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1

Study on failure modes and calculation method of the cast steel joint with branches in treelike structure

Chen Feng, Sun Yun, Sun Shuxuan, Song Da, Liu Yangbing

Archives of Civil Engineering

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2024

|

Vol. 70, nr 1

589--604

EN

The treelike structure links members and transfers loads via its solitary cast steel joint with branches. Therefore, the joint’s bearing capacity significantly affects the treelike structure’s stability, security, and economics. This paper utilized experimental verification and numerical modeling to examine the mechanical behavior of cast-steel joints with branches in the treelike structure under various loading conditions. Then, researchers investigated the failure process and mechanism of joints, and the three most common failure modes were outlined. Furthermore, the researchers proposed the bearing capacity calculation formula based on the common failure modes. The results show that the three common failure modes of the cast-steel joints with branches under different loading conditions are the failure in the joint core area under the axial load, the failure in the main pipe compression side under eccentric load, and the failure in the compression side of the single branch pipe root when the single branch pipe is under the uneven load. The suggested empirical calculation method can serve as a reference point for similar engineering practices design.

2

Experimental identification of the force and moment characteristic of symmetrically and non-symmetrically profiled annular seals

Kuhr Maximilian M. G., Pelz Peter F.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 6

art. no. e147062

EN

In modern turbomachinery, the performance and reliability is often limited by shaft vibrations induced by fluid film forces and moments of (i) plain or (ii) profiled annular seals. Therefore, these narrow annuli are mainly responsible for the overall system behaviour, i.e. safe operation and maintenance intervals. However, many studies focus only on the characteristics from the forces due to the translational motion, although the influence of the rotordynamic tilt and moment coefficients is well known. Therefore, these additional coefficients are much less researched. Especially, for profiled seals, the availability of reliable experimental data for validation purpose is rare. To overcome this fact, a test rig is operated at the Chair of Fluid Systems at the Technische Universität Darmstadt. The generic experiments presented here investigate the force and moment characteristic of plain, symmetrically profiled and non-symmetrically profiled annular seals within the relevant parameter range for turbulent flows in pumps. The investigations focus on the influence of the annulus length as well as the pressure difference across the annulus.

3

Krajobraz i jego ocena w ujęciu fenomenologicznym

Bonenberg Wojciech

Zeszyty Naukowe Politechniki Poznańskiej. Architektura, Urbanistyka, Architektura Wnętrz

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2022

|

Z. 8

31--41

PL

Artykuł ma charakter eksperymentu okazjonalnego prezentującego fenomenologiczne podejście do badań krajobrazu oraz przykład krytycznej ich oceny z punktu widzenia wartości, jakie badania te wnoszą do dyscypliny naukowej architektura i urbanistyka.

EN

The article has the character of an occasional experiment presenting a phenomenological approach to landscape research. Particular attention has been paid to the usefulness of such methodological instruments for assessing landscape context in architecture and urban planning

4

Model of the city

Słyk Jan

Przestrzeń i Forma

|

2022

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nr 50

55--64

EN

The design and development of cities is the most complicated phenomenon in the domain of shaping space. It is the result of planned human activities related to land parcellation, building infrastructure, establishing safety rules, creating a friendly scale and aesthetics of public spaces. It is also the result of spontaneous processes that take place without strict control. It is influenced by economy, demography, environmental factors, as well as wars, conflicts, and competition between entities. In architecture, it is possible to build knowledge and competences by performing tests on a 1:1 scale. Although expensive and difficult, it sometimes brings the desired results and opens the perspective to new design techniques. In urban planning, the subject of creative activities is too complex to test final solutions. The time from design to implementation is too long to use your own experience even indirectly. The only way to test urban ideas in the conceptual phase is to create models. Both geometric and social features could be represented. The most perfect contemporary models attempt to comprise many processes of city functioning, including spontaneous activities conditioned by external and internal factors.

PL

Proces powstawania i rozwoju miast jest najbardziej skomplikowanym zjawiskiem w obszarze zagadnień przestrzennych. Jest wynikiem planowych działań człowieka dotyczących podziału gruntu na parcele, budowy infrastruktury, tworzenia zasad bezpieczeństwa, kreowania przyjaznej skali i estetyki wnętrz publicznych. Jest także rezultatem spontanicznych procesów toczących się bez ścisłej kontroli. Mają na nie wpływ ekonomia, demografia, czynniki środowiskowe, a także wojny, spory, rywalizacja podmiotów. W architekturze możliwe jest budowanie wiedzy i kompetencji poprzez wykonywanie prób w skali 1:1. Choć kosztowne i trudne, przynosi niekiedy pożądane rezultaty i otwiera drogę ku nowym technikom projektowania. W urbanistyce, przedmiot działań twórczych jest zbyt złożony, aby testować gotowe rozwiązania. Czas upływający od projektu do realizacji jest zbyt długi, aby nawet pośrednio korzystać z własnych doświadczeń przy kolejnych próbach. Jedynym sposobem testowania rozwiązań urbanistycznych w fazie koncepcyjnej jest tworzenie modeli. Reprezentowane są w nich zarówno cechy geometryczne jak i społeczne. Najdoskonalsze współczesne modele starają się uwzględniać wiele procesów funkcjonowania miast, w tym również procesy spontaniczne uwarunkowane przez czynniki zewnętrzne i wewnętrzne.

5

Quantitative assessment of the influence of plasma hardfacing parameters on the metallurgical melting of an austentic steel coating with a substrate material made of C45 steel

Bazychowska Sylwia, Starosta Robert, Dudzik Krzysztof

Journal of KONBiN

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2022

|

Vol. 52, iss. 3

27--51

EN

In this paper, based on a quantitative analysis of the parameters of plasma hardfacing of C45 steel with CastoMag 45554S wire, an optimisation of the hardfacing process parameters has been carried out. Experimental researches were carried out on the basis of an orthogonal plan, and the optimum hardfacing parameters, e.g.: intensity, voltage, wire feeding speed, were determined by the multiple regression method and the Taguchi method. It was found that the main current of the plasma arc had the greatest influence on the value of the fusion index. The highest S/N value was obtained for the following parameters: I = 120 A, U = 31 V, vn = 0.75 m/min, vd = 3.9 m/min, z = 12 mm.

PL

W oparciu o ilościową analizę parametrów napawania plazmowego stali C45 drutem CastoMag 45554S dokonano optymalizacji parametrów procesu napawania. Badania realizowano na podstawie planu ortogonalnego, a optymalne parametry napawania np.: natężenie, napięcie, prędkość podawania drutu zostały wyznaczone metodą regresji wielokrotnej oraz metodą Taguchi. Ustalono, że największy wpływ na wartość współczynnika wtopienia ma natężenie prądu głównego łuku plazmowego. Największą wartość współczynnika S/N uzyskano przy parametrach: I = 120 A, U = 31 V, vn = 0,75 m/min, vd = 3,9 m/min, z = 12 mm.

6

Digital image stabilization for the experimental verification of object motion trajectories

Piątkowski Tomasz

Journal of Automation, Electronics and Electrical Engineering

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2022

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Vol. 4, No. 2

23--30

EN

The article presents digital stabilization procedure of the image recorded with a camera performing unintentional spatial movement in relation to the scene. This method consists in carrying out translational and rotational transformations and scaling all frames in relation to the first frame, using the tools of the Matlab environment. The image stabilization procedure allows to effectively improve the image to make it suitable for the analysis of the tracked objects trajectories on the scene, observed from the camera located on the rotor drone.

PL

W artykule przedstawiono procedurę cyfrowej stabilizacji obrazu zarejestrowanego kamerą wykonującą niezamierzony ruch przestrzenny względem sceny. Metoda ta polega na przeprowadzeniu transformacji translacyjnej, obrotowej i skalowaniu wszystkich kadrów względem kadru pierwszego, wykorzystując narzędzia środowiska Matlab. Procedura stabilizacji obrazu pozwala skutecznie uzdatnić obraz, by nadawał się on do analizy torów ruchu śledzonych obiektów na scenie, obserwowanej z kamery umieszczonej na dronie wirnikowym.

7

The Use of GFRP Tubes as Load-Bearing Jackets in Concrete-Composite Columns

Abramski Marcin, Chmielnicki Błażej

Civil and Environmental Engineering Reports

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2022

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Vol. 32, no. 2

96--117

EN

The paper presents the fields of applications of polymer composites in building structures. The use of composite glass fibre tubes is discussed in more detail. The laboratory methods used to test the mechanical properties of these pipes are presented. An original research program is presented, including six concrete-filled glass fibre tubes. The cylinders and columns made in this way were tested for their axial load capacity. Conclusions were formulated regarding the relationship between the load-bearing capacity of the test elements and their length, as well as the angle of glass fibres arrangement in the tube composite.

8

Science curiosities cabinet and the chemical showcase

Szydło Zbigniew A.

Chemistry-Didactics-Ecology-Metrology

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2022

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R. 27, NR 1-2

79--103

EN

With the drastic reduction of the school chemistry teaching program in England in 1986, large quantities of apparatus and chemicals became redundant. The disused apparatus at Highgate School inspired the construction of a chemical showcase for pupils; this has encouraged pupils to develop a passion for chemistry. The idea of a “miniature museum” came from a visit to a local primary school in London, which had a beautiful science curiosities cabinet in one of its rooms. In both schools, sciences thrive, and are popular among pupils. Undoubtedly a display of assorted artefacts, which can be readily accessed by pupils, makes a significant impact on developing their interest in science. It is hoped that the story of these ventures will inspire teachers to make their own versions of these excellent and easily constructed educational facilities.

9

Study on Reclamation of CO2-hardened Sodium Silicate Used Sands by CaO Powder

Lu Jijun, Yang Lei, Qian Jiangbing, He Wei, Wang Huafang

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 3

99--106

EN

Aiming at the problems of wet reclamation consuming a lot of water, dry (mechanical) reclamation having wear and power consumption, this paper to find suitable reclamation reagents to reduce the influence of harmful substances in used sodium silicate sands. By comparing the reclamation effect of CaO, Ca(OH)2 and Ba(OH)2 reclamation powder reagents, it was concluded that CaO had the best reclamation effect. Through the single factor experiment, the influence of CaO on the reclamation effect was explored: 1. addition amount of CaO; 2. the additional amount of water; 3. reclamation time. The orthogonal results showed that the CaO reclamation effect was the best when the amount of CaO was 1.5%, the amount of sodium silicate was 4.0%, the amount of water added was 6.0%, and the reclamation time was 12.0h. In this experiment, 82.2% carbonate and 75.0 % silicate in used sands can be removed. The microscopic analysis of the reclamation sands was carried out by scanning electron microscope (SEM); The surface was relatively smooth, without large area cracks and powder accumulation. Compared with the used sands, the instant, 24h ultimate, and residual strengths of the reclaimed sands were increased by 536.5%, 458.1%, and 89.8%, respectively, which was beneficial to the reclamation of the CO2 sodium silicate used sands.

10

Numerical and experimental study on forming preforms in a CNC skew rolling mill

Pater Zbigniew, Tomczak Janusz, Bulzak Tomasz, Walczuk-Gągała Patrycja

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 1

art. no. e54, 2022

EN

This paper relates to a study on the formation of elongated preforms in a CNC skew rolling mill. First, a numerical analysis was performed to investigate forming processes for three different parts: a scraper, a connecting rod, and a hook. The shapes and dimensions of preforms were designed, and rolling and closed-died forging processes for producing these parts were simulated numerically. Distributions of temperature, effective strain and damage function were determined for rolled preforms. Loads and torques in the rolling process were measured. It was found that the forming process of preforms performed in a CNC skew rolling mill was characterized by relatively low force parameters in relation to the dimensions of formed parts. Numerical simulations of the forging process showed that all forged parts had the required shape, which indicates that the preforms were designed correctly. Following the numerical analysis, experiments were performed in which the preforms were rolled under laboratory conditions (in a scale of 1:2). Experimental results demonstrated that the rolled parts had no internal defects (cracks) and were characterized by high dimensional accuracy.

11

Le domaine de la Terre - the domain of the Earth

Marmur Michał

Zeszyty Naukowe Politechniki Poznańskiej. Architektura, Urbanistyka, Architektura Wnętrz

|

2021

|

Z. 7

135--148

EN

On November 25, 1985 in Villefontaine, the Domaine de la Terre, a unique res idential area in the world was officially opened. About 600 people moved into 65 social flats, housed in twelve apartment islands designed by 10 teams of architects to experiment with various earth-building techniques. The idea of a earth settlement was born in 1980 in Paris. The aim of the experiment was an international exhibition devoted to the history, current events and the future of clay architecture and other local materials. The project has become a testing ground and a place to put new technical solutions into practice.

PL

25 listopada 1985 roku w miejscowości Villefontaine nastąpiło uroczyste otwarcie wyjątkowej na skalę światową dzielnicy mieszkaniowej we Francji: Domaine de la Terre. Około 600 osób wprowadziło się do 65 mieszkań socjalnych umieszczonych w dwunastu wyspach mieszkalnych zaprojektowanych przez 10 zespołów architektów w celu eksperymentowania z różnymi technikami budownictwa ziemnego. Pomysł osiedla z ziemi narodził się w 1980 roku w Paryżu. Celem eksperymentu była międzynarodowa wystawa poświęcona historii, bieżącym wydarzeniom i przyszłości architektury z gliny i innych materiałów lokalnych. Projekt stał się poligonem doświadczeń oraz miejscem do stosowania w praktyce nowych rozwiązań technicznych.

12

Brasília: Ilha da Fantasia. Krótki szkic o mieście

Malinowska-Petelenz Beata

Środowisko Mieszkaniowe

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2021

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nr 37

26--36

PL

Brasília, fantastyczna wyspa - to jedno z najbardziej niezwykłych miast na świecie, które zostały zaprojektowane od początku i w miejscu starannie wybranym do tego celu. Stolica największego kraju Ameryki Południowej, przestrzeń „oswojona”, która nie istniała jeszcze na początku XX wieku, stanowi kwintesencję myśli modernistycznej przeniesionej na grunt latynoamerykański. Utopijna Brasília miała być miastem marzeń, zdekolonizowaną potęgą, realizacją socjalistycznej ideologii, opus magnum Kubitschka i Costy. Bez slumsów i kolonialnej, historyzującej zabudowy. I choć powstała w latach 60. ubiegłego wieku, nadal budzi skrajne emocje. Jak dziś rozwija się owo urbanistyczne arcydzieło i symbol brazylijskiego modernizmu? Co zostało z wyobrażeń i założeń funkcjonalistów?

EN

Brasília, a fantastic island - one of the world’s most extraordinary cities, designed from the ground up at a site carefully preselected for that specific purpose. The capital of South America’s largest country, a “domesticated” space, which did not exist at the start of the twentieth century, it is a quintessence of Modernist thought transplanted into Latin American soil. The utopian Brasília was to be a city of dreams, a decolonized power, the realization of socialist ideology, an opus magnum for Kubitschek and Costa. Without slums and colonial, historicizing development. And although it was built in the 1960s, it still stirs extreme emotions. How does this urban masterwork and symbol of Brazilian Modernism develop today? What has been left of the expectations and assumptions of the Functionalists?

13

Teaching scientific method to primary school pupils by using the example of adaptation of secondarily aquatic animals to the marine environment

Antczak Mateusz

Geologos

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2021

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Vol. 27, No. 3

181--188

EN

Science classes in public schools are usually strictly linked to several subjects and taught by reference to the reading-listening model. Non-formal educational institutions and events such as ‘children universities’ and science fairs (and to some degree also some private schools) implement elements of interdisciplinary teaching of science and learning through experiments and the use of scientific methods. Workshops conducted within non-formal educational structures prove that only is this method engaging and understandable to primary school pupils, it also is possibly much more effective than the traditional learning style for coding information and explaining common misconceptions in teaching evolution, palaeontology and biodiversity. The example of a scenario for science classes presented here (the so-called ‘aquatic problem’, i.e., adaptations of primarily terrestrial animals – amniotes – to the aquatic environment) uses simple props, such as everyday items, to address the problems that teachers in public school face. Thus, it can be implemented independently of school budgets and availability of school equipment.

14

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

|

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.

15

Design and technological capabilities of a CNC skew rolling mill

Tomczak Janusz, Pater Zbigniew, Bulzak Tomasz, Lis Konrad, Kusiak Tomasz, Sumorek Andrzej, Buczaj Marcin

Archives of Civil and Mechanical Engineering

|

2021

|

Vol. 21, no. 2

524--540

EN

Results of a study investigating a skew rolling process for elongated axisymmetric parts are presented. Despite the fact that the skew rolling technique for producing such parts was developed and implemented in the mid-twentieth century, there are no studies on this problem. The first part of this paper presents the results of FEM modelling of skew rolling stepped axles and shafts (solid and hollow). The FEM analysis was performed using the MSC Simufact Forming software. The numerical simulation involved the determination of metal flow patterns, the analysis of thermal parameters of the material during rolling, and the prediction of cracking by the Cockcroft-Latham ductile fracture criterion. Force parameters of rolling solid and hollow parts were also determined. The aim of the FEM analysis was to determine initial design assumptions and parameters for the development of the skew rolling mill. Later on in the paper, a design solution of a CNC skew rolling mill for rolling parts based on their envelope profile is proposed. FEM strength test results of a mill stand, obtained with MSC. NASTRAN, are presented. Finally, the performance test results of the constructed rolling mill are presented. The experiments involved rolling real stepped shafts that were modelled numerically. Obtained results show that the proposed skew rolling method has considerable potential. The designed and constructed rolling mill can be used to perform the rolling process according to the proposed method, with the tool and material kinematics being controlled based on the set parameters of a workpiece envelope.

16

Investigations on pool boiling of refrigerant R141b outside a horizontal tube

Baki Touhami, Aris Abdelkader, Tebbal Mohamed

Archive of Mechanical Engineering

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2021

|

LXVIII, nr 1

77--92

EN

Boiling produces vapor with a phase change by absorbing a consistent amount of heat. Experimentation and modeling can help us better understand this phenomenon. The present study is focused on the heat transfer during the nucleate pool boiling of refrigerant R141b on the surface of a horizontal copper tube. The results of the experiment were compared with four correlations drawn from the literature, and the critical heat flux was examined for different pressures and also compared with the predicted values. Simulating boiling with two-phase models allowed us to infer the plot of the temperature distribution around the tube and compared it to results from other work.

17

Limit states of steel supporting structure for bridge cranes

Mantič Martin, Kuľka Jozef, Kopas Melichar, Faltinová Eva, Hrabovský Leopold

Zeszyty Naukowe. Transport / Politechnika Śląska

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2020

|

z. 108

141--158

EN

This paper describes a question of evaluation necessity of bridge cranes using the method of limit deformation state and oscillation damping. The solution was performed by means of theoretical analysis and an experimental verification at the selected bridge crane. The final result sounds that in the case of a correct strength computing of given bridge crane, it is not necessary to also check deformation and damping of oscillation as well.

18

EKSPERYMENT : weryfikacja czynników produktywności

Rokicki Wojciech

Logistyka

|

2020

|

nr 2

40--42

PL

Celem artykułu jest rzucenie światła na zmienne, na które warto zwracać uwagę przy projektowaniu procesów. Zastosowano podejście doświadczalne - przeprowadzono eksperyment, polegający na symulacji typowego procesu kompletacji i odkładania, obecnego w wielu operacjach produkcyjnych i magazynowych. Badanie sprawdzało zależności między różnymi zmiennymi a wydajnością. Wnioski liczbowe zostały następnie „przekute” w praktyczne rekomendacje biznesowe.

19

Hydrogen - some historical highlights

Szydło Zbigniew A.

Chemistry-Didactics-Ecology-Metrology

|

2020

|

R. 25, NR 1-2

5--34

EN

The early history of experiments in which an inflammable air was prepared is outlined. Once hydrogen had been discovered by Cavendish in 1766, the world of science and technology was given a colossal impetus. Its scientific and social consequences form the main focus of this essay. Special attention is given to explain why experiments were done, and their aims. The many difficulties which confronted scientists in the interpretation of their results are discussed. Timelines have been used in order to facilitate an understanding of the evolution of ideas. A particular emphasis is given to the story of how, through spectral analysis of the hydrogen atom, our understanding of atomic structure developed. Experiments involving hydrogen constitute important teaching material in schools. Detailed instructions are given for making hydrogen in the laboratory and for demonstrating its lightness and flammability. Suggestions are made of how to use these reactions to teach a wide variety of chemical concepts and facts.

20

Eksperymenty budownictwa i architektury. Ku metodzie naukowej w sztuce budowania

Słyk Jan

Builder

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2020

|

R.24, nr 8

9--13

PL

Architektura i budownictwo długo pozostawały poza obszarem ścisłej, naukowej analizy. Teoria dyscypliny rozwijała się przede wszystkim w obszarze historii oraz krytyki. Metodykę projektowania kształtowano na bazie praktycznych doświadczeń: obserwacji, śledzenia procesów użytkowych, sukcesów konstrukcyjnych i katastrof. Ewolucja technik architektonicznych wiąże się ściśle z rozwojem konstruowanych modeli. Dzięki nim sztuka kształtowania przestrzeni zyskała szansę prowadzenia badań empirycznych. Początkowo modele odzwierciedlały wąski wycinek rzeczywistości, głównie jej formę geometryczną. Wraz z rozwojem nauk przyrodniczych stawały się w coraz większym stopniu reprezentatywne. W artykule przedstawiono główne etapy rozwoju modeli architektoniczno-budowlanych. Na tym tle zarysowano zmiany w metodyce prowadzące ku coraz ściślejszym formom rozumowania. Dokładnie przeanalizowano znaczenie cyfryzacji warsztatu dla poprawy jakości modeli. Ten ostatni etap ewolucji zinterpretowano w świetle funkcji cyfrowego medium, nowego elastycznego nośnika informacji o budynku.

EN

Architecture and civil engineering have long remained outside the scope of strict, scientific analysis. The theory of discipline developed primarily in the area of history and criticism. The design methodology was established on the base of practical experience: observation, tracking processes of use, construction successes and disasters. The evolution of architectural techniques is closely related to the development of constructed models. Thanks to them, the art of shaping space gained a chance to conduct empirical research. Initially, models reflected a narrow scope of reality, mainly its geometric form. With the development of natural sciences, models became increasingly representative. The paper presents the timeline of development of architectural and engineering models. On that ground, changes in methodology have been outlined, leading to strict forms of reasoning. The significance of workshop digitization for improving the quality of models was thoroughly analyzed. This last stage of evolution has been interpreted considering the function of the digital medium, a new flexible form of information about the building.