calculation of second-order effects in columns - applications and examples

Pędziwiatr Janusz, Musiał Michał

Archives of Civil Engineering

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2023

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Vol. 69, nr 1

271--286

EN

Standard PN-EN 1992-1-1 for designing reinforced concrete structures gives a major priority to the issues relating to second-order effects, but presents in detail only two approximate calculation methods: the nominal stiffness method and the nominal curvature method. As regards the general method, only certain requirements and suggestions are provided. In typical situations, when the appropriate assumptions are satisfied, the approximate methods yield satisfactory results. However, in engineering practice one can come across several cases (e.g. very tall columns, columns with a cantilever for a gantry girder, and floor joists) in which the approximate methods will prove unreliable. This paper presents and discusses a procedural algorithm for analysing second-order effects using the general method. The algorithm is employed to perform exemplary calculations and their results are compared with the results yielded by the approximate methods commonly used by engineers. Moreover, areas in which the approximate methods can be unreliable are indicated. The analyses have confirmed the significant advantage of the general method over the approximate methods. Therefore it is worth popularizing this method, the more so that its calculation procedures can be to a large extent automated and dedicated computer programs can be developed.

PL

W aktualnej normie do projektowania konstrukcji żelbetowych PN-EN 1992-1-1 problemom związanym z efektami drugiego rzędu nadano znaczącą rangę, ale ograniczono się do szczegółowego omówienia jedynie dwóch przybliżonych metod obliczeniowych - nominalnej sztywności i nominalnej krzywizny. W odniesieniu do metody ogólnej przedstawiono jedynie pewne wymagania i sugestie. W typowych sytuacjach, gdy spełnione są odpowiednie założenia, metody przybliżone dają zadawalające rezultaty. W praktyce inżynierskiej można jednak napotkać szereg przypadków, w których metody przybliżone będą zawodne - np. bardzo wysokie słupy i słupy ze wspornikami pod belki podsuwnicowe lub belki stropowe. W artykule przedstawiono i omówiono algorytm postępowania dla analizy problemu metodą ogólną. Według tego algorytmu wykonano przykładowe obliczenia a ich rezultaty porównano z rezultatami uzyskanymi z wykorzystaniem powszechnie stosowanych przez inżynierów metod przybliżonych. Wskazano ponadto obszary, w których metody przybliżone mogą zawodzić. Przeprowadzone analizy potwierdziły istotną przewagę metody ogólnej nad przybliżonymi. Warto ją propagować, tym bardziej że można jej procedury obliczeniowe zautomatyzować i opracować programy komputerowe.

18

Stability of the thin-walled angle column made of bio-laminate versus glass-laminate under axial compression – numerical study

Gawryluk Jarosław

Archive of Mechanical Engineering

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2023

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LXX, nr 1

43--61

EN

The aim of this study was to determine how the change of glass laminate fibres to flax fibres will affect the stability of thin-walled angle columns. Numerical analyses were conducted by the finite element method. Short L-shaped columns with different configurations of reinforcing fibres and geometric parameters were tested. The axially compressed structures were simply supported on both ends. The lowest two bifurcation loads and their corresponding eigenmodes were determined. Several configurations of unidirectional fibre arrangement were tested. Moreover, the influence of a flange width change by ±100% and a column length change by ±33% on the bifurcation load of the compressed structure was determined. It was found that glass laminate could be successfully replaced with a bio-laminate with flax fibres. Similar results were obtained for both materials. For the same configuration of fibre arrangement, the flax laminate showed a lower sensitivity to the change in flange width than the glass material. However, the flax laminate column showed a greater sensitivity to changes in length than the glass laminate one. In a follow-up study, selected configurations will be tested experimentally.

19

Buckling of Compressed Thin-Walled Composite Structures with Closed Sections

Różyło Patryk, Rosłaniec Kuba, Kuciej Michał

Advances in Science and Technology. Research Journal

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2023

|

Vol. 17, no. 6

63--72

EN

The subject of the study was thin-walled composite structures, which were made of carbon-epoxy composite. The structures were characterized by a closed square cross-sectional shape. In the research paper, stability tests of axially compressed thin-walled composite structures were carried out in order to determine the critical state of the structures. Experimental tests were carried out on a universal testing machine, using a system for optical measurement of deformation of structures. Numerical simulations were carried out using the finite element method. The research made it possible to evaluate the work of the structure in the buckling state from a qualitative and quantitative point of view.

20

Analysis of Thin-Walled Elements, with Ribbed Stiffeners, in the State of Post-Critical Deformations

Mazurek Przemysław

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no. 4

61--69

EN

The paper presents the results of research on fragments of thin-walled coverings made of aluminum alloy. The exmined structures were subjected to shear stresses leading to post-critical deformations. Three types of elements were analyzed: an element without stiffeners (the referencial one), an element with three stiffening ribs and an element with five stiffening ribs. The results of numerical analyzes and static experimental research were presented. Althought this kind of solutions is commonly used in various aircraft structures, the publications about it are usually hard to rich. The research concerning ribbed stiffeners are usually performed inside laboratories of aerospace concerns and their results are not published in the open sources. The general direction of analyses of this solution is indicated in presented study.