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Influence of the artificial defect on the flexible pipeline twist angle

Nazarenko S., Kovalenko R., Kolienov O., Savelie D., Miachyn V., Demianyshyn V.

Archives of Materials Science and Engineering

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2022

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Vol. 114, nr 2

58--68

EN

Purpose: To establish the dependence of the change in the values of the twisting angle of the flexible pipeline on the internal water pressure and the defect length, which is directed along and across the axis of the sleeve. Design/methodology/approach: Experimental studies were conducted in two stages. At the first stage, the methodology and plan of the experiment were developed, the factors and their values were determined, and experimental studies were conducted. The limits of variation in the area of factor spaces were established based on the basic analysis of a priori information. The length of the defect was 0, 50 and 100 mm. The pressure values in the sleeve were 0.2, 0.4 and 0.6 MPa. Adequacy of the obtained regression equations was checked using Fisher's test. At the second stage, the analysis of the research results was carried out and the numerical values of the factors that most affect the change in the value of the twisting angle of the sleeve were established. Findings: According to the results of experimental studies, the dependences of the change in the twisting angle of the flexible pipeline on the internal water pressure and the length of the defect were obtained. It was established that the dependence of the previously mentioned factors is close to linear. The largest discrepancy in the maximum sleeve twist angle – 21% was observed at pressure values of 0.4 MPa. Research limitations/implications: The research was limited to only two factors: the defect length and the pressure in the middle of the sleeve. Such factors as the degree of wear of the sleeve, the type of sleeve and the number of defects on the test sample were not taken into account. Practical implications: The obtained results can be used during the development of a new method of testing flexible pipelines, which will allow to establish hidden defects in them. Originality/value: For the first time, the dependence of the influence of the size and direction of the defect on the reinforcing frame of the pressure fire hose on the value of its twist angle at constant internal pressure indicators was established.

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Main objectives underlying mathematical model of powered support unit operation in terms of its working capacity

Herezy Ł., Korzeniowski W., Skrzypkowski K.

Mining – Informatics, Automation and Electrical Engineering

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2017

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R. 55, nr 4

72--83 [tekst ang.] 84--95 [tskst pol]

EN

This study synthesizes the operating data of a longwall system to determine the impacts of time, compressive strength of roof rock strata, rate of face advance, and distance between the cross bar in a roof support from the side wall on the value of the actual working capacity of powered supports. The analyses of the general linear models are supported by the Statistica program. Criteria imposed on the input data lead to the development of models of the powered support unit (shield) operation yielding corrected value of the coefficient R2(0,11-0,42), rendering the models statistically significant. For the investigated longwall panel, the minimal bearing capacity of the powered support obtained by several methods is compared with the actual bearing capacity of the powered support units. Mathematical models were recalled to obtain the pressure value that can be used in the further procedure as: – pressure in a shield leg required to obtain the load-bearing capacity of a hydraulic leg in response to the load applied to the powered support, – pressure exerted by rock strata on the longwall excavation, which is utilized to determine the real load acting on the powered support unit. In the context of these two objectives, the roof stability factor was obtained accordingly, revealing excellent support-strata interactions under the specified geological and mining conditions.

PL

W artykule posłużono się zgromadzonymi danymi dotyczącymi pracy kompleksu ścianowego, aby wyznaczyć wpływ czasu, wytrzymałości skał stropowych na ściskanie, postępu ściany, odległości stropnicy sekcji od ociosu na wartość osiąganej podporności roboczej. W tym celu w programie Statistica wykonano analizy z wykorzystaniem ogólnych modeli liniowych. Przyjęte kryteria danych wejściowych pozwoliły na uzyskanie modeli pracy sekcji o skorygowanym R2 wynoszącym 0,11–0,42, kwalifikującym te modele jako istotne statystycznie. Dla rozpatrywanego pola ścianowego określono wymaganą minimalną podporność roboczą sekcji dla kilku sposobów jej wyznaczania i porównano z podpornością zastosowanych sekcji obudowy. Następnie na podstawie modeli matematycznych wyznaczono wartość ciśnienia roboczego, które można wykorzystać jako: – ciśnienie w stojaku hydraulicznym i na jego podstawie obliczyć podporność stojaka hydraulicznego będącą reakcją na obciążenie sekcji, – ciśnienie wywierane przez górotwór na wyrobisko eksploatacyjne, z którego można wyznaczyć rzeczywiste obciążenie sekcji obudowy zmechanizowanej. Dla obydwu założeń wyznaczono wskaźnik nośności stropu. Jego wartości świadczą o bardzo dobrej współpracy sekcji z górotworem w rozpatrywanych warunkach geologiczno-górniczych.

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Wpływ zależności kształtowo-wymiarowych i ciśnienia roboczego na grubość ścianki zbiorników ciśnieniowych projektowanych według WUDT/UC/2003

Piwowarczyk T., Nabielec T.

Przegląd Spawalnictwa

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2015

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R. 87, nr 8

39--46

PL

W pracy dokonano analizy zmian grubości materiałów stosowanych do wytwarzania zbiorników ciśnieniowych w zależności od ich kształtu i wymiarów oraz ciśnienia roboczego. Obliczeń dokonano na podstawie formuły przygotowanej na bazie wytycznych WUDT/UC/2003. Zaprezentowano wpływ długości, średnicy, ciśnienia oraz zmiany wymiarów zbiornika na grubość ścianki. Porównano różne rozwiązania konstrukcyjne dennic oraz określono wpływ geometrii dna wypukłego na grubość jego ścianki. Podano wytyczne kontroli stateczności projektowanego zbiornika poziomego.

EN

In this paper analysis of changes in thickness of materials used in manufacture of pressure vessels based on their shape, size and applied pressure are made. Calculations were made on the basis of prepared analytical formula according to guidelines WUDT/UC/2003. Influence of length, diameter, pressure and changes in dimensions of wall thickness of tank are presented. Different heads designs are compered and influence of dished head geometry on wall thickness are determined. Guidance of stability control of designed horizontal pressure vessel are provided.

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A parametric study on the mechanical performance of buried X65 steel pipelines under subsurface detonation

Mokhtari M., Alavi Nia A.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 3

668--679

EN

Existing studies on the response of buried steel pipelines to explosion generally concern finding safe distance of explosion where pipeline does not undergo plastic deformation while intentional explosions impose intense deformations on steel pipelines. In order to address this gap, the present investigation is carried out numerically dealing with the response of buried API 5L grade X65 pipelines to a nearby sever explosion due to sabotage or war. Furthermore, the effects of the pipeline diameter-to-thickness ratio and internal pressure on this response were investigated numerically. A combined Eulerian–Lagrangian (CEL) method was adopted to develop a full-coupled 3D finite element model. Employing simplified Johnson-Cook material model to simulate mechanical behavior of steel pipelines and considering air in the model increased the simulation accuracy. The results from present study were compared with those of recent investigations and good agreements were observed. The results show that, the amount of deformation and consequently the value of maximum equivalent strain of pipelines decrease with either increase in operating pressure or decrease in diameter-to-thickness ratio; however, the effect of pipeline internal pressure was far more than diameter-to-thickness ratio. The results obtained from the present study can be used for improvement in protective design of steel pipelines.

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The effect of pressure on heat transfer during pool boiling of water-A1[2]0[3] and water-Cu nanofluids on stainless steel smooth tube

Cieślinski J.T., Kaczmarczyk T.Z.

Chemical and Process Engineering

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2011

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Vol. 32, nr 4

321-332

EN

Experimental investigation of heat transfer during pool boiling of two nanofluids, i.e. water-Al203 and water-Cu has been carried out. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. The horizontal smooth stainless steel tubes having 10 mm OD and 0.6 mm wall thickness formed the test heater. The experiments have been performed to establish the influence of nanofluids concentration on heat transfer characteristics during boiling at different absolute operating pressure values, i.e. 200 kPa, ca. 100 kPa (atmospheric pressure) and 10 kPa. It was established that independent of nanoparticle materials (A1203 and Cu) and their concentration, an increase of operating pressure enhances heat transfer. Generally, independent of operating pressure, sub- and atmospheric pressure, and overpressure, an increase of nanoparticle concentration caused heat transfer augmentation.