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Abstract

This paper presents an experimental analysis of flexural capacity and deformability of structural concrete slabs prepared as composite members consisting of two concrete layers made of reinforced ordinary concrete (N) and fiber reinforced concrete (SFRC). The reinforced concrete composite slabs used in the tests were prepared in the dimensions of 600 x 1200 x 80 mm. The basis was composed of two layers consisting of SFRC, one as the top layer, and one as ordinary concrete. The results of the analysis confirm a significant improvement of structural properties of the composite slab in comparison to the slabs prepared wholly of ordinary concrete.

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Authors and Affiliations

B. Sadowska-Buraczewska
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Abstract

Buckling and postbuckling response of thin-walled composite plates investigated experimentally and determinated analytically and numerically is compared. Real dimension specimens of composite plates weakened by cut-out subjected to uniform compression in laboratory buckling tests have been modelled in the finite element method and examined analytically based on P-w2 and P-w3 methods. All results were obtained during the experimental investigations and the numerical FEM analysis of a thin-walled composite plate made of a carbon-epoxy laminate with a symmetrical eight-layer arrangement of [90/-45/45/0]s. The instrument used for this purpose was a numerical ABAQUS® program.

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Authors and Affiliations

K. Falkowicz
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Abstract

This article provides an initial analysis, from a historical standpoint, of the problematic nature of conceptualizations of the notion of gene in molecular genetics. The starting point is an historical outline of the relation between classical genetics and molecular genetics; it is indicated how the conceptual baggage of classical genetics influenced the development of the concepts of gene used later in molecular biology. I also reveal two problems of genes in the philosophy of science, i.e., skepticism concerning genes and the concept of nominal gene. I conclude that concept of gene functioning within the framework of molecular genetics should be considered from the point of view of experimentalism and pragmatism. It seems that the concept of gene on the molecular level should be conceptualized—in order to remain functional—as broadly as possible and in relation to genetic material.

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Authors and Affiliations

Aleksander A. Ziemny
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Abstract

The residual stress analysis is discussed in the paper. However, the author has not intended to present, even partially, all aspects of this very broad problem. The aim of this work has been limited to a review of conternporarily used experimental, numerical and hybrid methods, and to outline the directions of possible developments.
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Authors and Affiliations

Marek Bijak-Żochowski
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Abstract

This work discusses the heat transfer aspects of the neonate’s brain cooling process carried out by the the device to treat hypoxic-ischemic encephalopathy. This kind of hypothermic therapy is undertaken in case of improper blood circulation during delivery which causes insufficient transport of oxygen to the brain and insufficient cooling of the brain by circulating blood. The experimental setup discussed in this manuscript consists of a special water flow meter and two temperature sensors allowing to measure inlet and outlet water temperatures. Collected results of the measurements allowed to determine time histories of the heat transfer rate transferred from brain to the cooling water for three patients. These results are then analysed and compared among themselves.

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Authors and Affiliations

Dominika Bandoła
Marek Rojczyk
Ziemowit Ostrowski
Joanna Łaszczyk
Wojciech Walas
Andrzej J. Nowak
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Abstract

This paper deals with the experimental validation of the suitability of the method for measuring radial variations of components on the process tool. The tests were conducted using a computerized PSA6, which was compared to a Talyrond 73. The results of measurement of roundness deviations as well as roundness profiles were analyzed for a sample of 70 shafts. The roundness deviations were assessed by determining the experimental errors, while the profiles obtained with the tested device were compared to those registered by the reference device using three correlation coefficients.

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Authors and Affiliations

Krzysztof Stępień
Włodzimierz Makieła
Stanisław Adamczak
Adam Janusiewicz
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Abstract

The paper presents the application of the newly developed method of the solution of nonlinear equations to the adaptive modelling and computer simulation. The approach is suitable when the system of equations can be arranged in such a way that it consists of a large number of linear equations and a smaller number of nonlinear equations. This situation occurs in the case of adaptive modelling of mechanical systems using finite elements or finite differences techniques. In this case the classical least square method becomes very effective. The paper presents several examples of the application of the method. A solution to the, so called, “black box” problem is also presented.

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Authors and Affiliations

S.A. Łukasiewicz
M.H. Hojjati
R. Qian
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Abstract

A simple resistance-based method was used to study the epoxy-carbon composite material. Measurement of changes of the resistance between contacts, located on the composite specimens, allows detecting the damage process in quasi-static and fatigue tests. The method can be useful to determine the margin of safety of composite elements.

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Authors and Affiliations

Paweł Pyrzanowski
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Abstract

Dry electrostatic precipitators (ESPs) are widely used for purification of exhaust gases in industrial applications. Maintenance of their high efficiency depends primarily on periodical cleaning of the collecting electrodes (CEs). Dust removal (regeneration of CEs) is realized by inducing periodical vibrations of the electrodes. The paper presents results of vibration modelling of a system of CEs; the results were obtained by means of the finite element method, the hybrid finite element method, the finite strip method and a model formulated using Abaqus. Numerical results are compared with those obtained from experimental measurements. Conclusions concerning numerical effectiveness and exactness of the methods are formulated and reasons for differences are discussed.

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Authors and Affiliations

Iwona Adamiec-Wójcik
Andrzej Nowak
Stanisław Wojciech
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Abstract

The work presents investigation on the water droplet impingement at a substrate with three different surface coating. The experiments are carried out for two temperatures of the surface: 23ºC (room temperature) and -10ºC. The water droplet contact is recorded via ultra-fast camera and simultaneously via fast thermographic camera. The wetting properties are changing for subzero temperatures of substrates.

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Bibliography

[1] A. Alizadeh,V. Bahadur, S. Zhong,W. Shang, R. Li, J. Ruud, M.Yamada, L. Ge, A. Dhinojwala, and M. Sohal. Temperature dependent droplet impact dynamics on flat and textured surfaces. Applied Physics Letters, 100(11):111601, 2012. doi: 10.1063/1.3692598.
[2] M. Nosonovsky and V. Hejazi. Why superhydrophobic surfaces are not always icephobic. ACS Nano, 6(10):8488–8491, 2012. doi: 10.1021/nn302138r.
[3] K.K. Varanasi, T. Deng, M. Hsu, and N. Bhate. Hierarchical superhydrophobic surfaces resist water droplet impact. In Technical Proceedings of the 2009 NSTI Nanotechnology Conference and Expo, Houston, Texas, USA, 3-7 May 2009. Nano Science and Technology Institute. http://hdl.handle.net/1721.1/64767.
[4] L. Mishchenko, B. Hatton, V. Bahadur, J.A. Taylor, T. Krupenkin, and J. Aizenberg. Design of ice-free nanostructured surfaces based on repulsion of impacting water droplets. ACS Nano, 4(12):7699–7707, 2010. doi: 10.1021/nn102557p.
[5] R. Ramachandran, K. Sobolev, and M. Nosonovsky. Dynamics of droplet impact on hydrophobic/icephobic concrete with the potential for superhydrophobicity. Langmuir, 31(4):1437–1444, 2015. doi: 10.1021/la504626f.
[6] T. Bobinski, G. Sobieraj, K. Gumowski, J. Rokicki, M. Psarski, J. Marczak, and G. Celichowski. Droplet impact in icing conditions – the influence of ambient air humidity. Archives of Mechanics, 66(2):127–142, 2014. http://am.ippt.pan.pl/index.php/am/article/view/v66p127.
[7] R. Rioboo, M. Marengo, and C. Tropea. Time evolution of liquid drop impact onto solid, dry surfaces. Experiments in Fluids, 33(1):112–124, 2002. doi: 10.1007/s00348-002-0431-x.
[8] N. Laan, K.G. de Bruin, D. Bartolo, C. Josserand, and D. Bonn. Maximum diameter of impacting liquid droplets. Physical Review Applied, 2(4):044018, 2014. doi: 10.1103/PhysRevApplied.2.044018.
[9] B.B.J. Stapelbroek, H.P. Jansen, E.S. Kooij, J.H. Snoeijer, and A. Eddi. Universal spreading of water drops on complex surfaces. Soft Matter, 10(15):2641–2648, 2014. doi: 10.1039/c3sm52464g.
[10] M. Remer, M. Psarski, K. Gumowski, J. Rokicki, G. Sobieraj, M. Kaliush, D. Pawlak, and G. Celichowski. Dynamic water contact angle during initial phases of droplet impingement. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 508:57–69, 2016. doi: 10.1016/j.colsurfa.2016.08.028.
[11] C.T. Crowe. Multiphase Flow Handbook, volume 59 of Mechanical and Aerospace Engineering Series. CRC Press, 2005.
[12] C. Stanley, R. Jackson, N. Karwa, and G. Rosengarten. The effects of surface wettability on droplet fingering. In The Proceedings of the 19th Australasian Fluid Mechanics Conference, Melbourne, Australia, 8-11 December 2014. Paper No. 49.
[13] A. Latka, A. Strandburg-Peshkin, M.M. Driscoll, C.S. Stevens, and S.R. Nagel. Creation of prompt and thin-sheet splashing by varying surface roughness or increasing air pressure. Physical Review Letters, 109(5):054501, 2012. doi: 10.1103/PhysRevLett.109.054501.
[14] T.G. Myers, J.P.F. Charpin, and C.P. Thompson. Slowly accreting ice due to supercooled water impacting on a cold surface. Physics of Fluids, 14(1):240–256, 2002. doi: 10.1063/1.1416186.
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Authors and Affiliations

Tomasz Lizer
1
Michał Remer
1
Grzegorz Sobieraj
1
Maciej Psarski
2
Daniel Pawlak
2
Grzegorz Celichowski
2

  1. Institute of Aeronautics and Applied Mechanics, Warsaw University of Technology, Poland.
  2. Faculty of Chemistry, Department of Materials Technology and Chemistry, University of Lodz, Poland.
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Abstract

Condition monitoring in a centrifugal pump is a significant field of study in industry. The acoustic method offers a robust approach to detect cavitations in different pumps. As a result, an acoustic-based technique is used in this experiment to predict cavitation. By using an acoustic technique, detailed information on outcomes can be obtained for cavitation detection under a variety of conditions. In addition, various features are used in this work to analyze signals in the time domain using the acoustic technique. A signal in the frequency domain is also investigated using the fast Fourier method. This method has shown to be an effective tool for predicting future events. In addition, this experimental investigation attempts to establish a good correlation between noise characteristics and cavitation detection in a pump by using an acoustic approach. Likewise, it aims to find a good method for estimating cavitation levels in a pump based on comparing and evaluating different systems.
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Authors and Affiliations

Ahmed Ramadhan Al-Obaidi
1
ORCID: ORCID

  1. Faculty of Engineering, Department of Mechanical Engineering, Mustansiriyah University, Baghdad, Iraq
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Abstract

This article deals with the design of slewing rings (slewing bearings). A fully parametric, 3D virtual model of a ball slewing ring with four-point contact was created in the PTC/Creo Parametric CAD system. This model was subsequently used for finite-element analysis using Ansys/Workbench CAE software. The purpose of the FEM analysis was to determine the axial stiffness characteristics. Results of FEM analysis were experimentally verified using a test bench. At the end of the article, we present the nomograms of the deformation constant for different pitch diameters, rolling element diameters and contact angles.
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Bibliography

  1.  Y. Guo and R.G. Parker, “Stiffness matrix calculation of rolling element bearings using a finite element/contact mechanics model”, Mech. Mach. Theory 51, 32–45 (2012).
  2.  G. Chen and H. Wang, “Contact stress and radial stiffness of a cylindrical roller bearing with corrected roller generator”, Trans. Can. Soc. Mech. Eng. 40(5), 725–738 (2016).
  3.  L. Kania, R. Pytlarz, and S. Spiewak, “Modification of the raceway profile of a single-row ball slewing bearing”, Mech. Mach. Theory 128, 1–15 (2018).
  4.  R. Skyba, S. Hrček, L. Smetanka, and M. Majchrák, “Stiffness analysis of slewing bearings”, IOP Conf. Ser: Mater. Sci. Eng. 393, 012060 (2018).
  5.  P.P. Hou, L.Q. Wang, and Q.Y. Peng, “Vibration analysis of ball bearing considering waviness under high speed and an axial load”, Bull. Pol. Acad. Sci. Tech. Sci. 68(3), 517–527 (2020).
  6.  P. Ding, H. Wang, Y.F. Dai, J. Chen, H. Zhang, and F.Z. Sun, “MDCCS Based Multistage Life Prediction of Slewing Bearing with a Novel Performance Description: an Improved Variational Mode Decomposition Approach”, Exp. Tech. 43, 341–358 (2019).
  7.  Y. Zhang, B. Fang, L. Kong, and Y. Li, “Effect of the ring misalignment on the service characteristics of ball bearing and rotor system”, Mech. Mach. Theory 151, 103889 (2020).
  8.  V.S. Nagarajan, V. Kamaraj, and S. Sivaramakrishnan, “Geometrical sensitivity analysis based on design optimization and multiphysics analysis of PM assisted synchronous reluctance motor”, Bull. Pol. Acad. Sci. Tech. Sci. 67(1), 155–163 (2019).
  9.  E. Kurvinen, J. Sopanen, and A. Mikkola, “Ball bearing model performance on various sized rotors with and without centrifugal and gyroscopic forces”, Mech. Mach. Theory 90, 240−260 (2015).
  10.  G. Chen, G. Wen, Z. Xiao, and H. San, , “Experimental Study on Contact Force in a Slewing Bearing”, J. Tribol. 140(2), 021402 (2018).
  11.  I. Heras, J. Aguirrebeitia, M. Abasolo, and I. Coria, “An engineering approach for the estimation of slewing bearing stiffness in wind turbine generators”, Wind Energy 22, 376–391 (2018).
  12.  T.J. Royston and I. Basdogan, “Vibration transmission through self-aligning (spherical) rolling element bearings”, J. Sound Vibr. 215, 997–1014 (1998).
  13.  F. Bogard, S. Murer, L. Rasolofondraibe, and B. Pottier, “Numerical determination of the mechanical stiffness of a force measurement device based on capacitive probes: Application to roller bearings”, J. Comput. Des. Eng. 4, 29–36 (2017).
  14.  T.L.H. Walford and B.J. Stone, “The measurement of the radial stiffness of rolling element bearings under oscillating conditions”, J. Eng. Mech. Eng. Sci.22, 175–181 (1980).
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  18.  P. He, Y. Wang, H. Liu, E. Guo, and H. Wang, ”Optimization design of structural parameters of single-row four-point contact ball slewing bearing”, J. Braz. Soc. Mech. Sci. Eng. 42, 291 (2020).
  19.  J. Brandlein, P. Eschmann, L. Hasbargen, and K. Weigand, Ball and roller bearings – theory, design and application, John Wiley&Sons Ltd., 2000.
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  22.  A.J. Muminovic, M. Colic, E. Mesic, and I. Saric, “Innovative design of spur gear tooth with infill structure”, Bull. Pol. Acad. Sci. Tech. Sci. 68(3), 477–483 (2020).
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Authors and Affiliations

Slavomir Hrcek
1
Robert Kohar
1
Jan Steininger
2

  1. University of Zilina, Faculty of Mechanical Engineering, Department of Design and Machine Elements, Slovak Republic
  2. University of Zilina, Institute of Competitiveness and Innovations, Slovak Republic
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Abstract

A cross-flow, tube and fin heat exchanger of the water – air type is the subject of the analysis. The analysis had experimental and computational form and was aimed for evaluation of radiative heat transfer impact on the heat exchanger performance. The main element of the test facility was an enlarged recurrent segment of the heat exchanger under consideration. The main results of measurements are heat transfer rates, as well as temperature distributions on the surface of the first fin obtained by using the infrared camera. The experimental results have been next compared to computational ones coming from a numerical model of the test station. The model has been elaborated using computational fluid dynamics software. The computations have been accomplished for two cases: without radiative heat transfer and taking this phenomenon into account. Evaluation of the radiative heat transfer impact in considered system has been done by comparing all the received results.

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Authors and Affiliations

Małgorzata Hanuszkiewicz-Drapała
Tomasz Bury
Katarzyna Widziewicz
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Abstract

The paper presents the effectiveness of waste heat recovery regenerators equipped with innovative ceramic matrix forming an integral part of a real glass furnace. The paper full description of the regenerators’ matrix structure with its dimensions, thermo-physical properties and operating parameters is included experimentally determined was the effectiveness of the regenerators has been descrbed using the obtained experimental data such as the operating temperature, gas flows as well as the gases generated during the liquid glass manufacturing process. The effectiveness values refer not only to the heating cycle when the regenerator matrix is heated by combustion gases but also to the cooling cycle in which the matrix is cooled as a result of changes in the direction of the flowing gas. On the basis of the determined effectiveness values for both cycles and measurement uncertainties it was possible, to calculate the weighted average efficiency for each of the regenerators.

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Authors and Affiliations

Grzegorz Wołkowycki
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Abstract

Any industrial process needs to work with the optimal operating conditions and thus the evaluation of their robustness is a critical issue. A modeling of a laboratoryscale wire-to-plane two stages electrostatic precipitator for guiding the identification of the set point, is presented this in paper. The procedure consists of formulating recommendations regarding the choice of optimal values for electrostatic precipitation. A twostages laboratory precipitator was used to carry out the experiments, with samples of wood particles of average granulometric size 10 μm. The parameters considered in the present study are the negative applied high voltage of the ionization stage, the positive voltage of the collection stage and the air speed. First, three “one-factor-at-a-time” experiments were performed followed by a factorial composite design experiments, based on a two-step strategy: 1) identify the domain of variation of the variables; 2) set point identification and optimization of the process.
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Authors and Affiliations

Djelloul Berrached
Amar Tilmatine
Farid Miloua
Malika Bengrit
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Abstract

The aim of the study was to examine the efficiency of the thermal wave type adsorption refrigerating equipment working on a pair of activated carbon and methanol. Adsorption units can work in trigeneration systems and in applications driven by waste heat. They can be built also as a part of hybrid sorption-compressor systems, and they are very popular in solar refrigeration systems and energy storage units. The device examined in this study operates in a special mode called thermal wave. This mode allows to achieve higher efficiency rates than the normal mode of operation, as a significant contributor to transport heat from one to the other adsorber. To carry out the experiment a test bench was built, consisting of two cylindrical adsorbers filled with activated carbon, condenser, evaporator, oil heater and two oil coolers. Thermal oil circulation was responsible for providing and receiving heat from adsorbers. In order to perform the correct action a special control algorithm device was developed and implemented to keep the temperature in the evaporator at a preset level. The experimental results show the operating parameters changes in both adsorbers. Obtained COP (coefficient of performance) for the cycle was 0.13.

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Authors and Affiliations

Artur Rusowicz
Andrzej Grzebielec
Rafał Laskowski
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Abstract

The effects of filling the core box cavity and sand compaction in processes of core production by blowing methods (blowing, shooting)

depend on several main factors. The most important are: geometrical parameters of cavity and complexity of its shape, number,

distribution and shape of blowing holes feeding sands as well as the venting of a technological cavity. Values of individual parameters are

selected according to various criteria, but mostly they should be adjusted to properties of the applied core sand.

Various methods developed by several researchers, including the authors own attempts, allow to assess core sands properties on the basis

of special technological tests projecting the process into a laboratory scale. The developed criteria defining a degree or a filling ability

factor provide a better possibility of assessing the core sand behavior during flowing and core box filling, which indicate the value and

structure of the obtained compacting decisive – after hardening – for strength and permeability. The mentioned above aspects are analyzed

– on the basis of authors’ own examinations - in the hereby paper.

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Authors and Affiliations

R. Dańko
J. Dańko
M. Skrzyński
A. Burbelko
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Abstract

Theoretical problems concerning the determination of work parameters of the two-phase sand-air stream in the cores making process by blowing methods as well as experimental methods of determination of the main and auxiliary parameters of this process decisive on the cores quality assessed by the value and distribution of their apparent density are presented in the paper. In addition the results of visualisations of the core-box filling with the sand-air stream, from the blowing chamber, obtained by the process filming by means of the quick-action camera are presented in the paper and compared with the results of simulation calculations with the application of the ProCast software.
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Authors and Affiliations

J. Danko
R. Dańko
M. Skrzyński
A. Burbelko
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Abstract

Materials and their development process are highly dependent on proper experimental testing under wide range of loading within which high-strain rate conditions play a very significant role. For such dynamic loading Split Hopkinson Pressure Bar (SHPB) is widely used for investigating the dynamic behavior of various materials. The presented paper is focused on the SHPB impulse measurement process using experimental and numerical methods. One of the main problems occurring during tests are oscillations recorded by the strain gauges which adversely affect results. Thus, it is desired to obtain the peak shape in the incident bar of SHPB as “smooth” as possible without any distortions. Such impulse characteristics can be achieved using several shaping techniques, e.g. by placing a special shaper between two bars, which in fact was performed by the authors experimentally and subsequently was validated using computational methods.

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Authors and Affiliations

Paweł Baranowski
Roman Gieleta
Jerzy Malachowski
Krzysztof Damaziak
Lukasz Mazurkiewicz
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Abstract

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.

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Authors and Affiliations

A. Sawicki
W. Świdziński
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Abstract

In the paper, the author presents experimental analysis of propagation of plastic zones in two-dimensional models with different stress concentrators. The experimental tests were carried out by photoelastic coating method on duralumin stripes loaded by tensile stresses. For various levels of loading, the photographs of isochromatic pattern were taken under loading and after removing loading. On the basis of isochromatic pattern recorded for loaded models, the boundaries of plastic zones were determined using the Treska-Coulomb yield condition. The isochromatic pattern taken for the unloaded, but previously partly plastified elements, show the picture of the residual strain remaining in the material. A discussion of the results is presented.

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Authors and Affiliations

Barbara Kozłowska
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Abstract

In the paper, author presents the analysis of the elastic-plastic residual stresses and the boundaries of plastic zones in two-dimensional model with central circular hole. The experimental testing was carried out by photoelastic coating method. The duralumin model was loaded within the overelastic range by uniformly distributed tensile stresses. For various levels of loading, the photographs of isochromatic pattern were taken. The residual stresses along the axis of symmetry perpendicular to the stretching direction were calculated by the characteristics method, using multisectional schematization of ϭ-ε relation for the material. The boundaries of plastic zones in the loaded model were obtained on the basis of the Treska-Coulomb yield condition directly from the isochromatic pattern. The analysis and discussion of the test results is presented.

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Authors and Affiliations

Barbara Kozłowska
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Abstract

The rigid finite element method (RFEM) has been used mainly for modelling systems with beam-like links. This paper deals with modelling of a single set of electrodes consisting of an upper beam with electrodes, which are shells with complicated shapes, and an anvil beam. Discretisation of the whole system, both the beams and the electrodes, is carried out by means of the rigid finite element method. The results of calculations concerned with free vibrations of the plates are compared with those obtained from a commercial package of the finite element method (FEM), while forced vibrations of the set of electrodes are compared with those obtained by means of the hybrid finite element method (HFEM) and experimental measurements obtained on a special test stand.

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Bibliography

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Authors and Affiliations

Iwona Adamiec-Wójcik
Andrzej Nowak
Stanisław Wojciech

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