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1
Content available remote A studyon liquefaction susceptibility of some soils from the coast of Marmara sea
100%
Sawicki A. , Świdziński W.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2006
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tom Vol. 54, nr 4
405-418
EN
The paper presents an estimation of liquefaction susceptibility of some soils from the coast of the Marmara Sea, which was heavily striken by the Kocaeli earthquake in 1999. Firstly, the results of field investigations are summarized. Then, the results of laboratory investigations of physical and mechanical properties of the soils collated from the sites investigated are presented. The mechanical properties relate to the compaction/liquefaction model of saturated soils. This model is briefly outlined, then respective experimental procedures dealing with its calibration described, and values of material parameters listed. Liquefaction potential of investigated soils is analysed using standard procedures, based on the grain size distribution curves and SPTs. Finally, the simulation of pore-pressure generation and onset of liquefaction of Turkish soils is carried out, using the compaction/liquefaction model. Discussion of some standard empirical procedures of estimation of liquefaction potential of saturated soils, conducted from the analytical point of view, is also presented.
2
Content available Analytical modelling cargoes displacement in wagon and tension in fastening
100%
Turanov K. , Timukhina E.
Transport Problems
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2008
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tom T. 3, z. 3
69-76
EN
The article deals with the conclusions of analytical modeling cargoes displacement relative wagon and tension in fastening on exposure to spatial system of forces.
3
Content available On the approach to the analysis of the growth of epitaxial layers by pulsed laser deposition
100%
Pankratov E. L.
Computer Methods in Materials Science
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2021
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tom Vol. 21, No. 4
203--208
EN
This paper considers an analytical approach for the prognosis of mass and heat transport during the growth of epitaxial layers by means of pulsed laser deposition. The approach provides the opportunity to make a prognosis which takes into account the spatial and temporal variations of their parameters and, at the same time, the nonlinearity of these processes. Based on this approach, the influence of the variation of several parameters on the growth process is investigated.
4
Content available Effective shaping of a stepped sandwich beam with clamped ends
100%
Magnucki K. , Kustosz J. , Goliwąs D.
Acta Mechanica et Automatica
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2023
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tom 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.
5
Content available On the method of changing the temperature of liquids and gases in a transportation system by local heating or cooling
100%
Pankratov E. L.
Computer Methods in Materials Science
|
2020
|
tom Vol. 20, No. 3
107--112
EN
In this paper we consider an approach of changing the temperature of liquids and gases in a pipeline by local heating and cooling. The approach based on changing of temperature of series sections of the pipeline due to external modification of temper-ature of these sections. This situation could be used for heat sink or increasing of temperature. A model of heat transfer based on transfer of heat in a pipeline with account convection due to liquid/gas transport has been introduced. We also introduce an ana-lytical approach for analysis of liquid/gas transport with account transport of heat due to convection. The approach gives a possi-bility to take into account spatial and temporal variation of parameters of transport and at the same time to take into account non-linearity of considered processes.
6
Content available Analytical model of a composite girder with flexible adhesive bondline
88%
Szeptynski P.
Archives of Mechanics
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2024
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tom Vol. 76, nr 1-2
155--189
EN
The paper presents a linear elastic one-dimensional Discrete Layer–Wise (DLW) analytical model of a composite girder consisting of two beams bonded together with a layer of a flexible adhesive. The model takes into account both longitudinal and transverse deformation of component beams, the First Order Shear Deformation Theory (FSDT) for these adherends as well as extensibility of the adhesive layer. A system of governing equations is derived and a general solution is found with the use of the method of generalized eigenvectors. Two examples are analyzed both with the use of the considered 1D analytical model and a 3D Finite Element Analysis (FEA) in order to validate predictions of the introduced theory. Satisfactory agreement is found between theoretical and numerical results.
7
Content available remote Designing a monolithic tip-tilt-piston flexure manipulator
75%
Hao G. , He X.
Archives of Civil and Mechanical Engineering
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2017
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tom Vol. 17, no. 4
871--879
EN
This paper deals with the design of a monolithic tip-tilt-piston flexure manipulator for high-precision applications. The manipulator is first proposed with consideration of actuation isolation, which is a symmetrical and compact design and can be monolithically fabricated without using additive manufacturing. Kinematic and kinetostatic models are then analytically derived for quick parameter assessments. A case study is discussed finally, where a monolithic prototype has been made using CNC milling machining, comparisons among analytical, FEA and testing results are also undertaken.
8
Content available Free flexural vibrations of an expanded-tapered sandwich beam
75%
Magnucki K. , Kustosz J. , Goliwąs D.
Vibrations in Physical Systems
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2023
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tom Vol. 34, nr 1
art. no. 2023114
EN
The paper is devoted to the analytical modelling of a simply supported expanded-tapered sandwich beam. The simplified analytical model of this beam with omitting the shear effect is elaborated. Based on Hamilton’s principle, the differential equation of motion of this beam is obtained. This equation is analytically solved with consideration of the deflection line of this beam subjected to its own weight. The fundamental natural frequencies for exemplary beams are derived. Moreover, the FEM model of the beam in the ABAQUS is developed. The calculation results of the fundamental natural frequency of exemplary beams of these two methods are presented in tables and figures.
9
Content available remote Stress intensity factor against fracture toughness in functionally graded geopolymers
63%
Nazari A. , Sanjayan J. G.
Archives of Civil and Mechanical Engineering
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2015
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tom Vol. 15, no. 4
1007--1016
EN
The benefits of producing functionally graded geopolymer in terms of their modified stress intensity factor and fracture toughness are discussed in the present paper. Pre-notched functionally graded geopolymer beams were fabricated by two different fly ash-based geopolymer mixtures. The load was applied parallel to the functionally graded region; two different structures were evaluated by changing the position of the notch. The obtained results indicated that the crack nucleation and growth depend on the interaction between stress intensity factor and fracture toughness. According to the notch position, a crack experience upward or downward variations of properties. When the crack is located in the mixture with the lowest toughness, the variation of properties is called upward and vice versa. A crack facing an upward fracture toughness region is arrested, when the applied stress is equal to the weakest strength of the constituent materials. On the other hand, the fracture toughness of a crack facing a downward fracture toughness gradient is more than that facing an upward one, without any subsequent arresting. It was shown that the position of the notch, and experiencing of downward or upward gradient in mechanical properties mainly determine the final flexural strength of the specimens.
10
Content available remote Modelling of linear elasticity and viscoelasticity of thermosets and unidirectional glass fibre-reinforced thermoset-matrix composites. Part 1, Theory of modelling
63%
Klasztorny M. , Nycz D. B.
Composites Theory and Practice
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2022
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tom R. 22, nr 1
3--15
EN
The paper presents advanced analytical modelling of the linear elasticity and viscoelasticity of thermosets and unidirectional long glass fibre-reinforced thermoset-matrix (UFRT) composites. New non-aging materials fully relaxed after the curing and post-curing processes are considered. Quasi-static long-term isothermal reversible viscoelastic processes under normal conditions are modelled. The thermosets are isotropic materials with viscoelastic shear strains and elastic bulk strains, and the fibres are isotropic and elastic. New rheological models for thermosets and UFRT composites, described by the smallest possible number of material constants, are developed. The viscoelastic generic function for shear/quasi-shear stresses is assumed as the Mittag-Leffler fractional exponential function in an integral form. The thermoset is described by two elastic and three viscoelastic parameters. The homogenized UFRT composite is described by five elastic and five viscoelastic parameters. Conjugated/unconjugated standard/inverse constitutive equations of the linear elasticity/elasticity-viscoelasticity governing thermosets and UFRT composites are formulated. The equations are mutually analytically transformable.
11
Content available remote Analysis of effects of magnetic slot wedges on characteristics of large induction motor
63%
Dems M. , Komęza K. , Sykulski J. K.
Przegląd Elektrotechniczny
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2012
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tom R. 88, nr 7b
73-77
EN
Magnetic slot wedges are often used to improve starting performance of large induction motors. In this paper we have investigated – through simulation – the effects of the wedges on the performance characteristics of the motor and core losses under no load condition. Both analytical and hybrid two-dimensional field-circuit models have been used. In order to reliably establish the parameters of the end connections of the rotor cage, whose values significantly influence the results of simulation, a three-dimensional model was developed, also useful for verification purposes at standstill. The simulation has demonstrated the effects of the wedges on the starting performance but revealed little influence on the core losses.
PL
W artykule przedstawiono wpływ zastosowania klinów magnetycznych na charakterystyki eksploatacyjne i straty w rdzeniu silników indukcyjnych dużej mocy w warunkach obciążenia. Obliczenia zostały wykonane z wykorzystaniem hybrydowego modelu obwodowo-polowego 2D oraz metodami analitycznymi. Wyniki obliczeń porównano z wynikami pomiarów.
12
Content available A study on liquefaction susceptibility of some soils from the coast of Marmara sea
63%
Sawicki A. , Świdziński W.
|
13
Content available Material model and revealing the truth
51%
Czarnecki L. , Sokołowska J. J.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2015
|
tom Vol. 63, nr 1
7--14
EN
The paper refers to the approach used in science, specifically in building materials engineering, assuming the possibility of material modeling, including modeling of the technical characteristics of building materials of various compositions as well as modeling phenomena/processes that occur during the use of materials and structures made from them. The authors analyze the merits of the approach of modeling in the context of compliance computational models to reality, consider the significance of the selection of the proper model (type of mathematical function, number of input data) which should be based on the knowledge of modeled material or phenomenon and later adequate verification of the model. The authors also underline importance of proper interpretation of results obtained by calculation. Misrepresentation may result in a misstated model of the studied phenomenon and lead to incorrect conclusions, which puts the researcher far from the truth, that he or she should always seek for.
14
Content available remote Analytical model end plate bolted joint under bending moment and axial force load
51%
Pisarek Z.
Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture
|
2015
|
tom z. 62, nr 3/II
325--336
EN
In typical buildings with steel-concrete composite floors, joints are designed to transmit only hogging bending moment. In case of the large horizontal loads due to wind, earthquake or accidental events, sagging bending moments in the joint and not to neglect axial force can also occur. Additionally, large deformations of the structure cause tying and prying effects. The joints loaded in this way are changing their characteristics, and their strength for the bending moment is decreased. In global analysis of the structures, the accurate knowledge of the characteristics of the joints allows for determine accurate internal forces in the structural elements. Procedures presented in literature and standards [1] allow for appointing of characteristics of the joint only for bending moment without taking into account axial loads. In the paper, a mechanical model based on “component method” for evaluation of characteristics of the composite joint under bending and axial loads is presented. The influence of tying and prying actions on distribution of the internal forces in a joint is also analyzed. The procedure for calculation of the characteristics of the composite joint with bolted end-plate connection is elaborated too.
PL
W typowych budynkach ze stropami zespolonymi stalowy-betonowy, węzły są projektowane głownie do przenoszenia momentów zginających. W przypadku dużych obciążeń poziomych powstałych w wyniku oddziaływań wiatru, trzęsień ziemi lub zdarzeń wyjątkowych, w węzłach pojawia się moment dodatni i siła osiowa o niezaniedbywalnej wartości. Dodatkowo, duże odkształcenia konstrukcji mogą wywoływać siłę skleszczenia efekt cięgnowy w ryglach ramy. Obciążone w taki sposób węzły zmieniają swoją charakterystykę, a ich nośność na zginanie maleje. W analizie globalnej konstrukcji, znajomość rzeczywistych charakterystyk węzłów pozwala na określenie dokładnego rozkładu sił wewnętrznych w elementach konstrukcji. Procedury przedstawione w literaturze i normie [1] pozwalają na wyznaczanie charakterystyki węzłów jedynie obciążonych momentem zginającym bez uwzględnienia siły osiowej. W artykule przedstawiono, oparty na metoda składnikowej, model mechaniczny, przydatny do określenia charakterystyki węzła zespolonego poddanego obciążeniu momentem zginającym i siłą osiową. Przeanalizowano również wpływ efektu kleszczenia i efektu cięgnowego na rozkład i wartość sił wewnętrznych w połączeniu. Opracowano procedury do obliczania takich połączeń i na przykładzie wykonano porównanie otrzymanej z modelu charakterystyki węzła z wynikami badań doświadczalnych.
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