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1

Zjawiska cieplne związane z odkształceniem plastycznym w czasie rozciągania i ich interpretacja na poziomie mikroskopowym

Ostromęcka Małgorzata, Siwiec Jakub

Problemy Kolejnictwa

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2022

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Z. 195

49--56

PL

Zjawiska cieplne dotyczące odkształceń plastycznych mogą być powszechnie obserwowane. Wystarczy dotknąć zerwanej, czy zgiętej próbki, aby przekonać się, że w miejscu odkształcenia wzrosła temperatura. Obserwacje takie mogą być prowadzone w celu oceny jakościowej lub ilościowej. Niniejszy artykuł służy do jakościowego powiązania zmian zachodzących w strukturze odkształcanego materiału ze wzrostem temperatury zaobserwowanym przy użyciu kamery na podczerwień.

2

A comparison of elasto-plastic parameters of S355 steel obtained in tensile tests using an extensometer, a strain gauge and an ARAMIS 3D DIC system

Chybiński Marcin, Dębiński Janusz, Glema Adam, Grzymisławska Justyna, Jezierski Dariusz, Polus Łukasz, Szymkuć Wojciech

Archives of Civil Engineering

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2022

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Vol. 68, nr 4

199--217

EN

The paper presents a comparison of three strain measurement methods. The mechanical parameters of S355 grade steel (yield strength, tensile strength, modulus of elasticity) were determined in tensile tests. Strains were measured using high resolution measuring instruments: an extensometer, a strain gauge and an ARAMIS 3D DIC system. In this paper, these three instruments have been used simultaneously in tensile tests for the first time. The results indicate that the values of the Young’s modulus obtained using different techniques were similar when each instrument measured strain on the same side of the sample. Small differences were connected with different gauge lengths and their locations. The values of the Young’s modulus determined on the opposite sides of the samples were more varied even when the same method was used (strain gauge measurements). For this reason, it is recommended to use double-sided averaging instruments when the Young’s modulus is determined. The strain-curves obtained from the strain gauge measurements were incomplete and they came to an end at the end of the yield plateau due to the fact that they were damaged when the values of strain were relatively high. The extensometer was used up to the point where the strain reached 0.3% and then the strain was measured based on the distance between the machine clamps. The stress-strain curves obtained from the DIC system were complete because the system was able to monitor the sample until the very end of the tests.

PL

W artykule przedstawiono porównanie trzech metod pomiarowych odkształceń. Autorzy wyznaczyli parametry mechaniczne stali S355 (granicę plastyczności, wytrzymałość na rozciąganie, moduł elastyczności) w próbie rozciągania. Odkształcenie zostało wyznaczone przy użyciu przyrządów pomiarowych o wysokiej rozdzielczości: ekstensometru, tensometru oraz systemu cyfrowej korelacji obrazu ARAMIS 3D. Po raz pierwszy w próbie rozciągania wykorzystano wszystkie urządzenia pomiarowe jednocześnie. Wartości modułu Younga wyznaczone za pomocą różnych metod były zbliżone, gdy urządzenie mierzyły odkształcenie po tej samej stronie próbki. Niewielkie różnice wynikały z różnych długości pomiarowych oraz z faktu, że przyrządy nie mierzyły odkształcenia dokładnie na tej samej bazie pomiarowej. Wartości moduły Younga wyznaczone dla przeciwnych stron próbki różniły się bardziej nawet, gdy zastosowano tą samą metodę pomiarową (pomiar odkształceń za pomocą tensometrów). W związku z tym w celu wyznaczenia prawidłowej wartości modułu elastyczności zaleca się stosowanie dwóch urządzeń rozmieszonych na przeciwnych stronach próbki oraz obliczanie modułu sprężystości na podstawie średniej wartości odkształcenia. Krzywe naprężenie-odkształcenie otrzymane z pomiarów tensometrycznych były niekompletne i kończyły się zaraz po półce plastycznej, ponieważ tensometry ulegały uszkodzeniu przy większych wartościach odkształceń. Ekstensometr był wykorzystywany do momentu, w którym odkształcenia osiągnęły wartość 0,3%. Od tej wartości odkształcenia były wyznaczane na podstawie odległości między szczękami maszyny. Krzywe naprężenie-odkształcenie otrzymane na podstawie cyfrowej korelacji obrazu były kompletne, ponieważ system mógł obserwować próbkę przez całe badanie. Z tego względu, metoda cyfrowej korelacji obrazu jest skutecznym narzędziem, które może być wykorzystane do wyznaczania parametrów mechanicznych stali.

3

Young’s modulus of a carbon-reinforced composite at an elevated temperature

Szczepaniak Robert, Przybyłek Paweł, Komorek Andrzej, Sapiński Przemysław, Rowicki Artur, Tkaczuk Sławomir, Rypulak Andrzej, Stabryn Sebastian

Technologia i Automatyzacja Montażu

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2021

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nr 4

29--33

PL

Konstrukcje lotnicze są eksploatowane w zmiennych warunkach środowiskowych wpływających na właściwości kompozytów polimerowych, z jakich często wykonywane są elementy samolotów i śmigłowców. Jednym z takich czynników jest temperatura użytkowania, zmieniająca się podczas lotu w bardzo szerokim zakresie. W artykule zaprezentowano wpływ temperatury eksploatacji na właściwości kompozytu wyznaczane podczas próby rozciągania. Dodatkowo kompozyty przeznaczone do badań wygrzewano w trakcie przygotowania w różnych temperaturach (zgodnie z zaleceniami producenta żywicy będącej osnową). Kompozyty składały się z 7 warstw tkaniny węglowej przesyconych żywicą epoksydową L285 z utwardzaczem. W wyniku badań zauważono, że zmiana temperatury eksploatacji wywiera istotny wpływ na właściwości wytrzymałościowe kompozytu bez względu na temperaturę wygrzewania. Materiały wygrzewane w wyższych temperaturach cechowała większa wartość współczynnika sprężystości wzdłużnej i wytrzymałości na rozciąganie.

EN

Aviation structures are operated under varying environmental conditions, affecting the properties of polymer composites, which are often used to manufacture components for airplanes and helicopters. One of such factors is an operating temperature that changes during a flight in a very wide range. This paper presents the influence of an operating temperature upon composite properties determined during a tensile test. In addition, composites which are intended for the research were post cured during their preparation at different temperatures (in accordance with the recommendations of the resin manufacturer which constitutes a matrix base). The composites consisted of 7 layers of carbon fabric, and matrix of L285 epoxy resin, with a hardener. As a result of the testing it was noted that a change in the operating temperature exerts a significant effect on composite strength properties regardless of the post curing temperature. The materials post cured at higher temperatures were characterized by a greater value of the modulus of elasticity and tensile strength.

4

Distribution of microhardness in polypropylene/talc microcomposite

Bechikhi Youcef, Bouiadjra Bachir Bachir, Bouziane Mohamed Mokhtar, Bouiadjra Bel Abbes Bachir, Benbarek Smail

Composites Theory and Practice

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2021

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R. 21, nr 4

141--148

EN

In this study the distribution of microhardness in a polypropylene microcomposite reinforced with talc microparticles was measured experimentally. The microhardness was measured at different points of the composite material to try to observe the effects of the talc particles and their proportion in the composite on the hardness of the reinforced polymer. Four proportions of talc were used: 5,40 and 50 wt.%, in addition to virgin polypropylene, which was taken as the reference. Statistical analysis was performed on the distribution of the microhardness in the PP+talc composites to determine the average microhardness and the standard deviation. The obtained results reveal a random distribution of the microhardness of the composite, but in general the presence of talc particles increases the microhardness of the polypropylene.

5

A new method for measurement the residual stresses in friction stir welding

Jweeg M.J., Hamdan Z.Kh., Majeed A.H., Resan K.K., Al-Waily M.

Archives of Materials Science and Engineering

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2021

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Vol. 112, nr 2

63--69

EN

Purpose: The residual stresses in different welding methods are fundemental problems to consider. Friction stir welding is one of a solid state joining process, it is economical in that it permits joining together different materials, the specimens in this method (FSW) have excellent properties of mechanical as proven by tensile, flextural and fatigue tests, also it is environmentally friendly process minimizes consumption of energy and generate no gasses or smoke. In friction stir welding , there are two kinds of generated residual stresses: tensile stress and compressive stress. So, this study measuring the residual stresses by using a new method for measuring residual stresses depends on tensile testing and stress concentration factor, this method is a simple, fast and low cost, also it is not need special device. Design/methodology/approach: In previous studies, several techniques were used to predict the value of residual stress and its location, such as destructive, semi-destructive, and non-destructive methods. In this study, a simple, new, and inexpensive way was used based on the tensile test and stress concentration of the friction stir welding (FSW). Findings: By comparing the results obtained with the previous studies using the X-ray method, with the current research, it was found that the results are good in detecting the location and value of the residual stress of friction stir welding. The value of discrepancy of the residual stress in the results between those obtained by the previous method and the current method was about 3 MPa. Research limitations/implications: There are many rotational and linear feeding speeds used in this type of welding. This research used two plates from 6061 AA with 3mm thickness, 100 mm width, and 200 mm length. The rotational speed used in friction stir welding was 1400 rpm, and the feeding speed was 40 mm/min. Practical implications: The residual stress obtained with the new method is 6.2 MPa, and this result approximates other known methods such as the X-ray method in previus studies. Originality/value: Using a new simple method for measuring residual stresses of friction stir welding depends on stress concentration factor and tensile testing. This method is fast and low cost , also it is not need specialized device, compared to other methods such as x-ray or hole drilling methods.

6

Preliminary Investigations of Structure and Properties of TIG Welded Ti-6Al-4V Alloy

Dewangan Saurabh, Ranjan Raushan, Chattopadhyaya Somnath, Gope Deepak, Bogdan-Chudy Marta

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 1

156--165

EN

The titanium (Ti) and its alloys are taken into interest for commercial purpose due to its low density, high yield strength and high corrosion resistance properties. The present work deals with microstructural observation and mechanical property analysis of tungsten inert gas (TIG) welded Ti-6Al-4V alloy joints. For the purpose, two different set of plates were welded at same current and voltage, i.e., 190 A and 24 V, by the TIG welding technique. A critical analysis of the microstructure and mechanical properties like tensile strength and hardness of the welded Ti-6Al-4V plates was carried out in this work. It was found that both plates showed different behavior during the tension test. Plate 1 had 464.54 MPa of tensile stress and it broke at the welded joint. Plate 2 was unaffected at the welded zone but was broken at the base metal zone. The second plate had tensile strength of 501.83 MPa. According to the hardness test, both the welded plates possessed the highest hardness at the welded zone. However, plate 2 showed approximately 10% higher hardness than that of plate 2. A proper inter-relationship was observed between the mechanical behavior and microstructural appearance. The microscopic view of the welded joints revealed the presence of α, β and martensitic-α phases.

7

Joining the High-Strength Steel Sheets Used in Car Body Production

Kaščák Ľuboš, Cmorej Denis, Spišák Emil, Slota Ján

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 1

184--196

EN

Nowadays, there are several important reasons for using high-strength sheets in the manufacturing of car bodies. Car manufacturers choose the steel with good formability, fatigue resistance and ability to absorb impact energy. Microalloyed steels and dual-phase steels are the materials which fulfil the above-mentioned criteria. The application of high-strength sheets has led to the development of new materials joining techniques. Mechanical joining, such as clinching, is the innovative technique to join these progressive materials. Materials of different thicknesses can be joined by clinching. The paper focuses on the comparison of the properties of the joints made by clinching and resistance spot welding. The application of resistance spot welding is still the most used joining method in car body production. These properties were investigated by tensile test and metallographic observation. The HCT600X+ZF, HCT600X+Z and HX420LAD+Z steel sheets were used for the experiments. The results of tensile test show that the values of load-bearing capacity of clinched joints reached from 3900 N to 5900 N and the resistance spot welded joints reached the values of load-bearing capacity from 12000 N to 19500 N. In comparison to the resistance spot welded joints, the clinched joints reached from 32 to 48% of load-bearing capacity.

8

Influence of printing direction on 3D printed ABS specimens

Markiz Nassim, Horváth Eszter, Ficzere Péter

Production Engineering Archives

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2020

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Vol. 26, Iss. 3

127--130

EN

In the recent years, additive manufacturing became an interesting topic in many fields due to the ease of manufacturing complex objects. However, it is impossible to determine the mechanical properties of any additive manufacturing parts without testing them. In this work, the mechanical properties with focus on ultimate tensile strength and modulus of elasticity of 3D printed acrylonitrile butadiene styrene (ABS) specimens were investigated. The tensile tests were carried using Zwick Z005 loading machine with a capacity of 5KN according to the American Society for Testing and Materials (ASTM) D638 standard test methods for tensile properties of plastics. The aim of this study is to investigate the influence of printing direction on the mechanical properties of the printed specimens. Thus, for each printing direction ( and ), five specimens were printed. Tensile testing of the 3D printed ABS specimens showed that the printing direction made the strongest specimen at an ultimate tensile strength of 22 MPa while at printing direction it showed 12 MPa. No influence on the modulus of elasticity was noticed. The experimental results are presented in the manuscript.

9

Influence of Crimp and Inter-Yarn Friction on the Mechanical Properties of Woven Fabric under Uniaxial/Biaxial Tensile Loading

Huang Canyi, Cui Lina, Xia Hong, Qiu Yiping, Ni Qing-Qing

Fibres & Textiles in Eastern Europe

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2020

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Vol. 28, no. 6 (144)

43--52

EN

In the present research, a physical-geometric-feature of continuous yarn in a plain woven fabric was created and its FE model was analysed by considering the two key issues of woven fabric, the crimp and inter-yarn friction. The basic parameters of Young’s modulus of single yarn and the inter-yarn friction coefficient were investigated for practical fabrics in tensile and pull-out tests. FE analysis indicated that the stress-strain curves of the FE model were effective in evaluating the equivalent modulus of a woven fabric by comparing with a tensile experiment on Twaron CT® Plain Woven Fabric. In addition, a simplified three dimensional model of the unit cell of plain woven fabric (UCPW) was employed to quantitively investigate two important fabric characteristics – the crimp rate of the yarn and inter-yarn friction-to determine their influence on the mechanical properties of the fabrics. Furthermore, we used FE analysis to evaluate how the crimp rate and inter-yarn friction affected the mechanical properties by determining the equivalent modulus of single yarn and UCPW in both uniaxial and biaxial tensile loading. The stresses at representative nodal points and the mechanical interaction between yarns were also investigated from a microscopic perspective, and their deformation mechanisms were also analysed and discussed.

PL

W pracy stworzono fizyczno-geometryczną cechę przędzy ciągłej w gładkiej tkaninie i przeanalizowano jej model FE, biorąc pod uwagę dwa kluczowe zagadnienia tkaniny: karbikowatość i tarcie między przędzami. Zbadano podstawowe parametry: moduł Younga przędzy pojedynczej oraz współczynnik tarcia między przędzami. Analiza FE wykazała, że krzywe naprężenie-odkształcenie modelu FE były przydatne w ocenie tkaniny przez porównanie z eksperymentem rozciągania tkaniny Twaron CT® Plain Woven. Ponadto zastosowano uproszczony trójwymiarowy model komórki elementarnej z gładkiej tkaniny (UCPW) do ilościowego zbadania dwóch ważnych cech tkaniny: szybkości fałdowania przędzy i tarcia między przędzami – w celu określenia ich wpływu na właściwości mechaniczne tkaniny. Ponadto wykorzystano analizę FE, aby ocenić, w jaki sposób szybkość fałdowania i tarcie między przędzami wpłynęły na właściwości mechaniczne. Dokonano tego poprzez określenie równoważnego modułu pojedynczej przędzy i UCPW zarówno przy jednoosiowym, jak i dwuosiowym obciążeniu rozciągającym. Naprężenia w reprezentatywnych punktach węzłowych i mechaniczne interakcje między przędzami zbadano również z perspektywy mikroskopowej, a także przeanalizowano i omówiono ich mechanizmy deformacji.

10

Bond behavior of steel fiber-reinforced mortar (SFRM) applied onto masonry substrate

Zampieri Paolo, Simoncello Nicolò, Libreros Jaime Gonzalez, Pellegrino Carlo

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 3

409--428

EN

Masonry was the most used material during the last centuries to build constructions. Most of the existing masonry structures (buildings, bridges, etc.) were built without considering some important structural considerations that are important nowadays. Moreover, due to factors such as the increasing of service loads, materials aging, structural damage, etc., the existing masonry structures require strengthening interventions. The definition of optimal strengthening strategies using traditional and innovative materials is still an important issue of the scientific research. In fact, during the last decade, many researchers focused their attention studying innovative composites materials, such as fiber-reinforced polymers and fiber-reinforced cementitious matrix composites, for the strengthening of existing masonry structures. This research has focused on aspects such as the bond behavior between the substrate and the composite materials, the structural behavior of the strengthened masonry and concrete structures, and the compatibility and reversibility of these materials when bonded to existing substrates. In this study, the bond behavior of a composite material known as steel fiber-reinforced mortar (SFRM), recently used as for the strengthening of existing structures, applied onto masonry structures is analyzed experimentally and numerically. First, the material is characterized experimentally with the aim of getting insight on its behavior and applicability when applied as an innovative technique for the strengthening of masonry and to obtain mechanical parameters required for the numerical models. Mechanical properties of the SFRM studied included flexural and compressive strength, tensile strength, and residual flexural strength. The SFRM bond behavior on masonry substrates was evaluated by means of double shear lap tests. In addition, the experimental tensile and bond behavior of the SFRM is studied numerically through finite-element models validated using the results obtained during the experimental tests. Results show that if an adequate bonded length is provided, the SFRM can fully develop its tensile strength as detachment from the substrate is not observed.

11

The defect analysis of Inconel 738LC with computed tomography inspection

Ciećko Andrzej, Kamiński Łukasz, Wierzba Patrycja

Advances in Manufacturing Science and Technology

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2020

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Vol. 44, nr 3

80--83

EN

In the present paper, computed tomography (CT) inspection is shown. The CT inspection method allowed to rate the density of defects hidden inside a material, which has a significant role in the live material. The method allows to evaluate the reliability of tensile test’s results. In our analysis, the position of crack propagation was determined by CT, and the tensile test was performed to check the accuracy of the nondestructive method. The tensile tests were performed on Inconel 738LC [1] samples.

12

Structure, Texture and Tensile Properties of Ti6Al4V Produced by Selective Laser Melting

Konečná Radomila, Medvecká Denisa, Nicoletto Gianni

Production Engineering Archives

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2019

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Vol. 25

60--65

EN

Additive manufacturing has recently expanded its potential with the development of selective laser melting (SLM) of metallic powders. This study investigates the relation between the mechanical properties and the microstructure of Ti6Al4V alloy produced by SLM followed by a hot isostatic pressing (HIP) treatment. HIP treatment minimizes the detrimental influence of material defects. Tensile specimens produced with reference to specific building axes were prepared using a Renishaw A250 system. It has been found that the tensile strength and elongation depend on specimen building direction. Microstructural and textural characterizations were carried out to identify the source of differences.

13

Research of the dual phase steel DP450 properties from the forming aspects

Bilik Jozef, Tittel Viktor, Sobota Robert, Suba Roland

Hutnik, Wiadomości Hutnicze

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2019

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Vol. 86, nr 1

14--17

EN

The paper is focused on study of plasticity and formability of dual phase steel DP 450, which is used in automotive industry. The paper shows results from tensile test for plasticity determination and also results of technological tests for complex evaluation of formability. These consisted from Erichsen cup test, Fukui test and Schmidt test. The paper shows also results of microhardness measurement.

PL

Artykuł koncentruje się na badaniu plastyczności i odkształcalności stali dwufazowej DP 450, która jest stosowana w przemyśle motoryzacyjnym. W pracy przedstawiono wyniki prób rozciągania dla określenia plastyczności, a także wyniki testów technologicznych dla kompleksowej oceny odkształcalności. Składały się one z testu pucharowego Erichsena, testu Fukui i testu Schmidta. W pracy przedstawiono również wyniki pomiaru mikrotwardości.

14

Identification of the tensile damage of degraded carbon steel and ferritic alloy-steel by acoustic emission with in situ microscopic investigations

Lyasota Igor, Kozub Barbara, Gawlik Józef

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

274--285

EN

The paper presents results obtained from the destructive laboratory investigation conducted on materials from pressure vessels after long-term operation in the refinery industry. Tested materials contained structural defects, which arose from improper heat treatment during steel plate manufacturing. Detailed metallographic and chemical composition tests and static tensile tests were conducted. Next, complex tensile tests were conducted with simultaneous acoustic emission (AE) monitoring while observing microstructural changes by light microscopy. From the laboratory tests, the correlations between the AE signal parameters and material microstructural damage during the tensile tests were developed. The results will be used as a basis of new algorithms for the structural condition assessment of in-service pressure equipment.

15

Numerical modelling of resins used in stereolitography rapid prototyping

Miedzińska Danuta, Małek Ewelina, Popławski Arkadiusz

Applied Computer Science

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2019

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Vol. 15, no 4

16--26

EN

The presented research deals with the development of the numerical model for resins used for stereolithography (SLA) rapid prototyping. SLA is an additive method of production of models, prototypes, elements or parts of constructions with the use of 3D printing that covers photochemical processes by which light causes chemical monomers to link together to form polymers. Such method is very useful in design visualization, but also can be applied in numerical modelling for the purpose of validation and verifi-cation. In this application the resin strength parameters must be described and on the base of them the numerical material model is developed and validated. Such a study for SLA resins was presented in the paper.

16

The determination of mechanical properties of prosthetic liners through experimental and constitutive modelling approaches

Łagan S., Liber-Kneć A.

Technical Transactions

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2018

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Vol. 115, iss. 3

197--209

EN

The aim of the study was the estimation of the ability of hyperelastic material models for the fitting of experimental data obtained in the tensile testing of silicone liners used in lower-limb prosthetics. Three groups of liners were analysed: I – silicone liner, II – part of the liner in which the silicone has a fabric reinforcement, III – silicone liner with an outer covering material. Both longitudinal and circumferential samples were taken. The Neo-Hookean, Mooney-Rivlin and Ogden parameters of constitutive models of hyperelastic materials were calculated.

PL

Celem badań była ocena przydatności modeli materiałów hipersprężystych do dopasowania danych doświadczalnych uzyskanych w próbie rozciągania dla silikonowych linerów ortopedycznych stosowanych w protezach dolnych. Przeanalizowano trzy grupy: I – liner silikonowy, II – liner silikonowy z wewnętrznym wzmocnieniem, III – liner silikonowy z zewnętrznym wzmocnieniem. Wyróżniono dwa kierunki pobrania próbek: podłużny i obwodowy. Zidentyfikowano parametry określonych funkcji modeli konstytutywnych materiałów hipersprężystych: Neo-Hookean’a, Mooney-Rivlin’a i Ogden’a.

17

Optymalizowanie struktury i właściwości mechanicznych stali martenzytycznych przeznaczonych na wielkogabarytowe pierścienie

Pachutko B., Lulkiewicz J., Surma M., Ziółkiewicz S., Kajpust S.

Obróbka Plastyczna Metali

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2018

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T. 29, nr 4

315--330

PL

Duże zapotrzebowanie na odkuwki w postaci pierścieni dla różnych gałęzi przemysłu wymaga stosowania nowoczesnych stali martenzytycznych o właściwościach mechanicznych dostosowanych do konkretnego zastosowania. Aby sprostać wymaganiom rynku, powstała koncepcja projektu niskoodpadowej technologii kształtowania wielkogabarytowych pierścieni ze stali X20Cr13 i X10CrMoVNb9-1 o profilowanych pobocznicach. Liderem projektu jest firma Zarmen FPA. Jednym z etapów tego projektu jest opracowanie technologii obróbki cieplnej pierścieni. Wykonano badania mikrostruktury i właściwości mechanicznych (wg norm PN-EN ISO 6892-1:2016-09, PN-EN ISO 148-1:2017-02 i PN-EN ISO 6507-1:2007) na próbkach pobranych z odkuwek kutych swobodnie przy temperaturze 1110±20°C z redukcją wysokości materiału wsadowego 50% oraz obrobionych cieplnie w 2 wariantach: hartowanie stali X20Cr13 z temperatury 1020±10°C w oleju oraz odpuszczanie przy temperaturze 600°C i 700°C, hartowanie stali X10CrMoVNb9-1 z temperatury 1050±10°C w oleju oraz odpuszczanie przy temperaturze 650°C i 700°C. Materiałem wsadowym były wałki ϕ40x60 mm. Wykonano też badania porównawcze na próbkach pobranych z wałków w stanie dostawy hutniczej i poddanych obróbce cieplnej w tych samych warunkach co odkuwki. Wskaźniki Rp0,2 i Rm, zgodne z założeniami, otrzymano dla obu stali po odpuszczaniu próbek pobranych z odkuwek przy temperaturze 700°C, wynoszące odpowiednio: 660 MPa i 844 MPa dla stali X20Cr13 oraz 764 MPa i 893 MPa dla stali X10CrMoVNb9-1. Wydłużenie próbek z obu stali wyniosło 21%, a praca łamania KV2: 25 J dla stali X20Cr13 i 38 J dla stali X10CrMoVNb9-1. Planowana jest weryfikacja właściwości mechanicznych uzyskanych na próbkach pobranych z kutych wałków oraz z eksperymentalnie walcowanych pierścieni.

EN

The large demand for forgings in the form of rings for various branches of industry requires the application of modern martensitic steels with mechanical properties adapted to the specific application. To meet the requirements of the market, the first concept of low-waste forming technology for large-size rings made of X20Cr13 and X10CrMoVNb9-1 steel, with profiled side surfaces, was created. The leader of the project is Zarmen FPA. One of the stages of this project is the development of ring heat treatment technology. Tests of microstructure and mechanical properties (according to standards PN-EN ISO 68921:2016-09, PN-EN ISO 148-1:2017-02 and PN-EN ISO 6507-1:2007) were performed on samples collected from flat-die forgings at temperature 1110±20°C with 50% height reduction of the stock material and heat treatment in 2 variants: hardening of X20Cr13 steel from temperature 1020±10°C in oil and tempering at temperature 600°C and 700°C, hardening of X10CrMoVNb9-1 steel from temperature 1050±10°C in oil and tempering at temperature 650°C and 700°C. The stock material was ϕ40x60 mm shafts. Comparative tests were also performed on samples collected from shafts in the state as delivered from the mill and subjected to heat treatment under the same conditions as forgings. Indicators Rp0.2 and Rm, according to assumptions, were obtained for both steels after tempering of samples collected from forgings at temperature 700°C, and were equal to, respectively: 660 MPa and 844 MPa for X20Cr13 steel and 764 MPa and 893 MPa for X10CrMoVNb9-1 steel. Elongation of samples for both steels was 21%, and energy absorbed during fracture KV2: 25 J for X20Cr13 steel and 38 J for X10CrMoVNb9-1 steel. It is planned to verify mechanical properties obtained in samples collected from forged shafts and from experimentally rolled rings.

18

Effect of printing parameters on the mechanical properties of parts fabricated with open-source 3D printers in PLA by fused deposition modeling

Ouhsti M., El Haddadi B., Belhouideg S.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 4

895--907

EN

3D polymer-based printers have become easily accessible to the public. Usually, the technology used by these 3D printers is Fused Deposition Modelling (FDM). The majority of these 3D printers mainly use acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) to fabricate 3D objects. In order for the printed parts to be useful for specific applications, the mechanical properties of the printed parts must be known. The aim of this study is to determine the tensile strength and elastic modulus of printed materials in polylactic acid (PLA) according to three important printing parameters such as deposition angle, extruder temperature and printing speed. The central composite design (CCD) was used to reduce the number of tensile test experiments. The obtained results show that the mechanical properties of printed parts depend on printing parameters. Empirical models relating response and process parameters are developed. The analysis of variance (ANOVA) was used to test the validity of models relating response and printing parameters. The optimal printing parameters are determined for the desired mechanical properties.

19

Microstructure and properties of CuCr0.6 and CuFe2 alloys after rolling with the cyclic movement of rolls

Rodak K., Urbańczyk-Gucwa A., Jabłońska M. B.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 2

500--507

EN

This work is focused on the effect of rolling with cyclic movement of rolls (RCMR) on microstructure, mechanical properties and electrical conductivity of CuCr0.6 and CuFe2 alloys in states after applying different heat treatments. The mechanical properties were determined by using MST QTest/10 machine equipped with digital image correlation (DIC). Scanning transmission electron microscopy (STEM) was used for microstructural characterization. The RCMR processed alloys shows high mechanical strength (UTS:539 MPa for CuCr0.6 alloy and UTS:393 MPa for CuFe2 alloy) attributed to the high density of coherent precipitates (after aging at 500 °C/2 h) and ultrafine grained structure. Plastically properties as uniform elongation (Agt) was about (∼1%) for both alloys after RCMR deformation. The RCMR processing induces a significant reduction of the electrical conductivity for samples, which were quenched before deformation, but for samples which were subjected to aging before deformation, the electrical conductivity was restored thanks to precipitation process.

20

The evaluation of properties of mechanically clinched joints made of ferrous and non-ferrous materials

Kaščák Ľuboš, Spišák Emil, Kubík René, Majerníková Janka

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 1

162--170

EN

Nowadays, there are several reasons for the utilization of the sheets made of aluminum in the car body production. Besides decreasing the car body weight, there is a need to reduce fuel consumption of the vehicle as well as the environmental impact by lower production of emissions. Moreover, such reasons are mutually dependent or influence each other. The application of the aluminum sheets in hybrid car body production resulted in the need for innovative joining techniques, which could make it possible to successfully join sheets from aluminum alloys. Mechanical clinching is one of the new or innovative joining techniques, which belongs to cold-forming joining process, which makes it possible to join different kinds and thicknesses of sheets. Individual materials and thicknesses can be combined. The mechanically clinched joints are durable, and the joining process duration is very fast (duration of 1s) and does not have a distinctive impact on the environment; a protective layer of the sheets remains intact. The paper focuses on the evaluation of the properties of hybrid joints that were prepared by the single stroke clinching process with a rigid die. The hot-dip galvanized steel sheets DC06 and H220PD combined with the sheets from aluminum alloys EN AW 5754 (having different values of the hardness – H11, H22, and H24) and EN AW 6082 were used for joining. The results from experiments confirmed the mechanical clinching is the suitable technique for joining such combination of sheets. However, some considerations, such as the arrangement of the sheets about the punch and die, must be regarded.