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1

The Effect of Energy Components Modifications on the Crashworthiness of Thin-Walled Structures

Rogala Michał, Gajewski Jakub

Advances in Science and Technology. Research Journal

|

2024

|

Vol. 18, no 6

110--120

EN

Thin-walled structures that serve as energy absorbers are widely used in the automotive industry, and it is well-known that they deform in a specific way under dynamic loading, forming plastic hinges along the yield line. The dynamic impact of these structures causes various phenomena that affect the formation of folds and, consequently, the dynamic response of the structure. The force-shortening curve, which is based on the unified crush efficiency indicators, is a key factor in determining the dynamic response of the structure. While there have been many studies on energy absorbers under static or quasi-static loading conditions, the effect of changing kinetic energy components (mass and velocity) on the obtained crush efficiency indicators is not as well understood. This article presents the results of experimental tests and nonlinear numerical simulations for eleven different initial conditions of the crashworthiness analysis. The tests showed a significant effect of changing the velocity and mass of the striker on the results obtained. Additionally, the nonlinear effect of the change in the velocity of the tup with respect to the peak force and total efficiency was demonstrated.

2

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

Falkowicz Katarzyna, Kulisz Monika

Advances in Science and Technology. Research Journal

|

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.

3

Numerical Analysis of Selected Variants of Reinforcements of Thin-Walled Open Load-Bearing Structures Subjected to Torsion

Kopecki Tomasz

Advances in Science and Technology. Research Journal

|

2024

|

Vol. 18, no 4

400--409

EN

The study concerns the comparative analysis of selected solutions of thin-walled structures subjected to constrained torsion, representing the simulation of wing areas weakened by large cutouts. The chosen variants of stiffening were based on the concept of so-called "Misztal torsion box", used in the wing of the PZL-37 aircraft. A series of numerical analyses were conducted, aiming to compare selected variants of structures with reinforcements and a reference structure based on a traditional design scheme. The calculations were performed using software based on the finite element method. An analysis of the stress and displacement distribution of the examined structure was conducted, and the results demonstrating the advantages of the proposed structural solution were presented.

4

Obrazowanie wad w strukturach cienkościennych z wykorzystaniem ultradźwiękowych fal prowadzonych

Spytek Jakub, Dziedziech Kajetan, Ambroziński Łukasz, Łukasz Pieczonka

Badania Nieniszczące i Diagnostyka

|

2023

|

nr 1-4

101--104

PL

W pracy przedstawiono nowatorską technikę badań nieniszczących struktur cienkościennych bazującą na estymacji lokalnej liczby falowej ultradźwiękowych fal prowadzonych. Technika bazuje na punktowym wzbudzeniu fal ultradźwiękowych i rejestracji odpowiedzi drganiowych na siatce punktów w obszarze zainteresowania z wykorzystaniem skanującego wibrometru laserowego. Wzbudzenie może być zrealizowane bezkontaktowo za pomocą impulsu lasera, bądź kontaktowo za pomocą przetwornika piezoelektrycznego. Praca omawia podstawy teoretyczne metody oraz jej zastosowania praktyczne. Skuteczność działania omawianej metody zilustrowano na przykładzie jednorodnej płyty aluminiowej oraz niejednorodnej warstwowej płyty kompozytowej.

EN

In this paper we present a novel nondestructive testing technique for platelike structures, using the local wavenumber estimation of ultrasonic guided waves. The technique is based on the excitation of ultrasonic waves and measuring the full-field response on a grid of points in the area of interest with a scanning laser vibrometer. The excitation can be realized using a non-contact laser pulse or a piezoelectric transducer. The paper discusses theoretical background of the technique and its practical applications. The efficacy of the proposed approach is demonstrated on a homogeneous aluminum plate and an inhomogeneous layered composite plate.

5

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

|

2023

|

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.

6

Numerical and Experimental Study of Crack Propagation in the Tensile Composite Plate with the Open Hole

Wysmulski Paweł

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no 4

249--261

EN

In this study, the thin-walled plate with the central open hole made of carbon-epoxy composite was investigated. The plate was tested in tension to investigate the mechanism of crack formation in the composite structure. The studies were carried out using two individual methods: experimental and numerical. In the experiment test, load was measured as the function of plate elongation. The Plate elongation was analysed using the Aramis optical non-contact measurement system. In the numerical study, the FEM model reproducing the experimental conditions was developed in the Abaqus software. The cracking process was modelled using the XFEM method (extended finite element method). This procedure allowed the of the composite to be examined over the full range of the tensile load. The behaviour of the plate with a circular open hole was investigated before damage symptoms and the damage initiation load was determined. The study continued to analyse the initial cracking and delamination of the laminate layers, together with crack propagation leading to cracking of all the laminate layers (complete failure of the composite structure). The novelty of this study is that it uses the popular XFEM method to describe the cracking and failure of the composite structure. In addition, the study proposes the novel method for determining the crack initiation and failure loads of the composite plate under tension, and the results obtained thereby are verified numerically.

7

Analysis of the Triggering Mechanism of the Square Thin-Walled Absorber

Rogala Michał, Gajewski Jakub

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no 6

206--216

EN

The aim of the research is the analysis of thin-walled aluminum profiles with embossed crush initiator. Samples with square cross-section loaded dynamically were studied until the complete loss of velocity by the tup. The numerical analyses were based on an elastic-plastic material model. The material properties of AA 6063 aluminum were derived from own tests performed on a tensile machine. The analyses were conducted using the numerical method (Abaqus CAE). Using a dynamic testing machine, the obtained numerical data were verified on the basis of models showing the best improvement in crush efficiency indicators. In the experimental study, high-speed camera images were used to identify the forming plastic hinges. Based on the obtained results of experimental and numerical analysis, crush efficiency indicators were determined and compared. It was determined that the use of a passive energy absorber increases the efficiency of the crushing force by around 50%, in addition, the correct location of the crush initiator allows to gain 15%. The results of the study showed that proper placement of the crush initiator decrease PCF while increasing MCF.

8

Crashworthiness and comparative analysis of polygonal single and bi-tubular structures under axial loading – experiments and FE modelling

Kannan I. Vimal, Rajkumar R.

Journal of Theoretical and Applied Mechanics

|

2021

|

Vol. 59 nr 1

81--94

EN

This article aims to present a report of experimental and numerical investigations on crashworthiness characteristics of single and multi-cell/bi-tubular structures. Novel multi--cell/bi-tubular structures are proposed in order to improve the crashworthiness performance, LS-DYNA FE software is applied for the modelling of axial crashing behaviour to validate with experimental results and a good agreement is observed. The KPIs are used to compare various structures and to determine the best performing ones. The investigations reveal that the HMC4 has significantly obvious effects on the structural crashworthiness and improved 515% energy absorption efficiency. Afterward, a parametric study has been carried out for the best energy absorber.

9

Static response of curved steel thin-walled box-girder bridge subjected to Indian railway loading

Verma V., Nallasivam K.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

|

Vol. 108, nr 2

63--74

EN

Purpose: The primary objective of the current study is to numerically model the steel thin-walled curved box-girder bridge and to examine its various response parameters subjected to Indian Railway loading. Design/methodology/approach: The analysis is conducted by adopting a one dimensional curved thin-walled box-beam finite beam element based on finite element methodology. The scope of the work includes a computationally efficient, three-noded, one-dimensional representation of a thin-walled box-girder bridge, which is especially desirable for its preliminary analysis and design phase, as well as a study of the static characteristics of a steel curved bridge, which is critical for interpreting its dynamic response. Findings: The analytical results computed using finite element based MATLAB coding are presented in the form of various stress resultants under the effect of various combinations of Indian Railway loads. Additionally, the variation in different response parameters due to changes in radius and span length has also been investigated. Research limitations/implications: The research is restricted to the initial design and analysis phase of box-girder bridge, where the wall thickness is small as compared to the cross-section dimensions. The current approach can be extended to future research using a different method, such as Extended finite element technique on curved bridges by varying boundary conditions and number of elements. Originality/value: The validation of the adopted finite element approach is done by solving a numerical problem, which is in excellent agreement with the previous research findings. Also, previous studies had aimed at thin-walled box girders that had been exposed to point loading, uniformly distributed loading, or highway truck loading, but no research had been done on railway loading. Moreover, no previous research had performed the static analysis on thin-walled box-girders with six different response parameters, as the current study has. Engineers will benefit greatly from the research as it will help them predict the static behaviour of the curved thin-walled girder bridge, as well as assess their free vibration and dynamic response analysis.

10

Zastosowanie cienkościennych konstrukcji integralnych w lotnictwie na przykładzie projektu SAT-AM

Bałon Paweł, Świątoniowski Andrzej, Rejman Edward, Kiełbasa Bartłomiej, Smusz Robert, Szostak Janusz, Kowalski Łukasz, Bałon Natalia, Cieślik Jacek

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

|

2020

|

z. 92 [300]

5--17

PL

Konstrukcje samolotów są poddawane w trakcie lotu działaniu różnych składowych stanu obciążenia. Każde zadanie w czasie lotu składa się z szeregu manewrów, które generują różne obciążenia samolotu, zarówno pod względem wartości, jak i kierunku ich działania. Wysoki poziom trwałości i niezawodności jest podstawowym, ścisłym wymogiem dla współczesnych konstrukcji lotniczych. Oznacza to, że podczas projektowania statku powietrznego należy wziąć pod uwagę wiele nierzadko sprzecznych ze sobą ograniczeń. Najważniejszym z nich jest masa konstrukcji, która ma decydujący wpływ zarówno na właściwości lotne i techniczne, jak i na ekonomikę eksploatacji. To sprawia, że samolot jest jednym z najbardziej złożonych produktów technicznych. Nowoczesne konstrukcje samolotów, a ściślej ich elementy nośne, są prawie wyłącznie wykonane jako cienkościenne, które spełniają postulat zminimalizowania masy konstrukcji. Szeroko rozpowszechnione są systemy, w których pokrycie jest wzmocnione elementami wzdłużnymi i poprzecznymi, zapewniając wymaganą sztywność i wytrzymałość całości systemu. Podczas gdy miejscowa utrata stateczności pokrycia jest dopuszczalna w warunkach obciążenia roboczego, przekroczenie poziomów obciążenia krytycznego elementów szkieletu konstrukcyjnego (ramy, podłużnice, wręgi) jest praktycznie równoznaczne ze zniszczeniem konstrukcji. Wskazane czynniki wymuszają ciągłe doskonalenie zarówno metod projektowania, jak i rozwiązań konstrukcyjnych w lotnictwie. Rozwój inżynierii materiałowej i ciągłe doskonalenie procesów technologicznych nie pozostają bez znaczenia dla skuteczności tych pomysłów. Dyscypliny te pozwalają konstruować geometrycznie złożone integralne struktury, które stwarzają możliwość nie tylko bardziej racjonalnego wykorzystania właściwości materiału, ale także, poprzez ich odpowiednie ukształtowanie, znacznie zwiększają dopuszczalne obciążenia konstrukcji nośnej. Główną zaletą przy projektowaniu części integralnych jest oszczędność ekonomiczna, uzyskana w wyniku wyeliminowania lub ograniczenia operacji montażowych. Gęsto żebrowane elementy pokrycia wykonane w tej technologii należą do elementów konstrukcji nośnej, które zmniejszają masę i podnoszą parametry wytrzymałościowe konstrukcji nośnej. Zmniejszając grubość pokrycia i jednocześnie wprowadzając gęsto usztywniające elementy podłużne, można uzyskać konstrukcję o znacznie wyższych obciążeniach krytycznych, a w konsekwencji bardziej korzystny rozkład gradientów i poziomów naprężeń, co bezpośrednio przyczynia się do zwiększenia trwałości zmęczeniowej. W artykule podjęto próbę oceny wprowadzenia nowych technologii wykonania konstrukcji płatowców dla podniesienia ich walorów wytrzymałościowych, aerodynamicznych oraz masowych.

11

Upper-bound estimation of load-carrying capacity of perforated cold-formed thin-walled steel lipped channel columns under compression loading

Kotelko Maria, Macdonald Martin, Kulatunga Muditha P., Marszalek Zuzanna

Eksploatacja i Niezawodność

|

2020

|

Vol. 22, no. 3

565--573

EN

Upper-bound estimation of the load-capacity of cold-formed steel sections (TWCFS) with perforations, subjected to axial compression is presented. The estimation is performed on the basis of the Yield Line Analysis ((YLA). TWCFS lipped channel sections with two sets of perforations (on the web and on the flanges) are under investigation. The comparison of experimental results, FE simulation results, European code ultimate strength predictions and upper-bound estimation based on YLA approach is carried out and presented. Some conclusions concerning an applicability of the YLA approach for ultimate strength prediction of perforated TWCFS structural members are derived.

PL

W artykule przedstawiono wyniki górnego oszacowania nośności cienkościennych prętów zimno formowanych z perforacjami, poddanych osiowemu ściskaniu. Oszacowanie to jest oparte na metodzie załomów plastycznych. Rozpatrywano dwa warianty perforacji (środnika i pasów) cienkościennych prętów ceowych z żebrami końcowymi. Przeprowadzono analizę porównawczą wyników eksperymentu, wyników symulacji numerycznych MES oraz wyników obliczeń wg wzorów normatywnych normy europejskiej z wynikami oszacowania górnego nośności opartego na metodzie załomów plastycznych. Sformułowano wnioski dotyczące możliwości zastosowania tej metody do szacowania nośności cienkościennych prętów zimno formowanych z perforacjami.

12

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

|

2020

|

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.

13

A comparative analysis of the load capacity of riveted and resistant welded joints

Lacki Piotr, Niemiro-Maźniak Judyta

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

|

2019

|

Z. 25 (175)

126-130

EN

There is a growing development in techniques that use thin-walled elements in construction and other industries, which is dictated primarily by the demand for lightweight, load-bearing structures, that are simple to manufacture and assemble. The paper presents selected methods of joining thin-walled metal structures. Experimental studies of the load capacity of resistance welded joints and riveted joints were carried out for the thickness of 0.8 mm. Graphs detailing the forces and displacements in the tested joints are shown and the method of sample destruction is presented. As a result of the tests, it was concluded that resistance welded joints achieved a load capacity of about 118% greater than the load capacity of riveted joints.

PL

W budownictwie oraz innych gałęziach przemysłu obserwuje się coraz większy rozwój technik stosowania elementów cienkościennych. Podyktowane jest to przede wszystkim zapotrzebowaniem na lekkie, a jednocześnie przenoszące odpowiednie obciążenia konstrukcje, z prostą technologią wytwarzania i montażem. W pracy przedstawiono wybrane sposoby łączenia cienkościennych konstrukcji metalowych. Przeprowadzono eksperymentalne badania nośności połączeń zgrzewanych oporowo oraz połączeń nitowanych. Statycznej próbie ścinania poddane zostały połączenia zakładkowe z pojedynczą zgrzeiną (nitem). Złącza wykonane zostały z blachy stalowej DCO1 o grubości 0,8 mm. Uzyskano wykresy sił i przemieszczeń dla badanych złączy oraz przedstawiono sposób niszczenia się próbek. W wyniku przeprowadzonych badań wywnioskowano, że złącza zgrzewane oporowo osiągnęły nośność o około 118% większą od nośności złączy nitowanych.

14

Diagnostic benchmarks on dynamic characteristics of thin-walled marine damaged structures

Szeleziński Adam, Murawski Lech, Muc Adam

Multidisciplinary Aspects of Production Engineering

|

2019

|

Vol. 2, Iss. 1

38--52

EN

Among structural health monitoring (SHM) methods of thin-walled structures, a vibrodiagnostic method is one of the most promising. The accelerometer recorded responses provide diagnostic information that requires mathematical processing to extract the essential dynamic characteristics. The authors have been looking for new parameters - diagnostic benchmarks which can be applied to non-destructive, automatic testing of thin-walled marine structures (especially their welded joints) like ship hulls. All characteristics have been based on recorded data generated during the vibration tests of welded joints with and without failures. For this purpose, the authors proposed method based on: FFT windowing analysis, benchmark with using 2D or 3D time – frequency dynamic characteristics and the determination of damping decrement in function of time. The work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds.

15

Design with SADSF method and analyses of elastic properties of torsion-loaded structures based on double-tee sections ‎

Markiewicz Ireneusz

Journal of Theoretical and Applied Mechanics

|

2019

|

Vol. 57 nr 1

115--126

EN

The paper presents results of the preliminary strength design using the method of statically admissible discontinuous stress fields (SADSF) of two new and interesting thin-walled structures based on double-tee sections. Although these constructions are intended to carry torsion moment loads, all their surfaces are accessible from outside. The paper is completed with the selected results of linearly-elastic FEM analyses of the presented solutions. They show surprisingly good strength properties and significantly higher load-carrying capacity comparing to structures designed in an intuitive way. The objectives of the paper, among other things, are as follows: popularization of the SADSF method, presentation of its new solutions and confirmation of practical usefulness in the design of thin-walled structures.

16

Design with SADSF method and analyses of elastic properties of torsion-loaded double-tee section with torsional box

Markiewicz I.

International Journal of Applied Mechanics and Engineering

|

2019

|

Vol. 24, no. 1

79--89

EN

The work presents the results of preliminary strength design of a thin-walled structure based on double-tee section loaded with a torsion moment. One of the solutions to this problem is considered, in which the torsional box is introduced in the central part. Then, one constructs a series of solution variants that differ in the torsional box length. In the design one uses the method of statically admissible discontinuous stress fields (SADSF) assuming the condition of equalized equivalent stress in the limit state. The work is complemented with elastic FEM analyses of one of the solution variants. Using this example, one shows good load-carrying properties of structures designed with the SADSF method, and proves that they could be several times better than the properties of structures designed with traditional or intuitive ways.

17

Numerical and experimental analysis of stability of thin-walled composite structures subjected to eccentric load

Debski Hubert

Archives of Civil and Mechanical Engineering

|

2019

|

Vol. 19, no. 3

792--802

EN

The study investigates the effect of eccentric load on the stability and post-critical states of thin-walled composite top-hat cross-section columns made of CFRP under compression. The specimens were subjected to compressive load on the universal testing machine Zwick Z100 with regard to both axial and eccentric compressive loads. On the basis of the experimental studies, numerical models of thin-walled composite profiles were designed and verified by numerical analysis based on the FEM. The first stage of the conducted studies was performing a linear buckling analysis of stability of composite structures. The second stage of the analysis involved performing a nonlinear analysis of the thin-walled structures with geometric imperfections reflecting the lowest buckling modes. The obtained test results showed various effects of non-axial compressive load on the critical load values and stiffness of the con- struction in the post-critical state. In the case of eccentric loading in the direction parallel to the web of the top-hat profiles, the critical load values practically did not change – a drop in the force did not exceed 1.5%, as well as there was no change in the stiffness of the structure in the post-critical state. The realization of the eccentricity in the direction perpendicular to the profile web caused a drop in the critical force equal 43% and a significant decrease in the stiffness of the structure. On the other hand, implementation of the eccentricity load toward the web caused an increase in the critical force by more than 20%, despite very small eccentricity values of only 4 mm were applied. This proved high sensitivity of the tested structures to the non-axial load in the direction perpendicular to the web of the profile. The FEM results and the experimental findings showed satisfactory agreement.

18

Numerical Crush Analysis of Thin-Walled Aluminium Columns with Square Cross-Section and a Partial Foam Filling

Ferdynus Mirosław, Rogala Michał

Advances in Science and Technology. Research Journal

|

2019

|

Vol. 13, no 3

144--151

EN

The article presents the results of numerical crush simulations of thin-walled structures with a square cross-section and partial filling with foamed material. The influence of the length of the filling on the values of the energy efficiency index was analysed. Four types of foamed material were subjected to numerical analysis. The research was conducted using FEM in Abaqus 6.14 program. The obtained results were presented in the following forms: load-shortening characteristics, tables and diagrams. The best energy absorbing properties are shown by models filled with aluminium and polyethylene terephthalate foam.

19

Experimental Research of the Weakening of the Fuselage Skin by RFSSW Single Row Joints

Kubit Andrzej, Bucior Magdalena, Kluz Rafał, Bochnowski Wojciech, Perłowski Ryszard

Advances in Science and Technology. Research Journal

|

2019

|

Vol. 13, no 3

90--97

EN

The paper presents the results of experimental investigations, the aim of which was to determine the degree of weakening of skin sheet of the thin-walled structure through a single-row welded joints made by Refill Friction Stir Spot Welding (RFSSW) technology. At the beginning, a short metallographic analysis of the weld was carried out, defining the characteristic areas of the microstructure. Then, comparative tests were carried out on the thin-walled structure sample in the form of a single-row skin-stringer joint. The structures made with the discussed technology of welding were compared with the traditionally joined structure by riveting. It has been shown that in the case of the welded structure, the skin sheet is weakened by more than 6% to a lesser extent than in the case of riveted. However, it was shown that the cracking path in the tensiled welded sheet runs along an unpredictable path, deviating from the line marked by the welds’ row. While in the case of riveted joint the cracking propagation along the row of rivets was revealed. The analyzes of fracture surfaces for both cases using scanning electron microscopy were also undertaken, thus undertaking preliminary considerations on the mechanism of fracture.

20

Strength properties of thin-walled structures designed with the sadsf method

Markiewicz J.

Journal of Machine Construction and Maintenance - Problemy Eksploatacji

|

2018

|

no. 4

113--122

EN

This study presents general conclusions resulting from elastic FEM analyses of several dozen of thin-walled structures designed with the use of the application version of the method of statically admissible discontinuous stress fields (SADSF). The conclusions are illustrated with examples of two original structures designed to work under torsional load. The structures are based on I-sections, whose all surfaces are accessible from outside. Despite that fact, torsional rigidity of the structures is very high. Additionally, in these structures, we examined the effects caused by modifications consisting in local stiffening of some elements by applying edge stiffeners on their borders.

PL

Praca przedstawia generalne wnioski z analiz sprężystych MES kilkudziesięciu konstrukcji cienkościennych, które zostały zaprojektowane z wykorzystaniem wersji aplikacyjnej metody statycznie dopuszczalnych nieciągłych pól naprężeń (SADSF). Otrzymane wnioski są prezentowane na przykładzie dwóch oryginalnych konstrukcji, które zostały zaprojektowane na obciążenie momentem skręcającym. Są to konstrukcje oparte na profilu dwuteowym, których wszystkie powierzchnie są z zewnątrz dostępne, a mimo to są bardzo sztywne na zakładany rodzaj obciążenia. Dla konstrukcji tych badano dodatkowo efekty powodowane poprzez wprowadzanie modyfikacji polegających na lokalnym usztywnieniu elementów poprzez odwijanie ich swobodnych krawędzi.