BazTech - Yadda

1

A study of factors affecting wear and destruction of teeth in gear mechanisms

Mustafayev Amir G., Nasirov Chingiz R

Nafta-Gaz

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2023

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R. 79, nr 9

604--610

EN

Transmission gears are very widely used in the modern construction of the machine. Even though electrical transmissions are used, mainly mechanical transmissions are widely used in the machine building industry as they are independent and better than other transmissions. Distributing power between the transmission mechanisms and working units of various machines, by changing the angle of momentum by adjusting the speed of the parts, it is possible to change the type of movement, turn the mechanism on and off, and change the direction of the transmission mechanisms. One of the most widespread types of transmission technology is gear transmission. Tens of thousands of kilowatt-hours of gears can be transmitted. The advantages of gear transmission in comparison with others are their ability to maintain their reliability and long-term functioning of the teeth, high value of the working coefficient (0.90–0.99), simple construction, lack of special service, simplicity of the transmission number and compactness of dimensions. The missing aspects of these transmissions are high precision in their preparation and installation, and low noise level. The main criterion for the working ability of the closed gear transmissions is the contact endurance of the active surface of the tooth. For this reason, the main dimensions of the transmission are determined by the contact tension and by teeth bending.

PL

Przekładnie zębate znajdują szerokie zastosowanie w nowoczesnych maszynach. Chociaż stosuje się także przekładnie elektryczne, to w przemyśle maszynowym stosowane są głównie przekładnie mechaniczne, ponieważ są one niezależne i lepsze od innych rodzajów przekładni. Przekładnie zębate umożliwiają rozprowadzenie mocy między mechanizmami przekładni a różnymi jednostkami roboczymi poszczególnych maszyn, poprzez zmianę kąta pędu i regulację prędkości części. Dzięki temu można zmieniać rodzaj ruchu, włączać i wyłączać mechanizmy oraz zmieniać kierunek mechanizmów przekładni. Jednym z najbardziej powszechnych rodzajów przekładni są przekładnie zębate. Mogą one przenosić dziesiątki tysięcy kilowatogodzin mocy. Przewaga przekładni zębatych nad innymi mechanizmami tego typu tkwi w ich niezawodności, trwałości zębów, wysokiej wartości współczynnika pracy (0,90–0,99), prostej konstrukcji, braku wymogu specjalnego serwisowania, prostocie liczby przełożeń i niewielkich wymiarach. To, czego im brakuje, to zachowanie wysokiej precyzji wykonania i montażu oraz niski poziom hałasu. Głównym kryterium decydującym o sprawności zamkniętych przekładni zębatych jest wytrzymałość styku aktywnej powierzchni zęba. Z tego powodu główne wymiary przekładni zależą od naprężenia stykowego i zginania zębów.

2

Wykorzystanie zdolności pochłaniania energii do wyznaczania wytrzymałości resztkowych fibrokompozytów

Głodkowska Wiesława, Laskowska-Bury Joanna, Lehmann Marek

Materiały Budowlane

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2023

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nr 3

1--4

PL

W artykule omówiono sposób wyznaczania wytrzymałości resztkowych z wykorzystaniem zdolności pochłaniania energii przez fibrokompozyt. Badania przeprowadzono przez zginanie płyt o przekroju kwadratowym podpartych przegubowo na obwodzie. Określone w ten sposób wytrzymałości resztkowe cechują się znacznie mniejszym współczynnikiem zmienności niż wyznaczone wg PN-EN 14651:2007. Opisane badanie jest alternatywą dla 3-punktowego zginania belek i pozwala na wyznaczenie tej cechy z większą wiarygodnością.

EN

The article discusses the method of determining residual strength using the energy absorption capacity of fibrecomposite. The research was carried out by bending square cross-section plates simply supported at the perimeter. The residual strengths determined in this way are characterized by a much lower coefficient of variation than those determined using the normative method according to PN-EN 14651:2007. The described test is an alternative to 3-point bending of beams and allows to determine this feature with greater reliability.

3

Wykorzystanie technologii druku 3D do wzmocnienia zginanych zimnogiętych profili typu C

Major Maciej, Kalinowski Jarosław, Kosiń Mariusz

Materiały Budowlane

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2023

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nr 10

21--25

PL

Artykuł przedstawia wykorzystanie technologii druku 3D do wzmocnienia stalowych profili zimnogiętych typu C. Przedmiotem analizy były zimnogięte belki stalowe usztywnione w połowie rozpiętości elementami wykonanymi w technologii druku 3D. Zaprezentowano wyniki doświadczalno-numeryczne trójpunktowego zginania. Obliczenia numeryczne przeprowadzono, uwzględniając nieliniowość materiału z uwzględnieniem dużych przemieszczeń. Analiza potwierdziła zwiększenie sztywności modeli poddanych trójpunktowemu zginaniu z wykorzystaniem usztywnienia wykonanego w technologii druku 3D z użyciem filamentu ABS.

EN

The article presents the use of 3D printing technology to strengthen cold-formed C-type steel profiles. The subject of the analysis were cold-formed steel beams stiffened in the middle of the span with elements made in 3D printing technology. The paper presents experimental and numerical results of three-point bending. Numerical calculations were carried out in the nonlinear range of the material and taking into account large displacements. The analysis confirmed the increase in stiffness of the models subjected to three-point bending with the use of a stiffener made in the incremental printing technology with the use of ABS filament.

4

Badania doświadczalne zginanych kształtowników giętych na zimno

Górski Marcin, Budziński Rafał, Sieńkowska-Szpetnar Katarzyna

Inżynieria i Budownictwo

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2023

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R. 79, nr 1-2

30--34

PL

W artykule przedstawiono zakres oraz wyniki badań doświadczalnych elementów dwugałęziowych z ceowych lub zetowych kształtowników giętych na zimno o rozpiętości 3 m w schemacie czteropunktowego zginania. Porównano nośności otrzymane z badań doświadczalnych dla przekrojów bazowych i przekrojów z dodatkowymi usztywnieniami na środniku oraz opisano uzyskane formy zniszczenia.

EN

The article presents the course and results of experimental tests conducted on built-up members consisting of two cold-formed channel or zeta sections with a span of 3m in four point bending scheme. The bending resistance obtained from experimental tests for basic sections and sections with additional stiffeners on the web are compared and the observed forms of failure are described.

5

Theoretical probabilistic nonlinear analysis of post-tensioned bridge cross-sections with the application of random fields

Owerko Piotr

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 2

127--136

EN

The paper presents a proprietary procedure for the analysis of normal stress distributions in post-tensioned cross-sections. It has a significant advantage over conventional commonly used approaches based solely on the envelope analysis as it provides stress levels in all components of the cross-section. The procedure was used in a series of probabilistic analyses with the adoption of random fields. These fields represented uncertainties in strain-stress relationship in concrete. The analysis covered several types of cross-sections and several types of random fields. Key observations from the conducted simulations are as follows: (I) the widest ranges of the probable maximum stresses (i.e. the lowest indexes of reliability) were obtained for sections with relatively low heights of the compressive zone. (II) The highest probabilistic sensitivity to the type of random field used was found in tall sections with a relatively large compressive zone. (III) The greatest sensitivity to batch uncertainties was evident in all cross-sections when using squared exponential random fields. (IV) The greatest relative sensitivity to the batch uncertainties in the form of the random field compliant with the guidelines of the Joint Comity of Structural Safety (JCSS) was evident in the analyses of the tallest cross-section corresponding to the incrementally launched bridges.

6

Numerical failure analysis of laminated beams using a refined finite element model

Layachi Maroua, Khechai Abdelhak, Ghrieb Abderrahmane, Layachi Safa

Advances in Materials Science

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2023

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Vol. 23, nr 1(75)

32--57

EN

In the present investigation, laminated composite beams subjected to a bending static loading are studied in order to determine their failure mechanisms and the first ply failure (FPF) load. The FPF analysis is performed using a refined rectangular plate element. The present element is formulated based on the classical lamination theory (CLT) to calculate the in-plane stresses. To achieve this goal, several failure criterions, including Tsai-Wu, Tsai-Hill, Hashin, and Maximum Stress criteria, are used to predict failure mechanisms. These criterions are implemented within the finite element code to predict the different failure damages and responses of laminated beams from the initial loading to the final failure. The numerical results obtained using the present element compare favorably with those given by the analytic approaches. It is observed that the numerical results are very close to the analytical results, which demonstrates the accuracy of the present element. Finally, several parameters, such as fiber orientations, stacking sequences, and boundary conditions, are considered to determine and understand their effects on the strength of these laminated beams.

7

Effective shaping of a stepped sandwich beam with clamped ends

Magnucki Krzysztof, Kustosz Joanna, Goliwąs Damian

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 2

200--204

EN

The aim of this work is to propose a sandwich beam with stepped layer thickness in three parts along its length. The total depth, width of the cross-section and its mass are constant. The beam is under a uniformly distributed load. The system of two equilibrium equa-tions was formulated for each part based on the literature. This system was analytically solved for the successive parts of the beam and the functions of the shear effect and deflection were determined in them. The effective stepped layer thicknesses was determined on the basis of the adopted criterion for minimizing the maximum deflection of the beam. The example calculations were made for two elected beams. The effective shapes of these beams are shown in the figures. Moreover, FEM numerical calculations of the deflections of these beams are performed.

8

An innovative approach to fabrication with photo-cured resins by shell-printed-core-casting

Szymczyk Emil, Rećko Maciej, Dzierżek Kazimierz, Sapiołko Karol

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 4

485--489

EN

Modified LCD-based method was used to print three-dimensional (3D) elements. This innovative method combines printing the external shell and filling, thus obtaining mould by casting resin. In order to compare the properties of prints obtained with this method with the ones fabricated in a standard procedure, we conducted bending tests of vertically/horizontally printed and shell-printed cast specimens. The shell-cast samples showed higher flexural strength and larger values of apparent Young’s modulus. The presented results also concern the kinetics of curing samples obtained with different fabrication routes.

9

Wybrane problemy zginania żelbetowych stropów gęstożebrowych wg PN-EN 15037

Musiał Michał, Grzymski Filip, Pazdan Maciej, Trapko Tomasz

Materiały Budowlane

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2022

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nr 11

116--118

PL

Wprowadzenie PN-EN 15037 wymusiło m.in.: konieczność dostosowania dokumentacji technicznej, a także wprowadzenie zmian w geometrii i zbrojeniu oferowanych prefabrykatów. W artykule opisano problemy związane z dostosowaniem stropów Teriva do wymagań PN-EN 15037. Skoncentrowano się na nośności zgięciowej tych stropów. Zaproponowano sposób jej obliczania, który prowadzi do pewnych oszczędności w zbrojeniu (w stosunku do dotychczas stosowanego typoszeregu belek), pomimo zwiększenia obciążeń.

EN

The implementation of PN-EN 15037 exacted i.a.: the necessity of the technical documentation updating, the introducing of geometry and reinforcement changes of offered prefabs. In the paper the problems concerning the adaptation of Teriva floors to the PN-EN 15037 requirements were described. The paper focused on bending load capacity of these floors. The method of the load capacity calculation was proposed. It leads to certain reduction of reinforcement (in relation to beams applying so far) despite loads increase.

10

Pręty kompozytowe BFRP jako zbrojenie w prefabrykowanych belkach betonowych

Krassowska Julita, Kosior-Kazberuk Marta

Materiały Budowlane

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2022

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nr 4

30--32

PL

Do głównych zalet prętów kompozytowych BFRP (basalt fibre reinforced polymers) należy zaliczyć odporność na korozję oraz małą masę. Ich wykorzystanie w budownictwie jest jednak ograniczone ze względu na wysoki koszt początkowy oraz zbyt małą sztywność elementów konstrukcyjnych. Rozwiązaniem może okazać się pełna prefabrykacja takich elementów. W artykule zaprezentowano wyniki badań porównawczych prefabrykowanych elementów belkowych o długości 4500 mm ze zbrojeniem podłużnym oraz poprzecznym w postaci prętów stalowych i prętów kompozytowych BFRP. Określono nośność na zginanie oraz ścinanie, a także ugięcie i charakter zniszczenia badanych elementów.

EN

Composite bars BFRP (basalt fiber reinforced polymers) are increasingly used in construction. Their main advantages are corrosion resistance and the lightweight of the bars. However, despite the advantages over steel bars, the development of structures using non-metallic composite bars is limited due to the high initial cost and insufficient stiffness of the structural elements. The solution may be the full prefabrication of such elements. The article presents the results of a comparative study of 4500 mm long prefabricated beam elements with longitudinal and transverse reinforcement in the form of steel bars and BFRP composite bars. The resistance to bending and shear was determined, as well as the deflection and the nature of the failure of the tested elements.

11

Strength analysis of sandwich beams with linear elastic inner layer

Kimura Koichi

Journal of Applied Mathematics and Computational Mechanics

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2022

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Vol. 21, nr 3

31--44

EN

A waterproof or water-resistant sandwich structure which consists of housing chassis and a gasket requires that gasket contact pressure, which depends on bolt axial force, is greater than the design minimum pressure on the entire circumference. However, it is also necessary that gasket contact pressure is smaller than the maximum permissible gasket pressure. If the maximum stress in chassis can be calculated from bolt axial force, gasket specifications and chassis stiffness, it is helpful for a design of such waterproof structures. In this study, chassis have been regarded as Bernoulli-Euler beams, and two simple numerical methods have thus been derived. Numerical results using the proposed method are sufficiently converged even in case that the number of partitions is about 10.

12

Zbrojenie kompozytowe z włókien szklanych - potencjalne źródło problemów inżynierskich

Błyszko Jarosław

Inżynieria i Budownictwo

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2022

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R. 78, nr 3-4

128--131

PL

W artykule omówiono zastosowanie prętów kompozytowych z włókna szklanego jako alternatywnego sposobu zbrojenia elementów zginanych. Przedstawiono koncepcję zbrojenia minimalnego wyliczanego na podstawie układu sił w przekroju zginanym, a następnie porównano z wynikami badań. Wykazano, że w przypadku zbrojenia GFRP opieranie się jedynie na zależnościach statycznych może prowadzić do zaniżenia nośności.

EN

This paper presents the use of fiberglass composite bars as an alternative reinforcement method for flexural elements. The concept of the minimal reinforcement calculated from the balance of forces in the element is presented and then compared with test results. It is shown that when calculating the minimum degree of GFRP reinforcement, basing only on static relationships can result in too low a load capacity.

13

Bending of a stepped sandwich beam: the shear effect

Kustosz Joanna, Magnucki Krzysztof, Goliwąs Damian

Engineering Transactions

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2022

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Vol. 70, iss. 4

373--390

EN

This paper is devoted to the stepped sandwich beam with clamped ends subjected to a uniformly distributed load. The bending problem of the beam is formulated and solved with consideration of the classical sandwich beam of constant face thickness. Two differential equations of equilibrium based on the principle of the stationary potential energy of the classical beam are obtained and analytically solved. Moreover, numerical-FEM models of the beams are developed. Deflections for an exemplary beam family with the use of two methods are calculated. The results of the study are presented in figures and tables.

14

Designing a Three-Dimensional Woven Fabric Structure as an Element of a Baby Stroller

Bethalihem Samuel T., Barburski Marcin, Lemmi Tsegaye Sh.

Autex Research Journal

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2022

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Vol. 22, no. 2

148--154

EN

A baby stroller allows the transportation of a child over long or short distances. The materials used to produce the stroller make it heavy for users, which creates difficulties when lifting the stroller. The goal of this project was to design and fabricate a three-dimensional (3D) fabric structure that can be used as part of a stroller seat to improve its mechanical and physical properties. The idea of implementing a woven 3D system allows the development of an egg-shaped or shell-like structure as part of a stroller seat. The combination of double-woven material and honeycomb polypropylene (as the reinforcing material) was used to create a 3D composite structure. Single and double layers of polypropylene honeycomb sandwiched within layers of linen flax fabric were used to prepare the composite samples. Subsequently, tests on mechanical and physical properties, such as density, flexural strength, and tensile strength, were carried out. Analysis of the results showed that the composite with one layer of honeycomb has half the density of polyvinyl chloride.

15

Investigation of Thermal and Mechanical Properties of Three-Dimensional Braided Composite Materials

Arbaoui Jamal, Aucher Jérémie, Gomina Moussa, Breard Joel

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1325--1332

EN

This paper investigates the thermal and mechanical properties of a composite made from a combination of 2063-epoxy resin and three different braided carbon-fiber fabric reinforcements. These fibres consist of HTS carbon, HTS carbon braided with nickel coated carbon and HTS carbon braided with nickel coated copper, respectively. The composites were manufactured through resin transfer molding (RTM) route. The thermal diffusivity of carbon fibers composites was measured at different temperature by using a flash method. The transverse and planar thermal conductivities were determined by measuring the specific heat, density and thermal diffusivities, respectively. The current research highlights the influence of adding nickel coated carbon and nickel-plated copper wires on the braided composites. The evaluation shows that the HTS carbon braided manufactured with nickel-plated copper wires presents higher in-plane thermal conductivity (in direction parallel of the fibres) when comparing to HTS carbon and HTS carbon braided manufactured with nickel coated carbon. The thermal conductivity benefits of those composite were achieved at the expenses of lower mechanical properties of braided composites investigated.

16

Natural filler based composite materials

Nayeeif A.A., Hamdan Z.K., Metteb Z.W., Abdulla F.A., Jebur N.A.

Archives of Materials Science and Engineering

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2022

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Vol. 116, nr 1

5--13

EN

Purpose: The first goal is to get rid of waste and reduce environmental pollution, and the other goal is to investigate the effect of these fibres on properties (resistance of composite materials for bending and tensile testing) of polyester and use them in applications. Also, The moisture environment effect on the properties of composite materials was studied. Design/methodology/approach: It uses natural fibres, which are considered waste, namely eggshell and sawdust with polyester. Several samples were prepared with different weight percentages (30% and 40%), and their mechanical properties were studied and immersed in water for 15 days. And studying the effect of water on these properties. It was found that it is possible to use these fibres (waste) with polyester and benefit from them. It was found that when adding fibres to polyester, the tensile strength decreases, but the bending increases the strength. Finally, it was found that when the samples are immersed in water, the material weakens, and its mechanical properties decrease. Findings: It can be noticed that adding natural fibres by 40% and 30% improved the mechanical properties of polyester in the bending test, where the bending test increased with increased volume fraction of fibre. It can be noticed that adding natural fibres by 40% and 30% decreased the mechanical properties (tensile strength) of polyester in a tensile test. When the natural composite materials were treated with water for 15 days, water decreased the mechanical properties in bending and tensile test. Research limitations/implications: One of the limitations of this research that was found through the work is that when increasing the weight ratios of the fibres added to polyester leads to the failure of polyester, so we recommend using lower weight ratios of fibre. Practical implications: One of the limitations of this research that was found through the work is that when increasing the weight ratios of the fibres added to polyester leads to the failure of polyester, so we recommend using lower weight ratios of fibre. Originality/value: The original value of this research is the use of fibres that are considered waste, their reuse, and utilization in some applications that do not require composite materials with high mechanical properties.

17

Study on mechanical properties of notched steel wire under tension and bending

Fei Hongyu, Sun Quansheng, Yang Jianxi

Archives of Civil Engineering

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2022

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Vol. 68, nr 4

467--480

EN

The fracture reason of steel wire cable is complex, and the corrosion and local bending effect of anchorage end of steel wire cable under tension are one of the main factors. Taking the steel wire of an arch bridge cable as the research object, the notch method was used to simulate the corrosion pits on the surface of the steel wire, and the tension and bending mechanical properties of the high strength notched steel wire were tested. The bending finite element model of the high strength steel wire was established by ANSYS WORKBENCH, and the tension and bending mechanical properties of the notched steel wire under different vertical loads and pretension were studied. The test and calculation results show that the test data are close to the finite element calculation results and the variation law is consistent. Under the same vertical load, the deformation of steel wire notch decreases with the increase of pretension; The stress at the bottom of the notch is the largest at 180° direction and the smallest at 90° direction of the vertical load. Under the same vertical load and pretension, the stress of spherical shape at the notch is the largest, followed by ellipsoid shape, and groove shape is the smallest, and there is a high stress zone at the edge of groove shape. When the pretension is applied, the initial stress increases with the increase of pretension, while the stress at the notch caused by bending decreases with the increase of pretension.

18

Overall buckling performance of high strength steel welded I-sections under combined axial compression and bending

Huang Bin, Zhang Wen-Fu

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

369--384

EN

This paper presents a numerical investigation into the high strength steel (HSS) welded I-section overall buckling performance with respect to the major axis under combined axial compression and bending. The validation of FE models compared with the existing test data to verify the appropriateness of the element division and boundary condition was firstly conducted. In line with the FE arrangement verified, separate 890 numerical models, covering a broader range of eight steel grades (460 MPa, 500 MPa, 550 MPa, 620 MPa, 690 MPa, 800 MPa, 890 MPa and 960 MPa), different overall slenderness and various eccentricities were designated. Subsequently, the comparison of the resistance prediction codified design rules in EN 1993-1-1, ANSI/AISC 360-10 and GB50017-2017 was preferentially operated, by the instrumentality of the normalized axial compression-bending moment curves. The results graphically revealed that, the provision given in ANSI/AISC 360-10 concerned in the present work was the most loose, whereas, the corresponding content set out in EN 1993-1-1 and GB50017-2017 was relatively on the safe side. Taking account of the FE results, the conservative shortcomings of the considered rules in EN 1993-1-1 and GB50017-2017 were further highlighted. Especially, the disparity of EN 1993-1-1 and numerical results was higher to 27%, from the perspective of a definition given in the present work. In contrast, the provision in ANSI/AISC 360-10 yielded a relatively accurate prediction, on average. Based on the numerical program, an alternative formula for the HSS welded I-section beam-columns with a general expression form was sought, which intimately reflected the effect of overall slenderness.

19

A parametric analysis of free vibration and bending behavior of sandwich beam containing an open-cell metal foam core

Garg A., Chalak H. D., Belarbi M. O., Zenkour A. M.

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e56, 2022

EN

Free vibration and bending behavior of sandwich beams containing open-cell metal foam core are studied in the present work using zigzag theory. Hamilton’s principle and the principle of minimum potential energy are applied for determining the governing equations for free vibration and bending behavior, respectively. Three types of distribution of pores are used during the present study. The influence of the distribution of pores, end condition, thickness of the core, foam coefficients on beam behavior is studied in detail. The face sheets are assumed to be made up of the same material like foam. It was noticed that the nature of the distribution of pores and the end conditions widely determine the behavior of the beam.

20

Zginanie muru w płaszczyźnie prostopadłej do powierzchni ściany – obciążenia i mechanizmy zniszczenia

Piekarczyk Adam

Materiały Budowlane

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2021

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nr 2

27--29

PL

Artykuł jest pierwszą częścią cyklu omawiającego przypadek ścian murowanych zginanych w płaszczyźnie prostopadłej do płaszczyzny muru. Opisano w nim obciążenia prostopadłe do powierzchni ścian, które wywołują omawiany przypadek pracy konstrukcji murowanej. Zaprezentowano mechanizmy zniszczenia muru w dwóch ortogonalnych płaszczyznach oraz ich warianty.

EN

The article is the first part of the cycle discussing the case of bending masonry walls in a plane perpendicular to the masonry plane. Loads and actions perpendicular to the wall surfaces, which cause the discussed case of masonry structure work, are described. The mechanisms of wall failure in two orthogonal planes and their variants were presented.