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The Influence of Printing Parameters on Leakage and Strength of Fused Deposition Modelling 3D Printed Parts

Szczęch Marcin, Sikora Wojciech

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

195--201

EN

Fused Deposition Modelling (FDM) 3D printing technology has become popular for producing prototypes and final parts in various industries, including the automotive, aerospace, and medical sectors. The leakage of such components is often an important factor in determining their possible applications. This paper focuses on researching the influence of printing parameters on leakage and relating the results to the strength of parts produced using this technology. The printing parameters considered were temperature and layer height. PLA (polylactic acid) was chosen as the material due to its biodegradability and biocompatibility. Leakage measurements were carried out using an empty cylinder-shaped vessel filled with air under pressure. The leakage value was observed as a pressure drop over time. It was shown that 3D-printed FDM vessels are not perfectly leak-proof, but the value of observed leakage may be acceptable for selected applications (leakage below 2.5 Pa/s). The results showed a high correlation be-tween the height of the printed layer in both the leakage and strength of the tested samples, while reducing the height increased the tightness and strength of the 3D-printed parts. The effect of printing temperature was less significant.

2

Conception of a Durability Prediction Method for a Metal-elastomer Machine Mount

Sikora Wojciech, Pilch Robert, Smolnik Maksymilian

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 5

28--40

EN

Elastic elements utilised in the support systems of machines are subjects to deterioration processes dependent on the character of their operational loads, work environment and construction. The extent of this change and work time after which it occurs is important information in the maintenance process, necessary for its planning. This paper presents the developed concept of durability prediction method of a four-joint metal-elastomer machine support based on the variation of working temperature of its elastomer elements. Therefore, the solution enables the estimation of significant indexes determining the life cycle of the mount. The developed simulation model is a useful tool for designers, allowing them to estimate the time of the machine mount’s correct work. It also helps the operator to schedule the inspections of technical condition (degree of wear) of the machine mount and prepare its replacement operations accordingly. This problem is significant because any failure to an element usually generates higher costs than carrying out a scheduled preventive replacement.

3

Experimental investigation of a uniaxial dielectric elastomer generator

Sikora Wojciech

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 4

499--506

EN

The widespread use of battery-powered electronic devices creates the need to develop methods to extend their maximum operating time. This can be achieved by using ambient energy, which would otherwise be dissipated. The conversion of energy, usually mechanical energy, into electric energy takes place in energy harvesters. Energy harvester systems based on a dielectric elastomer (DE) are a relatively new field that is being constantly developed. Due to their features, dielectric elastomer generators (DEGs) may complement the currently dominant piezoelectric harvesters. The major feature of employing a hyperelastic material is that it allows relatively large displacements to be utilised for generating energy, which is impossible in the case of piezoceramics. This article presents a DEG designed to operate under uniaxial tensile loads and which has a multilayer structure, describes the general operating principles of a DEG, explains the construction and assembly process of the investigated design and shows the electric circuit necessary to properly direct current flow during the DEG operation. The experimental part consists of two series of tests based on a central composite design (CCD). The objective of the first part was to map a capacitance response surface of the DEG in the selected range of the cyclic mechanical load. The second part concerned the amount of generated energy for the specific load case as a function of operating voltages. The result of the work is the formulation of regression models that allow the characteristics of the presented DEG design to be identified.

4

Physical and reliability aspects of high-pressure ammonia water pipeline failures

Michnej Maciej, Młynarski Stanisław, Pilch Robert, Sikora Wojciech, Smolnik Maksymilian, Drożyner Przemysław

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 4

728--737

EN

The paper concerns the problem of the occurrence of failures of the high-pressure ammonia water pipeline of the coke oven battery complex, which is affected by chemical and thermal factors as well as the operating pressure occurring during its use. Pipeline failures manifested themselves as leaks (leakage of the medium) due to cracks in the area of the pipeline thermal elongation compensators. The conducted tests included, among others: visual inspection, penetration tests, macroscopic and microscopic tests as well as chemical analysis of the material. The study includes microscopic photographs of the material structure and cracks. The results of the pipeline strength and reliability analysis were also presented. On the basis of the conducted research and analyses conclusions were formulated. The assumed cause of the damage was the incorrectly made welded joints. Formulated recommendations and proposals for actions aimed at avoiding further failures of this and similar pipelines were related to the inspection time and preventive renewal.

5

Equivalent parameters of metal-elastomer vibroinsulators

Cieplok Grzegorz, Wójcik Kaja, Michalczyk Krzysztof, Sikora Wojciech

Vibrations in Physical Systems

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2020

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Vol. 31, nr 2

art. no. 2020204

EN

This paper concerns a substitute model of the metal-elastomer vibroinsulator that can find use in the mathematical description of vibration machine suspensions. In the case of a plane system, the flexibility matrix of the vibroinsulator was derived and two typical configurations of machine suspensions: symmetrical and asymmetrical, were analysed. For the case of a spatial motion, the elastic matrix of the vibroinsulator and the method of determining its elements was specified. Due to the non-linear character of the vibroinsulator's work, which is caused by large deformations of elastomeric elements under static loads, the analysis was limited to the surroundings of the work point and linear model. The results of theoretical analyses were confirmed by experimental tests.

6

Prefabrykacja konstrukcji z litego drewna

Sikora Wojciech

Materiały Budowlane

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2020

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nr 11

21--23

7

Mechanical and Tribological Analysis of Monolith and Coating Polyetheretherketone

Otto Mateusz, Zimowski Sławomir, Sikora Wojciech, Moskalewicz Tomasz

Tribologia

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2019

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nr 4

73--86

PL

W pracy dokonano analizy porównawczej właściwości mikromechanicznych oraz tribologicznych polieteroeteroketonu (PEEK) w postaci monolitycznej i powłoki. Powłoka PEEK 708 została osadzona metodą elektroforezy na płaskim podłożu ze stopu tytanu. Właściwości mikromechaniczne zostały zbadane metodą indentacyjną przy użyciu wgłębnika Vickersa oraz w teście zarysowania. Na podstawie badań wyznaczono twardość Vickersa (HV), moduł sprężystości (E), twardość zarysowania (HS) oraz odporność na mikrouszkodzenia (MMR). Właściwości tribologiczne zdefiniowano poprzez współczynnik tarcia (fs i fw), który wyznaczono zarówno w teście zarysowania oraz podczas tarcia w układzie typu kula–tarcza. Wyniki badań wskazują, że pomimo niedużo większej twardości Vickers’a (HV) powłoki PEEK 708 (HV = 350 MPa, HS = 300 MPa) względem monolitycznego PEEK (HV = 300 MPa, HS = 210 MPa), występuje niemal 40% różnica w ich twardościach zarysowania (HS). Z przeprowadzonej analizy wynika, że metody wyznaczania parametrów mikromechanicznych oraz tribologicznych stosowane dla materiałów monolitycznych PEEK sprawdzają się w badaniach powłok polimerowych PEEK. W określonych warunkach badań nie stwierdzono wpływu materiału podłoża na otrzymane wyniki dla powłoki PEEK 708.

EN

In this work, a comparative analysis of the micromechanical and tribological properties of polyetheretherketone (PEEK) in bulk and coating form was performed. The PEEK 708 coating was applied on a Ti6Al4V titanium alloy flat specimen using the electrophoretic deposition method. The micromechanical properties were determined through indentation tests performed using the Vickers method and scratch tests. Based on research work, the Vickers hardness (HV), elastic modulus (E), scratch hardness (HS), and Micro Mar Resistance (MMR) were determined. The tribological properties were defined by the coefficient of friction (fs and fw), which was obtained in scratch tests and ball-on-disk tests. The results of this research indicate, despite the slightly higher Vickers hardness (HV) of the PEEK 708 coating (HV = 350 MPa, HS = 300 MPa) relative to PEEK bulk (HV = 300 MPa, HS = 210 MPa), that there is an almost 40% difference between the scratch hardness (HS) values of these PEEK forms. It appears from the result analysis in this paper that testing methods to determine the micromechanical and tribological properties of PEEK in monolith form can be used for both PEEK coatings. Under certain test conditions, the impact of the substrate properties on the results of the PEEK 708 coating was not found.