Wyniki wyszukiwania - BazTech

1

CFD Simulation of Heat Transfer Through a Window Frame

Basok Borys, Novikov Volodymyr, Pavlenko Anatoliy, Davydenko Borys, Koshlak Hanna, Goncharuk Svitlana, Lysenko Oksana

Rocznik Ochrona Środowiska

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2024

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Tom 26

56--64

EN

The use of various coatings with a low level of radiation on the glass elements of window structures, filling the interglacial space in double-glazed windows with inert gases instead of air, increasing the number of cameras in double-glazed windows, other constructive measures aimed at improving the thermal insulation properties of double-glazed windows, led to a significant increase in the thermal resistance of the fenestration system. However, little has changed in the design and construction of window frames and edge areas adjacent to building facades, leaving these elements responsible for heat transfer through modern windows. In this article, with the help of three-dimensional CFD modeling, the thermal insulation properties of window frames are investigated in the most complete setting, taking into account the effect on heat transfer through the profile of the window frame of the adjacent walls of the building facade on one side and the double-glazed unit on the other. Finding out the thermal insulation parameters of the window frame will help to make appropriate changes in its design.

2

Validation research of pressure decay test method for internal leakage detection of hydraulic cylinder

Li Weijie, Qian Xinbo, Chen Xinyuan, Li Feihong, Lu Yan

Eksploatacja i Niezawodność

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2024

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Vol. 26, no. 2

art. no. 184039

EN

Leakage test is one of the acceptance tests to ensure hydraulic cylinder reliability. Under the consideration of economic and technical maturity conditions, the existing internal leakage detection methods may be difficult to achieve rapid screening. After research, the pressure decay test method is a common method of quickly testing hydraulic cylinders for internal leakage in the manufacturing industry. However, the validity of the pressure decay test method has not been theoretically verified, limiting the versatility of the method. This paper will theoretically validate the effectiveness of the pressure decay test method and provide important theoretical support for its use as a general rapid screening method for internal leakage, thereby improving the reliability and safety of hydraulic systems. Both simulation and experimental results show that there is a linear relationship between the pressure decay rate and the internal leakage rate. Especially for working pressures greater than 16 MPa, the pressure factor has an insignificant impact on the application of this method.

3

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

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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.

4

Numerical Modelling of a Rotary Compression Test on a Cylindrical Specimen

Pater Zbigniew

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 4

23--32

EN

This paper reviews studies on the modelling of the Mannesmann effect, which leads to the formation of an axial crack in parts formed by cross and skew rolling. This effect also occurs in the rotational compression (RC) test of a cylindrical specimen, which is used to determine the critical damage value. RC tests were carried out under laboratory conditions at the Lublin University of Technology on C45 steel specimens formed at 950°C. Based on the tests, the crack propagation was presented as a function of the progress of rotational compression, measured by the length of the deformation path. The RC tests were numerically modelled in Forge® using four ductile fracture criteria. The effectiveness of the Mannesmann effect modelling was evaluated by comparing the numerically predicted cracks with the experimentally determined ones. In addition, the influence of an occurring axial crack on the stress state in the forming specimen was analysed.

5

Forging of a Hollow Ball Using a Deformable Insert Assembly

Samołyk Grzegorz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 5

32--40

EN

The paper presents selected results of numerical analysis and experimental verification. The subject is the analysis of cold forging of a thin-walled hollow ball. The process of making a ball out of aluminum alloy and steel is considered. A distinctive feature of this process is the use of a special deformable insert assembly. It consists of two shaped expanding tubes, a distance ring and a centering tube. Each of these elements has a specific function, which is characterized in this article. FEA simulation allowed proving the functionality of the insert assembly and comparing the cold forging of a steel and aluminum part, using the same inserts. Attention was also focused on the impact of the accuracy of the positioning of the insert assembly. Experimental verification confirmed the correctness of the modeling and complemented the results from FEA analysis.

6

Zależność wartości współczynnika przepływu C od grubości kryzy z wlotem stożkowym

Golijanek-Jędrzejczyk Anna

Przegląd Elektrotechniczny

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2023

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R. 99, nr 11

20--25

PL

W artykule przedstawiono wyniki badań numerycznych i eksperymentalnych pięciu kryz z wlotem stożkowym o współczynniku przewężenia  równym 0,24, o grubości od 2,5 mm do 31 mm (każda ścięta skośnie pod kątem 45°) umieszczonych w wodnej instalacji hydraulicznej przy przepływach laminarnych i turbulentnych. Uzyskane rezultaty potwierdziły, że wraz ze wzrostem grubości (w badanym zakresie liczb Reynoldsa od 1690 do 14430) tego typu kryzy wartość współczynnika C dąży do wartości 0,9.

EN

This paper presents the results of a numerical and experimental study of five conical inlet orifices with a reduction ratio  equal to 0.24, with thicknesses ranging from 2.5 mm to 31 mm (each bevelled at 45°) placed in a hydraulic system with water medium in laminar and developed turbulent flows. The results confirmed that as the thickness increases (in the range of Reynolds numbers studied, from 1690 to 14430) of this type of orifice, the value of the C -factor tends to be 0.9.

7

Preservatives in fruit jams

Żmuda-Czerwonka Wioletta

Polish Technical Review

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2023

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No. 1

18--20

EN

The modern human diet is the subject of research and interest for a large group of specialists. The unlimited capabilities of synthesising new chemical substances and the far-reaching changes in legislation create a space for expanding the list of permissible food additives. Despite the research conducted on new substances, the consumers are afraid that not all additives are sufficiently safe. This is frequently due to lack of access to objective and scientifically-verified information. The most concern is caused by the use of multiple additives in the same food product, which increases the risk of their accumulation in the human body. The objective of this paper is to discuss preservatives added to jams. It involves a discussion of the technological process and indicates the moment that a given preservative is added, showing photographs and findings from an experiment conducted on a single type of jam. The experiment was conducted under domestic conditions.

PL

Dieta współczesnego człowieka to przedmiot badań i zainteresowania dużej grupy specjalistów. Nieograniczone możliwości syntezy nowych substancji chemicznych i daleko idące zmiany w ustawodawstwie dają pole do rozszerzania listy dopuszczalnych dodatków do żywności. Pomimo badań nad nowymi substancjami istnieje obawa konsumencka, że nie wszystkie dodatki do żywności są wystarczająco bezpieczne. Jest to często wynikiem braku obiektywnych i potwierdzonych naukowo informacji. Najwięcej obaw budzi stosowanie wielu dodatków w jednym produkcie spożywczym, a to zwiększa ryzyko ich kumulacji w organizmie człowieka. Założeniem artykułu jest przybliżenie jakie substancje konserwujące pojawiają się w dżemach. Przedstawienie procesu technologicznego i wskazanie momentu kiedy dana substancja konserwująca jest dodawana oraz przedstawienie zdjęć i wniosków z doświadczenia jakiemu poddano jeden rodzaj dżemu. Doświadczenie to wykonano w warunkach domowych.

8

Study on the influence of chamfer perforation on heave and pitch of a single floating platform

Wang Wei, Fan Sheming, You Yunxiang, Zhao Cheng, Xu Liqun, Wang Guibiao, Lu Zhiqiang

Polish Maritime Research

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2023

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nr 1

43--53

EN

The aim of this work is to study the influence of chamfered perforation and chamfering on the heave and pitch motion of a single floating wind power platform with an anti-heave device. Firstly, the hydrodynamic performance of a single floating body with different chamfers, or without perforation, is calculated and analysed. Secondly, the motion of a model without perforation and with 35° chamfered perforation is captured and studied in a towing tank. The results show that when the wave height is large and the period is small, the perforated device has a certain effect. When the wave height and period are small, the pitch suppression effect of chamfered perforation is more obvious than that of non-chamfered perforation. When the period and wave height are large, the heave suppression effect of non-chamfered perforation is better than that of chamfered perforation. In experimental research, the perforated floating body has a certain effect on restraining the heave and pitch of a floating body under most working conditions, and the effect of restraining the pitch is obviously better than that of restraining the heave.

9

Identification of the object motion trajectory in a digital image using the Kalman filter

Piątkowski Tomasz

Journal of Automation, Electronics and Electrical Engineering

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2023

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Vol. 5, No. 3

31--45

EN

The paper concerns identification of the object motion trajectories in a digital image. An image analysis procedure was used consisting of two methods: BLOB identification and Kalman filter. BLOB identification is the superior method, and the Kalman filter is an alternative one, used to determine the motion trajectories only in the event of incorrect BLOB identification. Data from the correct BLOB identification are used on an ongoing basis in the process of training the Kalman filter. In this way, the filter becomes a model of a physical object that allows predicting the future state based on the object's current behaviour. The use of two complementary image analysis methods allows to determine the motion trajectories of the object's characteristic points in conditions of uneven scene lighting. The effectiveness of the method was confirmed in experimental rests.

10

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

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2023

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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.

11

Verification of the Random Nature of the Experimental Data in the End-Milling Process of Aluminum Alloys

Pop Alina Bianca, Țîțu Aurel Mihail

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

967--971

EN

From a theoretical point of view, the research carried out in this manuscript was carried out starting from the study of the links between surface roughness and cutting speed, cutting depth and feed per tooth in the end milling process. From an experimental point of view, it started from the organization and development of the physical cutting process, the cutting regimes to be analyzed were established, after which the surface roughness was determined and measured. In this way, the connections between the factors and parameters pursued in the research resulted. The main purpose of this research is to check the random nature of the measured data related to the quality of the end milled surface of the Al7136 aluminum alloy. The main types of statistical processing performed on the sample values from the experimental measurements, the algorithms and the corresponding work modes are according to the method of research that is based on the use of the Young test. The conclusions highlighted the importance of adopting this research method and opened new directions of study.

12

Multi-Variant Analysis of the Cross Wedge Rolling Process for Producing Railcar Axles

Pater Zbigniew, Tomczak Janusz, Bulzak Tomasz Adam

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 5

208--219

EN

This study investigates the cross wedge rolling (CWR) process for manufacturing a rail axle in a scale of 1:6. Three cases of the rolling process are modelled numerically: standard rolling, wasteless rolling and rolling from a preform. The rolling cases under analysis are compared in terms of material and energy consumption, forming loads as well as propensity to internal and external defect formation. Using the Cockcroft-Latham criterion and the limits of this criterion determined by the rotary compression test, an assessment was made of the propensity of the material to fracture during the rolling processes analysed. Based on numerical results, standard CWR is selected for experimental verification. Obtained experimental results confirm that CWR is an effective method for producing railcar axles that are free from both internal and external defects. The experimental and numerical results obtained confirm that cross wedge rolling technology can be successfully used under industrial conditions for the production of long axles or shafts.

13

Stability investigation of the pcm nanocomposites

Cieśliński Janusz T., Boroń Paulina, Fabrykiewicz Maciej

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 3

381--389

EN

Ensuring the stability is a key issue to be solved for the technical application of nanocomposites. In this work, fatty acid P1801 served as base phase change material (PCM)P1801, and its main ingredients are palmitic acid (58%) and stearic acid (38%). Titania (TiO2) and alumina (Al2O3) with mass concentrations of 1% and 5% were selected as nanoparticles, while polyvinylpyrrolidone (PVP) or oleic acid (OA) with mass concentrations of 5% were tested as surfactants. On the basis of the measured temperature distributions in the sample, which is subject to melting and solidification processes, it was determined which of the tested nanocomposites are stable and which are not. In addition, a thermal test was proposed to assess the stability of the produced nanoPCM, which consists in measuring the temperature distribution versus time according to a precisely given procedure.

14

Krajobraz i jego ocena w ujęciu fenomenologicznym

Bonenberg Wojciech

Zeszyty Naukowe Politechniki Poznańskiej. Architektura, Urbanistyka, Architektura Wnętrz

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2022

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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

15

Model of the city

Słyk Jan

Przestrzeń i Forma

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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.

16

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

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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.

17

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.

18

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

|

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.

19

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.

20

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

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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.