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1

Examination of the deformation of an animal overpass soil-steel structure by means of geodetic measurements

Machelski Czesław

Roads and Bridges - Drogi i Mosty

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2022

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Vol. 21, no. 2

133--149

EN

The algorithm presented in this paper processes data in the form of the coordinates of points located on the shell’s circumferential section, obtained from geodetic measurements. The change in curvature is a geometric parameter used to study the deformation of the shell in a corrugated steel buried structure and to estimate the bending moment and hence the normal stress in the corrugated plate. The results of exemplary calculations of the analysed structure show that places with extreme values can be determined in this way. For this purpose a dense grid of measuring points needs to be created using precision land surveying. For stress estimation it is essential to correct the geodetic measurements base since the points in the initial measurement do not lie on the circular sector used as a reference line for determining the deformation of the shell.

PL

Przedstawiony w pracy algorytm dotyczy przetwarzania danych w postaci współrzędnych punktów pasma obwodowego powłoki, uzyskanych z pomiarów geodezyjnych. Parametrem geometrycznym wykorzystywanym w pracy do badania deformacji powłoki w obiekcie jest zmiana krzywizny. Służy ona do szacowania momentu zginającego, a stąd – naprężenia normalnego w blasze falistej. Z rezultatów podanych w przykładach obliczeń analizowanej konstrukcji wynika możliwość określania miejsc o wartościach ekstremalnych. Do tego celu niezbędna jest gęsta siatka punktów pomiarowych utworzona z wykorzystaniem techniki geodezji precyzyjnej. Istotne znaczenie w szacowaniu naprężeń ma korekta geodezyjnej bazy pomiarowej. Wynika to z faktu, że punkty w pomiarze początkowym nie leżą na wycinku okręgu jako linii odnoszącej, wykorzystywanej do określenia deformacji powłoki.

2

Zastosowanie cyfrowej korelacji obrazu w badaniach elementów żelbetowych

Tworzewski Paweł

Przegląd Budowlany

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2022

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R. 93, nr 7-8

103--106

PL

W artykule przedstawiono możliwości wykorzystania cyfrowej korelacji obrazu (Digital Image Correlation), a dokładniej systemu ARAMIS SRX w badaniach elementów żelbetowych. Przykładowe pomiary wykonano dla belki żelbetowej poddanej obciążeniu do zniszczenia. Obejmują one przemieszczenia, odkształcenia oraz zarysowanie na wybranych obszarach. Opisano również zastosowaną wersję systemu ARAMIS, zmiany i nowe funkcje wprowadzone względem starszych wersji.

EN

The article presents using of Digital Image Correlation, and more specifically the ARAMIS SRX system, in the research of reinforced concrete elements. Exemplary measurements were made for a reinforced concrete beam subjected to a load to failure. New and old version of the ARAMIS system was described, as well as its changes and new functions introduced in relation to older versions.

3

Rheological properties of elastic-visco-plastic liquid

Dadash-Zade Mirza A., Aliyev Inglab N.

Nafta-Gaz

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2022

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R. 78, nr 11

801--804

EN

A model for the motion of a compressible elastic-viscous-plastic fluid in a round pipe is proposed. The main indicators of the flow, volume flow and speed are obtained. Numerous hydrodynamic processes are associated with the properties of liquids. It is known that the mechanical and physical properties of liquids can be described by various models. Various models have been proposed that partially describe the processes of hydromechanics. The proposed model makes it possible to qualitatively describe the deformation processes that occur in various systems. To describe a closed theory of motion of a continuous medium and, in particular, between stress and strain, it is necessary to have a mechanical model. From the literature analysis it is known that there are simple models, which include elastic, viscous and plastic. At the same time, it should be noted that the mechanical model partially shows the mechanical state of the elastic body in the form of Hooke's law. Practice shows that there are more complex liquids that do not obey this law. One of these fluids is an elastic-viscousplastic fluid. In this work, a model is proposed that describes the elastic-viscous-plastic properties of liquids, which sequentially connects the elastic and viscous-plastic elements. For such a medium, the total resistance will be the sum of the stress corresponding to the elastic deformation and the stress caused by the viscous-plastic resistance. Based on the proposed model, an equation is obtained taking into account the coefficient of volumetric elastic expansion, and an equation is obtained for determining the velocity distribution over the pipe section and volume flow for a given liquid. Calculations have shown that with an increase in compressibility, the flow rate of the liquid partially increases, which in some practical cases produces a positive effect.

PL

W artykule zaprezentowano model ruchu ściśliwej cieczy sprężysto-lepkoplastycznej w rurze o przekroju okrągłym. Uzyskano główne wskaźniki przepływu, przepływu objętościowego i szybkości. Liczne procesy hydrodynamiczne są związane z właściwościami cieczy. Wiadomo, że właściwości mechaniczne i fizyczne cieczy można opisać za pomocą różnych modeli. Zaproponowano modele, które częściowo opisują procesy mechaniki cieczy. Przedstawiony model umożliwia jakościowy opis procesów odkształcenia zachodzących w różnych systemach. Model mechaniczny jest konieczny do opisania zamkniętej teorii ruchu ośrodka ciągłego, w szczególności pomiędzy naprężeniem i odkształceniem. Z analizy literatury wiadomo, że istnieją proste modele obejmujące ciecze sprężyste, lepkie i plastyczne. Należy jednocześnie zauważyć, że model mechaniczny częściowo przedstawia stan mechaniczny ciała sprężystego, wykorzystując prawo Hooke’a. Praktyka pokazuje, że istnieją ciecze bardziej złożone, niezachowujące się zgodnie z tym prawem. Jednym z takich płynów jest płyn sprężysto-lepkoplastyczny. W niniejszej pracy zaproponowano model opisujący właściwości sprężysto-lepkoplastyczne cieczy, który sekwencyjnie łączy elementy sprężyste i lepkoplastyczne. W przypadku takiego ośrodka opór całkowity jest sumą naprężenia odpowiadającego odkształceniu sprężystemu i naprężenia spowodowanego przez opór lepkoplastyczny. Na podstawie zaproponowanego modelu uzyskano równanie uwzględniające współczynnik objętościowej rozszerzalności sprężystej, a także uzyskano równanie do określenia rozkładu szybkości na przekroju rury oraz przepływu objętościowego dla danej cieczy. Obliczenia pokazały, że ze wzrostem ściśliwości szybkość przepływu cieczy częściowo wzrasta, co w pewnych praktycznych przypadkach daje pozytywny efekt.

4

Wizualne zmiany na elewacjach wentylowanych z okładzinami włóknisto-cementowymi

Kopyłow Ołeksij, Schabowicz Krzysztof

Materiały Budowlane

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2022

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nr 12

6--9

PL

Podczas eksploatacji elewacji wentylowanych z okładzinami z płyt włóknisto-cementowych często uwidoczniają się zmiany w postaci przebarwień i w wielu przypadkach towarzyszą im deformacje okładzin. Czy zmiany te mają charakter wyłącznie estetyczny i czy wpływają na właściwości użytkowe systemu elewacyjnego? Przeprowadzone badania laboratoryjne dają podstawy do stwierdzenia, że wraz ze zmianami wizualnymi zachodzą zmiany strukturalne oraz wytrzymałościowe w okładzinach, które mogą mieć istotny wpływ na właściwości techniczno-użytkowe systemów elewacyjnych, w tym bezpieczeństwa użytkowania.

EN

During the exploitation on fiber-cement cladings of ventilated facades systems sometimes are visible changes in the form of discoloration. Discoloration is often accompanied by deformation of the cladding. Are these changes aesthetic and do they also have an impact on the performance properties of the façade system? The laboratory tests give grounds to state that along with the visual changes, structural and strength changes in the claddings occur which changes may have a significant impact on the technical and operational properties of facade systems, including the safety of use.

5

The influence of loading rate on the mechanical behavior and energy evolution characteristics of hard and soft rock under triaxial compression

Deng Jihui, Chen Chao, Wu Xiaoning

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 3

495--508

EN

To investigate the influence of loading rate and confining pressure on the mechanical behavior and energy evolution characteristics of hard and soft rock, high strength sandstone and low strength granite were subjected to triaxial compression tests with different loading rates. The results show that significant differences exist in the stress-strain curves for sandstone and granite. The confining pressure has a significant effect on the stress-strain curve, while the loading rate has a smaller effect on the stress-strain curve. As the confining pressure increases, the peak axial strain, peak axial stress, total energy, elastic energy and dissipated energy of sandstone and granite increase, the proportion of dissipated energy to total energy of sandstone and the proportion of elastic energy to total energy of granite are reduced. As the loading rate goes up, the peak axial stress, total energy and elastic energy increase in both sandstone and granite. The ultimate failure pattern of sandstone is a typical single inclined plane shear failure, while the ultimate failure pattern of granite consists of a single inclined plane shear failure and a vertical split failure. The loading rate has no significant effect on the macroscopic failure pattern, the elastic and dissipated energies are proportional to the total energy of sandstone and granite.

6

Development of Fiber-Optic Sensors System, Based on Fiber Bragg Gratings

Kalizhanova Aliya, Kunelbayev Murat, Wojcik Waldemar, Kozbakova Ainur, Aitkulov Zhalau, Malikova Feruza

Journal of Ecological Engineering

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2022

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Vol. 23, nr 10

98--106

EN

An article herein considers the development of a fiber-optic sensor system, based on fiber Bragg gratings. Presently, fiber-optic sensors has become world-widely known amongst sensor technologies, used for monitoring engineering and construction structures. The work is linked with developing the system from fiber-optic sensors on the basis of fiber optic gratings, its characteristics, deformation behavior and temperature, acting at fiber Bragg grating by means of computer modeling. The research is focused at the analysis of characteristics and deformation and temperature behavior of fiber-optic Bragg sensor. Fiber-optic Bragg sensor with tilted grating is used for measuring deformation of the object, the strength of which is changed, dependent on the applied force, as well, for measuring and detecting any temperature deviations, influencing at fiber Bragg grating, which might bring to fire and accidents. In the research, simulation modeling there was made in the MATLAB (Simulink) software.

7

Most Uniwersytecki w Bydgoszczy. Teoretyczne podstawy decyzji o wyłączeniu obiektu z ruchu

Żółtowski Krzysztof, Binczyk Mikołaj, Kalitowski Przemysław

Inżynieria i Budownictwo

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2022

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R. 78, nr 1-2

25--30

PL

W artykule przedstawiono ogólny opis konstrukcji podwieszonego mostu Uniwersyteckiego nad rzeką Brdą w Bydgoszczy. Opisano również prace eksperckie dotyczące oceny nośności konstrukcji. W wyniku badań i analiz obiekt został uznany za niebezpieczny dla użytkowników i wycofany z eksploatacji. W artykule przedstawiono zasadnicze przesłanki, które doprowadziły zarządcę do podjęcia głównych decyzji i postępowania naprawczego.

EN

The paper presents a general description of the cable-stayed structure of the University Bridge over the Brda River in Bydgoszcz. A report on expert work on the assessment of the load capacity of the structure is also presented. As a result of research and analysis, the University Bridge has been recognized as dangerous for users and has been taken out of service. The paper presents the main premises that led to the main decisions and rehabilitation procedure.

8

Tensile fault dislocation in an irregular-layered elastic half-space

Savita, Sahrawat Ravinder Kumar, Malik Meenal

International Journal of Applied Mechanics and Engineering

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2022

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Vol. 27, no. 3

171--198

EN

In the present paper, an analytical solution for the static deformation of a two dimensional model consisting of an infinite homogeneous isotropic elastic layer of uniform thickness placed over an irregular isotropic elastic half-space due to movement of a long tensile fault has been obtained. The rectangular shaped irregularity is assumed to be present in the lower half-space and assuming that the fault lies in the elastic layer at a finite depth say ’h’ to the upper surface of the layer. For numerical computation, the expressions of displacements and stresses are calculated by using Sneddon’s method and the effect of source depth and irregularity on the displacements and stresses has been investigated graphically.

9

Zgrzewanie tarciowe z przemieszaniem blach cienkościennych z zastosowaniem podgrzewania

Ochałek Krzysztof

Hutnik, Wiadomości Hutnicze

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2022

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Vol. 89, nr 1

10--13

PL

W pracy przedstawiono podstawowe informacje na temat zgrzewania tarciowego z przemieszaniem. Skupiono się na problemie, jakim są występujące podczas zgrzewania odkształcenia cienkościennych blach ze stopu 2024 T351. W celu zniwelowania deformacji zaprojektowano i wykonano uchwyt z płytą podgrzewającą elementy zgrzewane. Zabieg podgrzewania zgrzewanych blach ma na celu obniżenie naprężeń chwilowych, a co za tym idzie zmniejszenie ich a wykonywano przy tych samych parametrach.

EN

The paper depicts basic information concerning Friction Stir Welding. The main focus revolves around a problem which is deformation of thin-walled plates made out of 2024 T351 alloy which occurs when the plates are welded. In order to reduce these deformations a mount with panel that heats up welded elements has been designed and produced. The procedure of heating up welded plates intends to reduce temporary tensions and as a consequence of that it also reduces the deformation of the plates. All tests of welding were conducted under the same parameters.

10

Crustal deformation of the Central Indian Ocean, south of Sri Lanka as inferred from gravity and magnetic data

Kumar Sistla Ravi

Geology, Geophysics and Environment

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2022

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Vol. 48, no. 2

89--110

EN

Bathymetry, gravity, and magnetic data across the Central Indian Ocean Basin (CIOB) along a WE track between 5°N to 1°N latitudes and 77°E to 90°E longitudes are used to identify crustal deformation due to tectonic features such as the Comorin Ridge, 85°E ridge, Ninety East Ridge, and major fracture zones. The tectonic features were interpreted along the North Central Indian Ocean using 2D gravity modelling to understand the origin and tectonic activity of the subsurface features. The Comorin Ridge is coupled with gravity anomalies with small amplitude varying 25–30 mGal in comparison with the ridge relief which suggests that the ridge is compensated at deeper depths. The focus of the present study is to prepare a reasonable crustal model of the Central Indian Ocean using gravity and magnetic data. The crustal depths of the Central Indian Ocean Basin (CIOB) determined from gravity data using the spectral method are compared with the 2D gravity modelling results. It has been observed that the crustal depths obtained from the Spectral method are in good correlation with results obtained from 2D gravity modelling. The average basement depths for the profiles were obtained as ~5 km and perhaps deviated approximately 1–2 km from the mean. In the case of curie isotherm, the crustal depths vary 9–12 km for all magnetic profiles which may indicate deformation.

11

Coupling Characteristics of Needles and Backing Cloth During the Carpet Tufting Process

Xu Yang, Huang Shuang, Sheng Xiaowei, Zhijun Sun

Fibres & Textiles in Eastern Europe

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2022

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Nr 3 (151)

9--17

EN

Focusing on the needle and backing cloth on a tufting machine type DHG801D-200, a finite element model was built using ABAQUS/Explicit software. The tufting processes, in which the individual tufting needles and 1/10 needle modules puncture the polypropylene woven and nonwoven fabrics (hot-air bonded nonwoven and thermo-calender bonded nonwoven), were simulated, respectively. Finally, the needle forces were estimated, and the deformations and stress field distribution of the backing cloth at different times were analysed.

12

Hydrogen Dilatation of V-Based Composite Membranes

Panichkin Alexander, Mamaeva Axaule, Kenzhegulov Aidar, Karboz Zhanar

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

767--772

EN

One of the problems limiting the use of vanadium as hydrogen permeable membranes is its high dilatation upon hydrogen dissolution in it. The information available for the dilatation coefficient value (Δυ/Ω) is contradictory, experimental information on the hydrogen solubility in vanadium within 100-1000 kPa at from 250 to 700°С is very limited. It does not enable to calculate the membrane dilatation. The article contains the measuring results for dilatation of strips made of vanadium foil 100 μm thick in a hydrogen atmosphere in the pressure range from 75 to 1000 kPa, temperatures from 250 to 700°С. The dilatation coefficient (Δυ/Ω) of polycrystalline vanadium was calculated based on the data obtained for dilatation and data previously published for the hydrogen concentration in the α-solid solution at 400°С. It is 0.165. Isobars for the temperature dependence of the hydrogen concentration in vanadium are calculated and constructed using the dilatation measuring results and the dilatation coefficient values. These data are agreed with theoretical and experimental data published previously. The limiting change in concentration and linear dimensions over the cross section of a hydrogen-permeable membrane from V was estimated at various temperatures and operating pressures at the membrane outlet based on the isobars plotted for temperature dependences of the CH/V. The conclusions are made on the optimal working conditions of Pd/V/Pd membranes when hydrogen is released from hydrogen-containing gas mixtures in accordance with Fick’s 1st law and data published previously for hydrogen concentration value at which solid hydrogen solutions in vanadium become brittle.

13

Finite element analysis of mechanical stress in in-wheel motor

Xu Jie

Archives of Electrical Engineering

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2022

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Vol. 71, nr 2

455--469

EN

When the in-wheel motor is working, it will be affected by gravity, centrifugal force and electromagnetic force. These three kinds of mechanical loads will affect the mechanical stress characteristics of the in-wheel motor, and then affect the reliability of the in-wheel motor structure. In order to understand the influence of the above loads on the mechanical stress of the in-wheel motor, this paper takes a 15-kW built-in permanent magnet in-wheel motor as the research object. Based on the establishment of the electromagnetic field and structure field coupling analysis model of the in-wheel motor, the mechanical stress of the in-wheel motor under different mechanical loads under rated and peak conditions are calculated and analyzed, and the influence of different mechanical loads on the stress and deformation of the in-wheel motor are studied. The research results show that, regardless of the rated operating condition or the peak operating condition, the in-wheel motor has the largest mechanical stress and deformation under the combined action of centrifugal force and electromagnetic force, and the smallest mechanical stress and deformation under the action of gravity only; under the same load (except for the case of gravity only), the stress and deformation of the in-wheel motor under the peak operating condition are larger than those under the rated operating condition; and the maximum stress and deformation of the in-wheel motor appear at the rotor magnetic bridge and the inner edge of the rotor, respectively, so the rotor is an easily damaged part of the in-wheel motor.

14

Experimental study on dynamic stability of rubber-cement composites by SHPB and high-speed slicing

Yang Rongzhou, Xu Ying, Chen Pei Yuan

Archives of Civil Engineering

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2022

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Vol. 68, nr 1

319--334

EN

Improper disposal of waste tires will not only bring environmental impact and safety risks but also cause a serious waste of resources. In the field of civil engineering materials, waste tire particles are used as a substitute for non-renewable aggregates to produce flexible rubber-cement composites (RCC). To explore the high-speed slicing stability of RCC, this test took normal cement mortar (NCM) and rubber cement mortar (RCM) as research objects. The SHPB tests with the same impact energy level and the high-speed slicing tests with a slice thickness range of about 1.4 mm ~ 4.4 mm were carried out. The results showed that NCM and RCM showed different stability differences in the process of high-speed slicing. In the case of ensuring the integrity of the slice, the minimum thickness of the slice can be better decreased with the increase of the rubber content. Finally, from the perspectives of split Hopkinson pressure bar (SHPB) test results and mesoscopic structure states, the essential reason for ensuring the stability of high-speed slicing lied in the improvement of rubber particles (dominant role) and pores on material deformation and flexible energy dissipation.

15

Analysis of deformation and forms of destruction of coating-substrate systems

Chronowska-Przywara Kinga

Tribologia

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2021

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nr 4

7--14

EN

The paper presents the results of fracture testing of a coating-substrate system subjected to a concentrated contact load and during a scratch test. A diamond indenter with rounding radii in the range 20-500 µm was used under the tests. Systems with CrN coatings in the range of 1 to 5 µm applied to austenitic steel X5CrNi18-10 were analysed. In the paper, the effect of coating thickness on deformation and fracture of the coating and substrate in the load range of 1 and 3 N is analysed. Cohesion and adhesion sites of the coating to the substrate were determined. Optical profilometer images, scanning microscope images, and Micro Combi Tester images – CSM Instruments were used to analyse Lc1, Lc2, and crack locations. It was observed that, as the indenter radius increases, cracks in the coating-substrate system develop at increasing loads. Average critical forces are also higher with indenters of 200–500 µm. In the case of indentation only, with the indenter’s radius of 500 um, it is 750 Nm for the thinnest 1 µm coating and 1750 Nm for the 5.2 µm coating.

PL

W artykule przedstawiono wyniki badań pękania układu powłoka–podłoże poddanych obciążeniu działającym w styku skoncentrowanym oraz podczas testu zarysowania. Do badań użyto diamentowego wgłębnika o promieniach zaokrąglenia z zakresu 20–500 µm. Analizowano układy z powłokami CrN w zakresie od 1 do 5 µm nałożone na stal austenityczną X5CrNi18-10. W artykule analizowano wpływ grubości powłok na deformacje i pękanie powłoki i podłoża w zakresie obciążenia 1 i 3 N. Wyznaczono miejsca kohezji i adhezji powłoki do podłoża. Do analizy Lc1, Lc2 oraz lokalizacji pęknięć użyto obrazów z profilometru optycznego, zdjęć z mikroskopu skaningowego i zdjęć z Micro Combi Testera – CSM Instruments. W wyniku przeprowadzonych badań zauważono, że wraz ze wzrostem promieniem zaokrąglenia wgłębnika, pęknięcia układu powłoka–podłoże powstają przy coraz większych obciążeniach. Średnie wartości sił krytycznych również jest większe przy stosowaniu wgłębników 200–500 µm. W przypadku samej indentacji przy promieniu wgłębnika 500 µm wynosi 1 µm, 750 Nm, natomiast dla powłoki 5,2 µm 1750 Nm.

16

Structure and metamorphism of the Dardania zone in the eastern part of Gjilan region (Kosovo)

Kutllovci Festim

Mining Science

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2021

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Vol. 28

93--102

EN

The Dardanian zone represents the western part of the Rhodope crystalline basement. This zone was structured and metamorphosed during the Hercynian and post Hercynian tectonic stages. The important aspects have been identified in the structure and metamorphism from this part of western Rhodopes. The geological setting of study region has clarified the most important aspects regarding: structural geology, deformation, tectonics, and metamorphism. The studied region represents an important node in the geology of Kosovo and beyond. In this region there is the border of the Vardar unit and the Serbo-North Macedonian tectonic unit (Dardania Massif). The Serbo-North Macedonian Massif (eastern part of Kosovo) structurally represents the upper part of Dacia and the innermost whole, compared to the Carpathian-Balkanids described above. The Crystalline belt of metamorphic rocks belongs to high-grade metamorphism. The rocks of the Upper Complex represent a volcano-sedimentary sequence that is metamorphosed only under greenschist facies conditions. The Lower Complex consisting of gneiss, micaschists and to a lesser extent amphibolites, quartzites, marbles and migmatites. The main event of the Hercynian tectonic period that structured the rocks forming in the Dardania zone is associated with the regional deformation D2. Its intensity is depending on the type of rocks, but it is noted an increase of the intensity from west to east. The associated schistosity S2(penetrating schistosity)is an axial plane schistosity of the isoclinals folds S0, S1. The schistosity S2 is homogenous, with an average strike direction of 345° and dip direction of 45°. The intersection lineation (L2) and the fold axis (B2) are very homogenous with the dip azimuth toward N (350°) and dip angle of 10°. The deformation D3 is associated with the crenulations of schistosity S3. The schistosity S3 represents the axial plan of the kink fold and crenulation. The schistosity S3 is very heterogeneous and it is difficult to arrive at conclusions regarding the average direction of this planar structure also to judge the kinematic aspects of the movement. Likewise, the axis of the crenulations B3 and L3 lineation represent relative heterogeneous linear structures. The deformation D4 is associated with the fracture schistosity S4. The schistosity S4 often show the axial plan of the open parallel folds. The schistosity S4 is homogenous with the range East–West with symmetric drop (in the N and S), by proving that we are dealing with a phase of deformation with an extensional tectonic regime (with the direction N–S).

17

Porównanie metod pomiarów konstrukcji na podstawie badań stropu słupowo-płytowego

Nykiel Damian

Inżynieria i Budownictwo

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2021

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R. 77, nr 8

397--400

PL

Porównano różne metody pomiarów odkształceń i przemieszczeń konstrukcji. Odkształcenia mierzono tensometrami elektrooporowymi i światłowodowymi, a przemieszczenia czujnikami indukcyjnymi, linkowymi oraz stosując system optycznej korelacji obrazu ARAMIS.

EN

Various methods of monitoring deformation and displacement of the structure were compared, based on the tests of the column-plate slab. Deformations were measured with electrofusion and fiber-optic strain gauges, and displacements with inductive and wire-line sensors and the ARAMIS optical.

18

Measuring Equivalent Cohesion Ceq of the Frozen Soils by Compression Strength using Kriolab Equipment

Lemenkov Vasiliy, Lemenkova Polina

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 2

63--84

EN

Current paper presents the results of the experimental analysis on permafrost uppermost soil samples with various physical properties (moisture, porosity) tested with varied external pressure and time. The aim of this work is to test properties of the soil samples intended for the construction of buildings, railways and objects of civil infrastructure by modeled external pressure, data visualization and analysis. Variations in the soil samples were studied by analysis of the equivalent soil cohesion (Ceq) in frozen soil samples. Methods include integrated application of the laboratory experiments, methods of the statistical data analysis and 3D plotting performed by the selected LaTeX packages. Laboratory experiments were performed using KrioLab equipment ‘Sharikovy Stamp PSH-1’. The 15 series of experiments have been tested. Models of the soil strength are graphically presented and statistically analyzed showing the results of the experiment.

19

Okresowe oceny stanu technicznego elewacji budynków Cz. 8. Elewacje wentylowane z płyt włóknisto-cementowych

Runkiewicz Leonard, Kopyłow Ołeksij, Sieczkowski Jan

Builder

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2021

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R.25, nr 2

25--31

PL

Elewacje wentylowane z płyt włóknisto-cementowych należą do najczęściej spotykanych rozwiązań wśród elewacji wentylowanych. Podobnie jak inne elewacje wentylowane, omawiany typ składa się z podkonstrukcji (rusztu), izolacji termicznej, szczeliny wentylacyjnej i okładziny z płyt włóknisto-cementowych. Elewacje wentylowane z okładzinami z włóknocementu są bardzo wrażliwe na błędy projektowe oraz wykonawcze. Poza tym wymagają przeprowadzania kontroli okresowych stanu technicznego w celu wykrycia na wczesnych etapach wszystkich anomalii oraz uszkodzeń, które mogą spowodować przyspieszone degradacje systemów elewacyjnych. W artykule przedstawiono zasady przeprowadzania ocen okresowych elewacji wentylowanych z okładzinami włóknisto-cementowymi, a także podstawowy zakres czynności pozwalających określić ich stan techniczny. Opisano również metody eksperckie pozwalające na diagnozowanie omawianych systemów elewacyjnych.

EN

Ventilated facades made of fiber-cement panels are the most common solutions among ventilated facades. Like other ventilated facades, the discussed type consists of: subframe systems, thermal insulation, ventilation air space and fiber-cement cladding. Ventilated facades with fiber-cement cladding are very sensitive to design and workmanship fals. In addition, they require reliable periodic inspections of the technical condition in order to identify at an early stage all anomalies and damages that may cause accelerated degradation of the facade system. The paper presents the principles of periodic assessments of ventilated facades with fiber-cement cladding and the basic scope of activities allowing to determine their technical condition. Also, expert methods are described that allow to diagnose the discussed facade systems.

20

Analysis of Fracture Mechanism of Cast Steel for Different States of Stress

Lachowski J., Borowiecka-Jamrozek J.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 2

29--34

EN

In this paper a plastic deformation and a damage evolution in low-carbon cast steel containing non-metallic inclusions are analysed experimentally and numerically. Two microstructures of the cast steel have been obtained after appropriate heat treatment. Tensile tests of smooth specimens and axisymmetric notched specimens have been performed. The notched specimens have the notch radii: 1 mm, 3 mm and 7 mm. Fractography of the specimens was carried out to observe fracture mechanisms. The mechanism depended on the stress state in the notched specimens. The fractography showed the existence of two fracture mechanisms: ductile failure and by shear. The process of the voids growth formed on the non-metallic inclusions was the process which included in the explanation of the damage mechanism. Modelling of deformation of the specimens has been used with the model suggested by Gurson, Tvergaard and Needleman. The model is implemented in the Abaqus finite element program. The computer simulation was performed using ABAQUS system. The computed output was compared with the experimental results obtained for specimens of the same shape.