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1

The influence of adhesive material properties on the impact strength of adhesive block joints

Komorek Andrzej, Godzimirski Jan, Imiłowski Szymon

Technologia i Automatyzacja Montażu

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2023

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nr 4

20--27

EN

Adhesive joints are becoming increasingly popular in the construction of aircraft and other means of transport. Today, bonding is mainly used in the construction of helicopter fuselages, wings or lifting rotors. The increased popularity of bonding is forcing designers to seek new and improve research methods as well as enhancing the existing test methods which specify the static, fatigue or impact strength of joints. A variety of tests are used to determine the strength of structures, although new ones are constantly being sought so as to be applied more quickly and without specialised equipment. Current testing standards are also being modified in order to speed up and simplify the testing process, resulting in safer structures that use adhesive joints. The aim of the research presented in this paper was to test whether there is a relationship between the mechanical properties of adhesive materials and the impact strength of adhesive block joints with a cylindrical top element. Construction steel S235JR, commercially marked wear-resistant steel Raex 400 and 2017A aluminium alloy were used for the manufacture of the samples. From each material, 10 samples were prepared with upper elements of different diameters, namely: 17.8 mm, 12.6 mm and 8.9 mm. A pendulum hammer was used to determine the strength of the adhesive joint against dynamic load application. For the sake of the research, the authors used a modified PN-EN ISO 9653 with a mounted hammer equal to the maximum energy of 15 J. Lower failure energy was characteristic of samples made from material with a lower value of Young's modulus (aluminum alloy) and from steel with a lower yield strength. The joint failure energy grew with increasing the joint area, which was approximately parabolic.

PL

Połączenia klejowe są coraz bardziej popularne w konstrukcji statków powietrznych oraz innych środków transportu. Dziś klejenie stosuje się głównie przy budowie kadłubów, skrzydeł lub wirników nośnych śmigłowców. Zwiększenie popularności klejenia zmusza konstruktorów do poszukiwania nowych oraz udoskonalania istniejących metod badawczych określających wytrzymałość połączeń statyczną, zmęczeniową czy udarową. Stosuje się różnorodne badania by określić wytrzymałość konstrukcji, lecz wciąż poszukiwane są nowe, które można stosować szybciej oraz bez specjalistycznego wyposażenia. Także obecne normy badawcze są modyfikowane by przyśpieszyć oraz uprościć proces badawczy co skutkuje zwiększeniem bezpieczeństwa konstrukcji w których wykorzystano połączenia klejowe. Celem przedstawionych w artykule badań było sprawdzenie czy istnieje zależność pomiędzy właściwościami mechanicznymi materiałów klejonych i wytrzymałością udarową połączeń klejowych blokowych z górnym elementem o kształcie cylindrycznym. Do wykonania próbek wykorzystano stal konstrukcyjną S235JR, stal trudnościeralną o oznaczeniu handlowym Raex 400, oraz stop aluminium 2017A. Z każdego materiału przygotowano po 10 próbek z górnymi elementami o różnej średnicy, mianowicie: 17,8 mm, 12,6 mm oraz 8,9 mm. W celu określenia wytrzymałości połączenia klejowego na dynamiczne przyłożenie obciążenia wykorzystano młot wahadłowy. Do badania wykorzystano zmodyfikowaną normę PN-EN ISO 9653 z zamontowanym młotem o maksymalnej energii wynoszącej 15 J. Niższa energia niszczenia cechowała próbki wykonane z materiału o mniejszej wartości modułu Younga (stopu aluminium) oraz ze stali o mniejszej granicy plastyczności. Energia niszczenia połączeń rosła wraz ze wzrostem powierzchni spoin - w przybliżeniu parabolicznie.

2

Analysis of the properties of orthotropic composites in terms of their use in airframe repairs

Arkuszyńska Angelika, Godzimirski Jan, Rośkowicz Marek

Technologia i Automatyzacja Montażu

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2023

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nr 3

3--12

EN

The aim of the research was to determine the basic strength properties of orthotropic composites in terms of their use in the repair of aircraft airframes. The objects of the tests were three types of composites reinforced with carbon fibers: producedusing the wet method with a thickness of 2.5 mm, commercial with a thickness of 2 mm and commercial with a thickness of 7.3 mm. Specimens cut out from the first two types of materials were subjected to a static tensile test with a force applied in the direction of the fibers and at an angle of 45°, whichenabled the determination of tensile strength and modulus of elasticity. Specimens made of 7.3 mm thick composite were subjected to four-point bending and tensile tests to determine Young's modulus, compression and impact strength, also taking into account two directions of load application. The values of stresses and Young's modulus determined in this way indicate much lower strength and stiffness of orthotropic composites apart from the reinforcement fibers’ directions, which is the basis for replacing them with quasi-isotropic composites in repairs of aircraft airframes.

PL

Celem badań było wyznaczenie podstawowych właściwości wytrzymałościowych kompozytów ortotropowych w aspekcie wykorzystania ich w naprawach płatowców statków powietrznych. Obiektami badań były trzy rodzaje kompozytów zbrojonych włóknami węglowymi: wytworzony metodą na mokro o grubości 2,5 mm, komercyjny o grubości 2 mm oraz komercyjny o grubości 7,3 mm. Próbki wycięte z dwóch pierwszych rodzajów materiałów poddano statycznej próbie rozciągania siłą przyłożoną w kierunku ułożenia włókien oraz pod kątem 45°, co umożliwiło wyznaczenie wytrzymałości na rozciąganie oraz modułów sprężystości podłużnej. Próbki wykonane z kompozytu o grubości 7,3 mm poddano czteropunktowemu zginaniu oraz próbom rozciągania w celu określenia modułu Younga, ściskania oraz wytrzymałości udarnościowej także z uwzględnieniem dwóch kierunków przyłożenia obciążenia. Wyznaczone w ten sposób wartości naprężeń oraz modułów Younga wskazują na znacznie mniejszą wytrzymałość i sztywność kompozytów ortotropowych poza kierunkami ułożenia włókien zbrojenia, co stanowi podstawę do zastąpienia ich kompozytami quasi-izotropowymi w naprawach płatowców statków powietrznych.

3

Statistical methods in the analysis of strength parameters of epoxy-glass composites modified with rubber recyclate

Drewing S., Abramczyk N., Żuk D., Dyl T.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 117, nr 2

71--78

EN

Purpose The article presents a statistical analysis of strength parameters of newly developed epoxy-glass composite materials modified with the addition of rubber recyclate. Design/methodology/approach Three variants of materials with a percentage of recyclate content in the composite matrix of 3%, 5%, 7% and a reference variant without the addition of recyclate were used for the study. The samples were subjected to an impact test on a ZWICK RKP 450IR-GE impact hammer. Resilience measurement values were subjected to statistical analyses at the significance level α = 95%, such as: testing the normality of distributions with the Shapiro-Wilk test, testing differences between pairs with the Student's t-test for dependent groups, and testing ANOVA differences for independent groups. Findings The Shapiro-Wilk test confirmed that the resilience variables for all tested samples were in normal distributions; therefore the highest power parametric tests were used to test the differences. Using the Student's t-test, it was confirmed that between pairs of variables in configurations: standard sample with the modified sample, there were significant statistical differences in the distribution of resilience values for all samples. ANOVA confirmed significant changes in impact strength in 10 comparison variants. Research limitations/implications The obtained test results showed that in 9 compared cases, there were significant statistical differences, and in one case, there were no significant differences. Practical implications The performed statistical analyses confirmed their significant usefulness in the process of qualification of strength parameters for materials with high anisotropy, such as composites. Originality/value The manufactured products are innovative in terms of the method of using the addition of rubber recyclate as a filler for epoxy-glass composites. The use of static methods for their study also has practical value. It optimizes the analysis methods of the results of measurements of strength parameters of new composite materials.

4

The Melting Process and its Impact on the Properties of High-Chromium Cast Iron and the Economic Calculation

Mędoń Jan, Szczęsny Andrzej, Ziółkowski Eugeniusz, Guzik Edward, Czarny M., Kopyciński Dariusz

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

54--64

EN

The subject of this study is to show that the parameters of the melting process of high chromium cast iron affect the cost of casting and the properties of the cast iron. The analysis of the quality of the casting and its price was conducted in terms of the metal charge of high chromium cast iron. As is well known, in order to obtain the correct structure of the casting, and thus good strength properties, it is necessary to use clean batch components free of undesirable impurities. Unfortunately, the quality of the metal charge is proportional to its price. Thus, the use of expensive batch components offers the possibility of obtaining healthy and meeting the strength properties of castings. However, there is a flaw in this approach. And it is from the point of view of economics that production plants are forced to look for savings. Expensive feedstock materials are replaced by cheaper counterparts giving the possibility of obtaining castings with similar properties often, however, at the cost of increased inferior quality. It seems that a way out of this situation is to introduce a modification procedure into the alloyed iron manufacturing technology. The selected modifiers should affect the fragmentation of the structure of the primary austenite. At this point, it can be hypothesized that this will result in the elimination of hot cracking in high chromium cast iron. The industrial research carried out at the "Swidnica" Foundry Ltd. made it possible to show by means of the Althoff-Radtke method that by using the modification of the liquid metal of the so-called "inferior and cheaper" composition of the metal charge, a reduction in the occurrence of hot cracks and shrinkage cavities can be achieved. In addition, iron-niobium modification not only reduced the formation of casting defects in castings, but also slightly improved the impact strength of high-chromium cast iron. The work was written as part of an implementation PhD.

5

Reinforcement of compatibilized nanoclay/Inviya fibers to epoxy‑based glass fiber nanocomposites for high‑impact strength applications

Shelly Daksh, Nanda Tarun, Mehta Rajeev

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e84, 2023

EN

This research work is the first successful trial in which silanized nanoclay and compatibilized Inviya fibers were reinforced in epoxy-based glass fiber reinforced composites (EGFCs) resulting in significant improvements in impact strength without degrading tensile properties. Vacuum assisted resin infusion moulding (VARIM) technique was used for processing of multi-scale filler reinforced EGFCs. Inviya fibers were used, because of their high ‘elastic recovery’ and ‘stretchability’ (five times the original length) due to alternative flexible and rigid molecular structure. Nanoclay and Inviya fibers were subjected to compatibilization with different surface treatments. Compatibilization of fillers was confirmed through Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy-Energy-dispersive spectroscopy (FE-SEM/EDS) analysis. Nanoclay dispersion and morphology in EGFCs was ascertained through X-ray diffraction (XRD) and Transmission electron microscopy (TEM) analysis. Reinforcement of compatibilized Inviya fibres (First Method: maleic anhydride grafting, and Second Method: combination of phosphoric acid treatment followed by silanization) enhanced the impact strength by 132% and 150%, respectively, over the reference composition. FE-SEM micrographs of fracture surface of impact test specimens were utilized to identify the mechanisms causing improvement in impact behaviour.

6

The influence of the manufacturing method on the mechanical properties of the honeycomb core sandwich composite

Janiszewski Jacek, Przybyłek Paweł, Bieńczak Rafał, Komorek Łukasz, Schwarzenberg Miłosz

Technologia i Automatyzacja Montażu

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2022

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nr 4

20--33

EN

Reducing weight and fuel consumption is one of the main goals of modern aeronautical engineering. The most common materials to achieve this goal are composite layered materials, including the sandwich ones. High strength, stiffness and low density have made sandwich composites one of the fundamental materials of the aerospace industry. Sandwich-structured composites can be manufactured with a variety of methods, differing primarily in the manufacturing time, which translates into an overall cost of making a composite component. The research focused on three methods of manufacturing sandwich composite materials with a honeycomb core, differing in the number of operations, during which it was possible to obtain a finished composite panel (single-phase, two-phase and three-phase methods). The authors manufactured and examined composites with a honeycomb cover and two composite glass fibre-reinforced covers. The composites were made by means of the vacuum bag method. As a result of the conducted study, it was found that composites manufactured with the single-phase method have the shortest manufacture time as well as the lowest material consumption, however their strength properties are the lowest. The two-phase method requires a longer manufacture time and more material consumption, however it makes it possible to obtain a composite with higher strength compared with the single-phase method. The three-phase method has the longest composite manufacture time and the highest material consumption.

PL

Zmniejszenie masy i zużycia paliwa jest jednym z głównych celów współczesnej inżynierii lotniczej. Najpopularniejsze materiały, które pozwalają osiągnąć ten cel, to materiały kompozytowe warstwowe w tym przekładkowe. Wysoka wytrzymałość, sztywność i niska gęstość, sprawiły, że kompozyty przekładkowe stały się jednym z podstawowych materiałów przemysłu lotniczego. Kompozyty przekładkowe z wypełniaczem strukturalnym mogą być wytwarzane różnymi metodami, różniącymi się przede wszystkim czasem wytwarzania, co przekłada się na ogólny koszt wykonania elementu kompozytowego. W badaniach przeanalizowano trzy metody wytwarzania materiałów kompozytowych przekładkowych w wypełniaczem ulowym różniące się liczbą operacji podczas których uzyskano gotową płytę kompozytową (metoda jednofazowa, dwufazowa i trójfazowa). Wytworzono i badano kompozyty zbudowane z rdzenia ulowego oraz dwóch kompozytowych okładek wzmacnianych włóknami szklanymi. Kompozyty wykonano metodą worka próżniowego. W efekcie przeprowadzonych badań stwierdzono, że kompozyty wytworzone metodą jednofazową cechują się najkrótszym czasem produkcji jak i najmniejszym zużyciem materiałów, ale ich właściwości wytrzymałościowe są najniższe. Dwufazowa metoda wymaga dłuższego czasu produkcji i większego zużycia materiałów, natomiast pozwala uzyskać kompozyt o większej wytrzymałości w porównaniu do metody jednofazowej. Trójfazowa metoda cechuje się najdłuższym czasem wykonania kompozytu i największym zużyciem materiałów.

7

Influence of the shape of the impactor on residual strength, size and nature of damage to CFRP

Przybyłek Paweł, Komorek Andrzej, Kaczor Di Paola Simone Taddeo, Komorek Łukasz

Technologia i Automatyzacja Montażu

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2022

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nr 4

46--53

EN

The experimental tests presented in this work concern the impact resistance test and residual strength properties after an impact performed by a drop tower INSTRON CEAST 9340. The authors prepared samples of a composite material with a polymeric matrix L285 and H285 hardener, reinforced with eight ply fabric of carbon fibre. Two shapes of the impactor (spherical and V-shape) were used to perform the testing. The samples were impacted by three values of energy (10, 15, 20 [J]). Three-point bending tests were performed to the residual strength of the samples subjected to impact tests and compared to samples which had not been damaged earlier. The study showed differences in the influence of the shapes of the impactor on the nature of the composite damage. After the test, conclusions were drawn about the influence of the shape of the impactor on the area of composite damage and its character. Also, its influence on residual strength was described. Despite the clear differences in the area of damage to composites impacted by different impactors, this does not have a significant influence on the residual strength.

PL

Przedstawione w pracy badania eksperymentalne dotyczą badania udarności oraz właściwości wytrzymałości szczątkowej po uderzeniu wieżą zrzutową INSTRON CEAST 9340. Autorzy przygotowali próbki materiału kompozytowego z osnową polimerową L285 i utwardzaczem H285, wzmocnionego tkaniną ośmiowarstwową z włókna węglowego. Do badań wykorzystano dwa kształty impaktora (kulisty i V). Próbki były poddawane działaniu trzech wartości energii (10, 15, 20 [J]). Próby zginania trzypunktowego przeprowadzono do wytrzymałości szczątkowej próbek poddanych próbom udarności i porównano z próbkami, które wcześniej nie uległy uszkodzeniu. Badania wykazały różnice we wpływie kształtów impaktora na charakter uszkodzenia kompozytu. Po przeprowadzeniu badań wyciągnięto wnioski dotyczące wpływu kształtu impaktora na obszar uszkodzenia kompozytu i jego charakter. Opisano również jego wpływ na wytrzymałość resztkową. Pomimo wyraźnych różnic w obszarze uszkodzeń kompozytów pod wpływem różnych impaktorów, nie ma to istotnego wpływu na wytrzymałość szczątkową.

8

The effect of basalt knitted fabric on the properties of green epoxy resin

Jamshaid Hafsa, Rajput Abdul Waqar, Zahid Bilal, Memon Sanam, Qureshi Raja Fahad, Aslam Sarmad, Nadeem Muhammad

Polimery

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2022

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Vol. 67, nr 2

67--71

EN

The influence of basalt fabric on the tensile mechanical properties and the impact resistance of green epoxy resin was investigated. Composites with parallel arrangement of insert yarns had better properties than in the case of their perpendicular arrangement. The properties were also influenced by the number of layers of the fabric. The tensile strength and impact resistance of the composites were better than the commercially available side mirror covers due to the superior properties of the basalt fiber.

PL

Zbadano wpływ tkaniny bazaltowej na właściwości mechaniczne przy rozciąganiu i odporność na uderzenie „zielonej” żywicy epoksydowej. Kompozyty o równoległym ułożeniu przędzy charakteryzowały się lepszymi właściwościami niż te o prostopadłym ułożeniu. Na właściwości miała również wpływ liczba warstw tkaniny. Wytrzymałość na rozciąganie i odporność na uderzenie kompozytów były lepsze niż dostępnych na rynku osłon lusterek bocznych ze względu na dobre właściwości włókna bazaltowego.

9

Modyfikowanie nienasyconych żywic poliestrowych nanododatkami

Stępka Dominik

Inżynieria Materiałowa

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2022

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Vol. 43, nr 4

10--12

PL

W pracy przedstawiono różnego rodzaju podejście do kwestii modyfikacji żywic poliestrowych przy użyciu nanododatków. Poruszono zagadnienia nasiąkliwości kompozytów na bazie żywic, ich ognioodporności, a także udarności i wytrzymałości na zginanie. Zwrócono szczególną uwagę na metody z którymi wiąże się najbardziej korzystne rokowania.

EN

The paper presents a different approach to the modification of polyester resins with the use of nano-additives. The issues of absorbability of resinbased composites, their fire resistance, as well as impact strength and flexural strength were discussed. Particular attention was paid to the methods with the most favorable prognosis.

10

Spheroidal Cast Iron for Works at Low Temperature - Requirements, Structure, Properties, Control of the Production Process

Zych Jerzy, Jurga T., Mocek Jan, Myszka Marcin, Snopkiewicz Tomasz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

999--1005

EN

Two standardised grades of spheroidal cast iron determined in standard EN PN 1563-1997 as: EN-GJS-350-22LT (T=-40°C) and EN GJS 400-18LT (T=-20°C) are intended for work at low temperatures: -20 and -40°C. The main mechanical property of these cast iron grades is a high impact strength at a work temperature down to: -40°C. A series of controlled melts was performed to optimise the production technology of spheroidal cast iron, which in as-cast state is characterised by ferritic matrix (the best without any pearlite), fine precipitates of nodular graphite and high purity (without non-metallic inclusions). Variable structures of metal charges and various spheroidisation techniques (the modification methods) (slender ladle with a tight cover - Tundish technology as well as the technology with cored wire) were applied in the research. In order to obtain refinement of graphite precipitates and to achieve the ferritic matrix multistage inoculations of technologies were applied. Cast iron was subjected to refining to limit non-metallic inclusions since they decrease the impact strength. The production process of cast iron was controlled by the thermal derivative analysis at the stage of initial cast iron and after its secondary metallurgy (modification and inoculation). It was pointed out, that the reproducible production of cast iron for work at low temperatures was only possible when all elements of the technological process were strictly adhered to. It was pointed out, in the hereby paper, that: it should be strived to maintain Si content not higher than 2.50÷2.60%, which at producing spheroidal cast iron is sometimes difficult and requires using a lot of pig iron in the metal charge. For a fast assessment of the cast iron quality, concerning its impact strength, the proposed - in the hereby paper - index quality (IQu) can be applied. It is determined on the bases of measuring the cast iron hardness and propagation velocity of ultrasound wave.

11

Study on uniaxial impact compression characteristics of basalt fiber cement soil

Cao Hai, Zhang Xiangyang

Archives of Civil Engineering

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2022

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Vol. 68, nr 1

667--678

EN

In order to study the dynamic mechanical properties of cement soil, uniaxial impact compression tests with different strain rates of cement soil with no fiber and with 0.2% basalt fiber were carried out by using a 50 mm steel split Hopkinson pressure bar device. The test results show that the impact compressive strength, dynamic increase factor and peak strain increase with the increase of strain rate under the same basalt fiber content, showing obvious strain rate effect. The dynamic stress-strain curve of basalt fiber cement soil underwent elastic deformation stage, plastic deformation stage and failure stage. With the increase of strain rate, the degree of fracture of cement soil samples gradually increases, which shows that the number of fragments increases, the size decreases and tends to be uniform. After adding basalt fiber in cement soil, the crack can be delayed, the degree of fracture is smaller than that without fiber and the plasticity of the samples is enhanced. It shows that basalt fiber can improve the impact compressive strength of cement soil.

12

Utilization of wrightia tinctoria nano seed fibers as a reinforcement in the preparation of epoxy-based composites

Syed Habibunnisa, Nerella Ruben, Madduru Sri Rama Chand, Reddy S Raja Gopal

Acta Innovations

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2022

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no. 45

5--17

EN

Natural seed fiber reinforced composite materials are replacing many conventional ones because of their excellent properties, less weight, easy availability, etc. Composite materials are used in many areas because of their superior features. Mechanical property is one of the vital parameters for choosing the material. The current investigation has revealed an importance of recently well-known Wrightia tinctoria nano seed fibers (WTNSFs), which are extracted physically. Wrightia tinctoria nano seed fiber reinforced composite was prepared with the epoxy resin by hand layup method. Epoxy resin is easy to handle and available at low cost. Mechanical tests are conducted reinforced composites of plain epoxy and WTNSFs to obtain strength properties like tensile, flexural, impact. Water absorption tests also performed on composites. Here, the developed composites are easy to handle, offered economically, and used primarily in marine applications due to less water absorption and good wax content. A comprehensive description of different tests and the properties of WTNSFs are studied and compared with the other existing natural fibers. This work showed that 35% combination of WTNSFs reinforced epoxy matrix offers enhanced mechanical properties with minimum water absorption compared with plain epoxy composites.

13

Impact of Microorganisms on Mechanical Properties Changes of Composite Materials with Sawdust as Organic Filler

Mazur Piotr, Szuszkiewicz Jarosław

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2021

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nr 24(1)

5--11

EN

The beginning of the XXIst century is characterized by rapid development of polymer materials, including polymer composite materials, which consist of a natural organic filler (wood flour, sawdust, cellulose fiber, flax fiber, sisal fiber) and reinforcement carrier (polymer). In case of that kind of the fillers under the influence of weathering (humidity, temperature) they might be subject to biodegradation due to effect of microorganisms, including funguses, which are responsible for degradation of natural organic fillers. In case of the low melting temperature polymers (e.g. PE-LD) the processing temperature does not entirely eliminate some of the fungal spores. The paper has presented the research results of twelve months. The development of the microorganisms in the natural conditions was examined in a pure filler (sawdust) as well as in a composite. Simultaneously, change of one of the fundamental strength properties, which is the impact strength, was being tested. For the investigated composite the PE-LD as the matrix and a sawdust mixture of pine, larch and oak were used. The sawdust formed the composite in 30% vol. The research results confirmed that in the natural conditions the microorganisms development depends on weathering which varies in the time of the year. The value of the V notch impact strength changed from 12.5 kJ/m2 for the composite in initial phase to the value of 6.7 kJ/m2 after twelve months operation, which is close to 54%.

14

Influence of FFF process parameters and macrostructure homogeneity on PLA impact strength

Bączkowski Michał, Marciniak Dawid, Bieliński Marek

Polimery

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2021

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T. 66, nr 9

480--483

EN

The article presents studies of the additive manufacturing printing parameters influence on the impact strength of PLA samples obtained by the fused filament fabrication (FFF) method. Two process variables were taken into account in the research program: the height of the printed layer and the printing temperature. An optical microscope was used to analyze the cross-section image (breakthrough) of the samples. The impact strength was determined at −40°C and 23°C. Selected geometric features of the macrostructure (uniformity and thickness of individual layers, voids) determined on the basis of the sample cross-section image analysis, enhanced the possibility of assessing the PLA impact strength, depending on the adopted process variables and the temperature at which the experiment was carried out.

PL

W artykule przedstawiono badania wpływu parametrów druku addytywnego na udarność próbek z PLA otrzymanych metodą FFF (fused filament fabrication). W programie badań uwzględniono dwie zmienne procesowe: wysokość drukowanej warstwy i temperaturę druku. Do analizy obrazu przełomu próbek wykorzystano mikroskop optyczny. Oznaczono udarność w temperaturze -40°C oraz 23°C. Wybrane cechy geometryczne makrostruktury (równomierność i grubość poszczególnych warstw, puste przestrzenie) wyznaczone na podstawie analizy obrazu przekroju próbek, pogłębiły możliwość oceny udarności PLA w zależności od przyjętych zmiennych procesowych, a także temperatury w jakiej zrealizowano eksperyment.

15

A comparison of some properties of the computer controlled nitriding process versus carburizing

Senatorski Jan, Mączyński Paweł, Tacikowski Jan

Inżynieria Powierzchni

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2021

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nr 1

25--35

EN

A comparison is presented of the nitriding and carburizing processes. Traditional gas nitriding, despite its several advantages over carburizing, has still not achieved its due popularity. The key factor is inadequate process control. An industrial-scale computerized system, employing the nitriding potential as the fundamental controlling parameter, can produce repeatable, superior nitriding results, limiting layer brittleness and enhancing usable properties. Results obtained showed that nitriding layers match carburized layers in fatigue, while exceeding them in both impact strength and wear resistance. The superiority of the computer-controlled process over traditional nitriding is illustrated by results of wear testing. The advent of controlled nitriding makes this process a viable alternative to carburizing.

PL

W niniejszej pracy porównano procesy azotowania oraz nawęglania. Tradycyjne azotowanie gazowe, pomimo szeregu zalet w stosunku do nawęglania, nie zyskało jeszcze wystarczającego rozpowszechnienia. Głównym powodem tego stanu rzeczy jest niewystarczająca kontrola procesu. W skali przemysłowej system sterowania komputerowego stosowany w odniesieniu do potencjału azotowego jako podstawowego parametru kontrolnego, jest wystarczający i nadaje się do realizacji powtarzalnej produkcji zapewniającej korzystne wyniki azotowania, ograniczającej kruchość warstw uzyskanych w tym procesie, a także zwiększający ich własności użytkowe. Uzyskane wyniki wskazują, że warstwy azotowane dobrze sprawują się w warunkach narażenia na zmęczenie, w których przewyższają zarówno oddziaływania udarnościowe, jak i odporność na zużycie przez tarcie. Przewagę procesu sterowanego komputerowo nad procesem tradycyjnego azotowania dobrze ilustruje próba odporności na zużycie przez tarcie. Stosowanie kontrolowanego procesu azotowania sprawia, że proces ten jest bardzo korzystną alternatywą procesu nawęglania.

16

Influence of fibre loading and surface treatment on the impact strength of coir polyester composites

Karthikeyan S.

Archives of Materials Science and Engineering

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2021

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Vol. 107, nr 1

16--20

EN

Purpose: In this work, coir fibre with varying fibre content was selected as reinforcements to prepare polymer-based matrices and the problem of reduced fibre-matrix interfacial bond strength has been diluted by chemical treatment of coir fibres with alkali solution. Design/methodology/approach: The effect of fibre loading, solution concentration and soaking time on the impact strength of the composites were analyzed using statistical techniques. Response Surface Methodology (RSM) approach was used to model and optimize the impact properties of coir-polyester composites. Findings: The impact strength of coir fibre reinforced polyester composite depends mainly on the fabrication parameters such as fibre-polyester content, soaking time, concentration of soaking agent and adhesive interaction between the fibre and reinforcement. Research limitations/implications: The mechanical properties of any coir polyester composite depend on the nature bonding between the fibre and reinforcement. The presence of cellulose, lignin on the periphery of any natural fibre reduces the bonding strength of the composite. This limitation is overcome by fibre treatment over sodium hydroxide to have better impact properties. Practical implications: Now days, natural fibre reinforced composites are capable of replacing automotive parts, subjected to static loads such as engine Guard, light doom, name plate, tool box and front panels etc. These materials can withstand any static load due to its higher strength to weight ratios. Originality/value: The effect of fibre loading, solution concentration and soaking time on the impact strength of the composites were analyzed using statistical techniques. Response Surface Methodology (RSM) approach was used to model and optimize the impact properties of coir-polyester composites. The impact strength of NaOH impregnated coir fibre reinforced polyester composites was evaluated.

17

The calculation of stress intensity factor steel of railway wheels

Vakulenko Igor, Proydak Svetlana, Askerov Hangardas

Zeszyty Naukowe. Transport / Politechnika Śląska

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2020

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z. 109

187--193

EN

From an analysis of the dependence complex of carbon steel properties on structural parameters, it was found that for an isostructural state, the influence of austenite grain size on impact strength exceeds the dependence on carbon content. As a result of explaining correlation relationships between individual mechanical characteristics, to evaluate critical stress intensity factor, a relationship is proposed based on the use of impact strength. The proportionality coefficient in proposed dependence is determined by ratio of elongation to narrowing at tensile test.

18

Production technology and mechanical properties of a new grade of steel for forgings with increased strength and impact strength

Burdek Marek, Marcisz Jarosław, Stępień Jerzy

Journal of Metallic Materials

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2020

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Vol. 72, no. 4

15--21

EN

The study involved the development of the basics of production technology and the testing of the mechanical properties of a new grade of steel for forgings with increased strength and impact strength, intended for special products. The scope of the tests included a proposal for a new steel composition along with the production of ingots and its further processing into forgings in industrial conditions, using an input with various dimensions of the cross-section, proposed as a result of numerical calculations, including the performance of heat treatment in two variants. As a result of tests and analyses, it was found that the proposed technology enables the production of semi-finished products with the assumed level of strength and impact strength.

PL

Opracowano podstawy technologii produkcji oraz przeprowadzono badania właściwości mechanicznych nowego gatunku stali na odkuwki o podwyższonej wytrzymałości i udarności z przeznaczeniem dla wyrobów specjalnych. Zakres badań obejmował propozycję nowego składu stali wraz z wykonaniem wlewków i jej dalszym przetwarzaniem na odkuwki w warunkach przemysłowych, wykorzystując wsad o różnych wymiarach przekroju poprzecznego zaproponowanych w wyniku obliczeń numerycznych łącznie z wykonaniem obróbki cieplnej w dwóch wariantach. W wyniku badań i analiz stwierdzono, że zaproponowana technologia umożliwia uzyskanie półwyrobów o założonym poziomie wytrzymałości i udarności.

19

The Morphology of Impact Fracture Surfaces in Manganese Cast Steel Modified by Rare Earth Elements

Kasińska J.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

89--94

EN

The morphology of G20Mn5 specimens made of non-modified and rare earth metals (REM) modified cast steel was investigated. Molten metal was treated with a cerium-rich mischmetal contain 49.8% Ce, 21.8% La, 17.1% Nd, 5.5% Pr and 5.35% other rare earth metals making up the balance. The melting, quenching (920°C/water) and tempering (720°C/air) were performed under industrial conditions. Analysis included G20Mn5 cast steel fracture specimens subjected to Charpy V-notch impact testing at 20°C, -30°C and -40°C. The purpose of the analysis was to determine the influence of REM on the microstructure and mechanical properties of G20Mn5 cast steel and the REM effect on the morphology, impact strength and character of the fracture surfaces. In addition, a description of the mechanism by which fracture occurred in the two materials was proposed. The author demonstrated the beneficial effects of adding REM to molten steel, manifested by a 20 - 40% increase in impact toughness, depending on test temperature, as compared to the non-modified cast steel. Important findings included more than 100% increase in impact strength in comparison with the required impact toughness of 27J at -40C for heat treated steels (EN 10213).

20

Multimetal Stahl 1018 Composite – Structure and Strength Properties

Kalisz D., Arustmian A.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

77--82

EN

The series of experiments was performed on commercial polymeric composite material MultimetalStahl 1018. Strength tests were performed to determine the yield point of the material. The composite had the highest hardness at a temperature of 20°C. Hardness and microhardness were determined in further experiments. The adhesiveness of the material to metal surfaces and impact strength were also analyzed. The scanning electron microscopy and X-ray microanalysis methods were used for analyzing the microstructure of the material. Chemical composition of selected areas was analyzed, which allowed for a preliminary identification of metallic elements content in the composite. The microstructure of composite is highly non-homogeneous and particular phases are highly elongated and angular. The analyzed phase was enriched with silicon, aluminium, magnesium, iron and vanadium other phases enriched with metallic elements, e.g. molybdenum, titanium, vanadium and also oxygen as well as traces of cadmium and chromium. The results were presented in the form of photos and illustrations. The results confirmed the applicability of the composite as a binder for fixing mechanical and foundry devices.