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1
Content available 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.
2
Content available Obrazowanie wad w strukturach cienkościennych z wykorzystaniem ultradźwiękowych fal prowadzonych
Spytek Jakub, Dziedziech Kajetan, Ambroziński Łukasz, Pieczonka Łukasz
Badania Nieniszczące i Diagnostyka
|
2022
|
1-4
93--96
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.
3
Content available 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.
4
Content available FEM and experimental analysis of thin-walled composite elements under compression
Różyło P., Wysmulski P., Falkowicz K.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 2
393--402
EN
Thin-walled steel elements in the form of openwork columns with variable geometrical parameters of holes were studied. The samples of thin-walled composite columns were modelled numerically. They were subjected to axial compression to examine their behavior in the critical and post-critical state. The numerical models were articulately supported on the upper and lower edges of the cross-section of the profiles. The numerical analysis was conducted only with respect to the non-linear stability of the structure. The FEM analysis was performed until the material achieved its yield stress. This was done to force the loss of stability by the structures. The numerical analysis was performed using the ABAQUS® software. The numerical analysis was performed only for the elastic range to ensure the operating stability of the tested thin-walled structures.
5
Content available Modal Analysis of Laminated “CAS” and “CUS” Box-Beams
Gawryluk J., Bocheński M., Teter A.
Archive of Mechanical Engineering
|
2017
|
Vol. LXIV, nr 4
441--454
EN
In the paper, the authors discuss the numerical and experimental modal analysis of the cantilever thin-walled beams made of a carbon-epoxy laminate. Two types of beams were considered: circumferentially asymmetric stiffness (i.e., CAS) and circumferentially uniform stiffness (i.e., CUS) beams. The layer-up configurations of the laminate were chosen to get a vibration mode coupling effect in both analysed cases. The aim of the paper was to perform the numerical and experimental modal analysis of the composite structures, when a flapwise bending with torsion coupling effect or flapwise-chordwise bending coupling effect took place. Firstly, numerical studies by the finite element method was performed. The numerical simulations were carried out by the Lanczos method in the Abaqus software package. The natural frequencies and the corresponding free vibration modes were determined. Next, the experimental modal analyses of the CAS and CUS beams were performed. The test stand was consisted of a special grip, two beams with an adhered holder, the LMS Scadas III system with a modal hammer and an acceleration sensor. Finally, the results of both methods were compared.
6
Content available Effect of quadrilateral discontinuity size on the energy absorption of structural steel profiles
Estrada Q., Szwedowicz D., Majewski T., Martinez E., Rodriguez-Mendez A.
Eksploatacja i Niezawodność
|
2016
|
Vol. 18, no. 2
186--193
EN
In this paper the effect of discontinuity size on energy absorption performance of steel square profiles is reported. The analysis consists of finite element simulations and experimental results of the compression strength of steel profiles with discontinuities. The discontinuities were placed at the mid span of the profiles in two walls opposite to each other. Square, rectangular and diamond initiators were evaluated at different scales. The numerical results determined the size intervals that present a good energy absorption performance in each case. Energy absorption capabilities were increased up to 12.54% with respect to a structure without discontinuities. Additionally, the peak load value (Pmax) was decreased 25.97% with the implementation of a diamond initiator. For structures with discontinuities with major axis close to the profile width, a buckling effect was observed. Finally, it was observed that the size of the initiators contributes to reduce the peak load (Pmax) value.
PL
W pracy przedstawiono analizę wpływu rozmiaru nieciągłości na pochłanianie energii przez stalowe profile o przekroju kwadratowym. Analiza przedstawia wyniki symulacji elementami skończonymi próby ściskania profili stalowych z nieciągłościami oraz porównanie z danymi eksperymentalnymi. Nieciągłości zostały usytuowane w środku profilu w dwóch przeciwległych ścianach. W pracy zostały przebadane nieciągłości o formach kwadratowych, prostokątnych i rombowych dla różnych wymiarów. Stwierdzono wzrost o 12,54% możliwości pochłaniania energii w porównaniu dla struktur bez nieciągłości. Dodatkowo, w przypadku nieciągłości rombowych stwierdzono spadek wartości siły maksymalnej (Pmax) o 25,97%. Zaobserwowano występowanie efektu wyboczenia dla nieciągłości rombowej gdy wymiar jej osi zbliża się do szerokości profilu. Zaobserwowano, ze rozmiar nieciągłości wpływa na redukcje wartości maksymalnego obciążenia oraz w tym samym czasie na obniżenie pochłanianej energii.
7
Analiza procesu odkształcenia cienkościennych belek skrzynkowych, łączonych różnymi metodami, pod wpływem trójpunktowego zginania
Sadowski T., Nowicki M., Pietras D., Golewski P.
Rudy i Metale Nieżelazne Recykling
|
2015
|
R. 60, nr 12
694--699
PL
Przedstawiona praca zawiera wyniki badań laboratoryjnych oraz analiz numerycznych trójpunktowego zginania aluminiowych belek skrzynkowych. Analizowane elementy, o przekroju poprzecznym omega zostały połączone na kilka różnych sposobów z płaskimi płytkami tworząc przekroje zamknięte. Łączniki j akie zostały tu u żyte to k leje z g rupy L octite o raz nity zrywalne o średnicy 4 mm, a także kombinacje tych połączeń. Belki o wymiarach 84 × 36 × 300 mm poddano quasi statycznemu obciążeniu w dwóch położeniach: profil omega w górnej lub dolnej pozycji. Dla każdej z tych pozycji wykonano taką samą liczbę analiz i testów. Ponadto praca zawiera wyniki analiz numerycznych dla profili jednolitych. Przedstawione wyniki prezentują charakter odkształcenia profilu w zależności od jego położenia względem obciążenia oraz od rodzaju użytego łącznika. Można tu także wyraźnie zaobserwować rozkłady naprężeń w elementach oraz poziom delaminacji łączonych warstw w różnych przypadkach obciążenia.
EN
This paper presents results of laboratory tests and numerical analyzes of three-point bending of aluminum box beams. The analyzed omega profiles are combined in different ways with the flat plates to form a closed profile. Various combinations of made of Loctite adhesives and rivets having a diameter of 4 mm were applied to get different types of connections. Specimens of dimensions 84 × 36 × 300 mm were subjected to quasi-static loading in two positions: omega profile on the top or bottom position. The experimental tests were modeled numerically with application of the ABAQUS program. Moreover, the work contains also numerical analyzes of uniform profiles made of pure aluminium material. The results represent modes of the deformation profile, depending on its position relative to load and on type of connectors. Distributions of stresses in the elements and the level of delamination of the adhesive layers combined in various cases of the thinwalled box beams were presented.
8
Content available remote Numerical Representation of Bifurcation in the Process of Determining Stress Distributions in Post-Critical Deformation States of Aviation Load-Bearing Structures
Chodorowska D., Kopecki T., Mazurek P.
Mechanics and Mechanical Engineering
|
2013
|
Vol. 17, nr 1
17--27
EN
The study presents the results of research on the problem of obtaining credible results of nonlinear FEM analyses of thin-walled load-bearing structures subjected to post-critical loads. The similarity of numerical simulations results and actual stress distributions state depends on the correct numerical reproduction of bifurcations that occur during advanced deformations process.
9
Content available Experimental investigation of post-buckling behavior of composite column with top-hat cross-section
Dębski H.
Eksploatacja i Niezawodność
|
2013
|
Vol. 15, no. 2
106-110
EN
The object of this study is a thin-walled beam made of carbon-epoxy composite with open cross-section. The material used was a composite of epoxy matrix reinforced with carbon fiber (system HexPly M12, Hexcel). The M12 system is used above all in aircraft structures. It exhibits high fatigue durability and good maintenance properties at relatively low specific gravity. The research was lead as the FEM numerical analyses and experimental tests in buckling and post-buckling state, as well. In the conducted research in order to evaluate the effort ratio of the composite the Tsai-Wu tensor criterion was exploited. The numerical tool used was the ABAQUS software.
PL
Przedmiotem badań jest cienkościenna belka wykonana z kompozytu węglowo-epoksydowego o przekroju otwartym. Zastosowanym materiałem był kompozyt o osnowie żywicy epoksydowej wzmacniany włóknami węglowymi systemu HexPly M12 (Hexcel). System M12 wykorzystywany jest w przede wszystkim w strukturach lotniczych i charakteryzuje się wysoką trwałością zmęczeniową oraz dobrymi właściwościami eksploatacyjnymi, przy stosunkowo niskim ciężarze własnym. Badania prowadzono w zakresie obliczeń numerycznych z wykorzystaniem MES oraz badań eksperymentalnych w stanie krytycznym i pokrytycznym. W prowadzonych badaniach do oceny stopnia wytężenia kompozytu wykorzystano kryterium tensorowe Tsai-Wu. Zastosowanym narzędziem numerycznym był program ABAQUS.
10
Content available remote Theoretical and experimental study on the flattening deformation of the rectangular brazen and aluminum columns
Niknejad A., Elahi S. M., Elahi S. A., Elahi S. A.
Archives of Civil and Mechanical Engineering
|
2013
|
Vol. 13, no. 4
449--464
EN
This paper presents a theoretical and experimental study on lateral compression of square and rectangular metal columns. Some theoretical relations are derived to predict the absorbed energy, the specific absorbed energy and the instantaneous lateral load during the lateral compression. Analytical relations are obtained in two stages: elastic and plastic parts. In the plastic zone, the total absorbed energy by the column is calculated, based on the energy method. Then, an analytical equation is derived to predict the instantaneous lateral load. In the elastic part, the instantaneous load is obtained by linear behavior assumption. To verify the theoretical formulas, some lateral compression tests were carried out on square and rectangular columns and the experimental results are compared with the theoretical predictions, which shows a good agreement. Also, based on the experiments, effects of geometrical dimensions and material properties of the columns on the energy absorption capability are investigated. The results show that the absorbed energy by a column increases proportional to the column length. Also, columns with the thicker wall have the higher specific absorbed energy and so, rectangular columns with the thicker wall are the better energy absorbers during the flattening process. Also, the absorbed energy increases when the length of the column edge along which the load is applied decreases. Also, it is found that the specific absorbed energy by the aluminum columns is higher than the brazen ones and therefore, flattened columns with the high ratio of the flow stress/density are the better energy absorbers.
11
Content available remote Approximate BEM analysis of time-harmonic magnetic field nearby current-lines in thin shield
Jabłoński P.
Przegląd Elektrotechniczny
|
2012
|
R. 88, nr 12b
61-63
EN
This paper focuses on a possibility of using an approximate computational model in the analysis of the magnetic field around a current lines enclosed in a thin conductive shield. The model uses the boundary element method (BEM), but the field in the shield is expressed with an approximate expression due to small thickness of the shield. This reduces the computational effort and avoids evaluating the nearly-singular integrals. (Przybliżona analiza harmonicznego pola magnetycznego przewodów z prądem w cienkościennej osłonie za pomocą MEB).
PL
Rozpatruje się możliwość zastosowania przybliżonego modelu obliczeniowego do analizy pola magnetycznego przewodów z prądem umieszczonych wewnątrz cienkościennej przewodzącej osłony. W tym celu wykorzystuje się metodę elementów brzegowych (MEB), lecz ze względu na założenie o małej grubości osłony pole wewnątrz niej wyraża się teoretyczną zależnością przybliżoną. Pozwala to zmniejszyć nakład obliczeń, a także uniknąć ewaluacji całek prawie osobliwych.
12
Content available remote Local dynamic buckling of C-shape profile subjected to bending
Urbaniak M., Kubiak T.
Mechanics and Mechanical Engineering
|
2011
|
Vol. 15, nr 2
133-148
EN
This paper deals with local dynamic buckling of thin-walled girder segments (short beam-columns) subjected to bending. Various shapes of pulse loading (triangle, trapezoid and rectangle) with a duration corresponding to the fundamental period of vibration were taken into account. Assumed boundary conditions correspond to a simple support, this agrees with conditions that exist in the place of the diaphragm in a long spar. The problem was solved by finite element method. In order to determine the critical load pulse amplitudes Volmir, Budiansky-Hutchinson, Ari-Gur and Simonetta criteria were employed.
13
Content available remote Membrane-flexural coupling effect in dynamic buckling of laminated columns
Mania R. J.
Mechanics and Mechanical Engineering
|
2010
|
Vol. 14, nr 1
137-150
EN
The purpose of this paper is the analysis of dynamic stability of thin-walled laminated columns of closed rectangular cross-section, subjected to in-plane pulse loading of finite duration. In the analysis with the FE Method the Lagrange strain tensor is assumed and various material characteristics are applied. In the solution the shear influence is considered according to the First Shear Deformation Theory displacement field. In the performed analysis the influence of walls initial imperfections, pulse shape and pulse duration on the dynamic buckling load are examined as well as the stacking sequence of laminated walls, the orientation of principal directions of separate layers and orthotropy ratio. The applications of some dynamic criteria are compared as well.
14
Content available remote Critical and postcritical behavior of thin-walled multicell column of open profile
Królak M., Mania R. J.
Mechanics and Mechanical Engineering
|
2010
|
Vol. 14, nr 2
281-290
EN
In the paper thin-walled isotropic and orthotropic multicell columns with open cross-section are considered. The local buckling and load carrying capacity analysis of these type columns under uniform compression was performed. Columns built of square shape cells with equal thickness of all walls and constant cross-section area were analyzed. The width of walls depends on the number of cells present in a column. The obtained results - it is the cell number and cross-section shape influence on the buckling load and load carrying capacity, are presented in the form of graphs and tables. The relatively high increase of local buckling stress value is demonstrated as well as the decrease of relationship between the load carrying capacity and buckling load - both events connected with increase of cell number.
15
Content available remote Application of different dynamic stability criteria in case of columns with intermediate stiffeners
Teter A.
Mechanics and Mechanical Engineering
|
2010
|
Vol. 14, nr 2
339-349
EN
In this paper, the dynamic responses of the open cross section columns with intermediate stiffeners subjected to in-plane pulse loading of a rectangular shape were concerned. Columns made of isotropic material were assumed to be simply supported at both loaded ends. The problem of the interactive buckling was solved by finite element method (FEM) - ANSYS 9. The critical dynamite load factors DLF has been determined using the most popular Budiansky-Hutchinson's criterion and they have been verified with author's versions of the phase portraits criterion.
16
Content available remote The use of thin-walled sections for energy absorbing components: a review
Bartczak B., Gierczycka-Zbrożek D., Gronostajski Z., Polak S., Tobota A.
Archives of Civil and Mechanical Engineering
|
2010
|
Vol. 10, no 4
5-19
EN
This paper presents the key aspects of the use of thin-walled sections for collision energy absorbing components. The process of deformation of thin-walled structures and the parameters expressing their energy absorption are described in detail. The research on improving the energy absorption of thin-walled sections, through the use of, e.g., tailored blanks, polyurethane foams and mechanical joining methods, conducted for many years in the Institute of Production Engineering and Automation at Wrocław University of Technology is reported.
PL
Przedstawiono najważniejsze aspekty związane z zastosowaniem struktur cienkościennych w elementach pochłaniających energię zderzenia. Szczegółowo omówiono proces deformacji struktur cienkościennych oraz parametry opisujące ich energochłonność. Opisano także metody poprawy energochłonności struktur cienkościennych łączonych techniką tailored blanks, poprzez przetłaczanie mechaniczne oraz wypełnianych pianką poliuretanową, testowane w Instytucie Technologii Maszyn i Automatyzacji Politechniki Wrocławskiej.
17
Content available Interactive buckling in thin-walled beam-columns with widthwise varying orthotropy
Kubiak T.
Journal of Theoretical and Applied Mechanics
|
2006
|
Vol. 44 nr 1
75-90
EN
An analysis of local buckling of thin-walled beam-columns, taking account global precritical bending within the first order approximation, is presented in the paper. The problem of interactive buckling of the structure is solved by means of Byskov and Hutchinson's (1977) or Koiter's (1976) approximation theory. Beam-columns made from orthotropic plates with the main directions of orthotropy parallel to the wall edges characterised by a widthwise varying orthotropy coefficient ni=Eyi/Exi are investigated. Beam-columns with open sections (i.e. channel sections), simply supported on the loaded edges, are analysed. The girders are subjected to loads which cause a uniform or linearly variable shortening of the edges.
PL
W pracy analizowano wyboczenie lokalne cienkościennych belek-słupów z uwzględnieniem globalnego dokrytycznego zginania w ramach przybliżenia pierwszego rzędu. Wyboczenie interakcyjne konstrukcji rozwiązano stosując aproksymacyjną teorię Byskova i Hutchinsona (1977) lub Koitera (1976). Badano belki-słupy zbudowane z płyt ortotropowych o głównych kierunkach ortotropii równoległych do krawędzi ścian charakteryzujących się zmiennym wzdłuż szerokości współczynniku ortotropii ni = Eyi / Exi. Analizowano belki-słupy oprzekro jach otwartych (ceowym i ceowym ze wzmocnieniem), przegubowo podparte na obciążonych brzegach. Dźwigary poddano obciążeniom ppowodującym równomierne i liniowo zmienne zbliżenie brzegów.
18
Content available remote Dynamic stability of an axially moving sandwich composite web
Marynowski K., Kołakowski Z.
Mechanics and Mechanical Engineering
|
2004
|
Vol. 7, nr 1
53-67
EN
Dynamic stability of an axially moving corrugated board web has been investigated. The board web is modeled as an thin-walled composite plate structure. Mathematical model of the moving web system has been derived using the classical laminated panel theory. In the solution of the problem the Koiter's asymptotic expansion and the numerical transition matrix method have been employed: The results of numerical investigations show the solutions to the linearized problem. The effects of the transport velocity and axial load of the web on its dynamic stability are presented.
19
Content available remote Buckling and initial post-buckling behaviour of thin-walled elliptic shells under bending
Królak M., Kołakowski Z.
Mechanics and Mechanical Engineering
|
2004
|
Vol. 7, nr 1
97-105
EN
The problem of the buckling and the initial post-buckling equilibrium paths of thin-walled cylindrical and elliptic shells subjected to bending has been carried out. Shell elements can be made of multi-layer orthotropic materials. The problem has been solved within the first order approximation of Koiter's asymptotic- theory, using the transition matrix method.
20
Content available remote An experimental investigation of critical states of thin-walled structures with stiffeners subjected to constrained torsion
Kopecki T.
Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika
|
2002
|
z. 58 [193]
163-168
EN
The results of experimental investigation of critical states of thin-walled open structures with different stiffeners, subjected to constrained torsion are presented in the paper. The tests were executed on the special steel models which complied with assumptions relative to stiffeners and boundary conditions. The purpose of the investigation was in order to obtain an information about buckling form of the structure and influence of kind of stringers (stiffeners) on the level of critical loads. Received results constituted the base to formulate very interesting conclusions, important from practical point of view.
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