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    Wyświetlanie 1-9 z 9
    Tytuł:
    Mechanical Characterisation of Carbon Fibre-Reinforced Plastics with Defined Defects
    Charakterystyka mechaniczna wzmocnionych włóknem węglowym tworzyw sztucznych wraz ze zdefiniowaniem defektów
    Autorzy:
    Ashir, M.
    Bardl, G.
    Hahn, L.
    Nocke, A.
    Cherif, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/234248.pdf
    Data publikacji:
    2018
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    carbon fibre-reinforced plastics
    defects
    mechanical characterisation
    tworzywa sztuczne wzmocnione włóknami węglowymi
    wady
    charakterystyka mechaniczna
    Opis:
    A steadily increasing application of fibre-reinforced plastics in the field of lightweight construction has been observed in the course of the past two decades. Currently a major challenge in the growing high technology market is the quality assurance of manufactured fibre-reinforced plastic components. During different stages in the manufacturing process of fibre-reinforced plastics, defects of different types and sizes are enclosed in them, exerting a destructive influence on the performance of fibre-reinforced plastics in various practical applications in terms of strength, stiffness and brittleness. Thus the aim of this research project was to investigate the effect of defined local defects on the mechanical properties,such as tensile, flexural and impact properties, of fibre-reinforced plastics, in particular carbon fibre-reinforced plastics. Results show that these mechanical properties depend significantly on the type and size of defect.
    W ciągu ostatnich dwóch dekad zaobserwowano stale rosnące zastosowanie w dziedzinie lekkich konstrukcji tworzyw sztucznych wzmocnionych włóknami. Obecnie dużym wyzwaniem na rosnącym rynku wysokich technologii jest wyprodukowanie wysokiej jakości komponentów z tworzyw sztucznych wzmocnionych włóknami. Podczas różnych etapów procesu wytwarzania tworzyw sztucznych wzmacnianych włóknami pojawiają się defekty różnego rodzaju i rozmiarów wywierające destrukcyjny wpływ na działanie tworzyw sztucznych wzmacnianych włóknami w różnych praktycznych zastosowaniach pod względem wytrzymałości, sztywności i kruchości. Celem pracy było zbadanie wpływu określonych defektów lokalnych na właściwości mechaniczne, takie jak właściwości rozciągające, zginające i uderzeniowe. Wyniki pokazały, że właściwości mechaniczne zależą w znacznym stopniu od rodzaju i rozmiaru defektu.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2018, 6 (132); 126-132
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Relation between Porosity and Mechanical Properties of Al-Si Alloys Produced by Low- Pressure Casting
    Autorzy:
    Cais, J.
    Weiss, V.
    Svobodova, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/379877.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    mechanical properties
    castings defects
    porosity
    alloy AlSi7Mg
    intermetallic phases
    wady odlewów
    właściwości mechaniczne
    porowatość
    stop AlSi7Mg
    faza międzymetaliczna
    Opis:
    The aim of the research was to evaluate influence of porosity size on mechanical properties of AlSi7Mg0.3 (EN AC 42 100) alloy before and after thermal treatment. The castings from the same production type (forms used for tires production) were used for the analysis. They were casted using low-pressure casting technology. Since the negative influence of porosity on mechanical properties of Al alloys is generally known that there is no quantitative assessment. The relation of porosity size in the structure of AlSi7Mg0.3 alloy and its mechanical properties is verified and quantified in this research. Static tensile testing has proven the relation between porosity size in a structure of an Al material and its mechanical properties. The image analysis was applied in quantitative measurement of the porosity. The measurement was performed on prepared metallographic specimens. Porosity size is considered as a fraction of pore area to the total area of the analyzed specimen and is taken in percentage. As far as the theoretical part of the issue the possible causes of porosity formation and its influence on particular Al alloy types are described [1, 2, 3].
    Źródło:
    Archives of Foundry Engineering; 2014, 14, 1 spec.; 97-102
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Utilisation of the Coherence Analysis in Acoustic Diagnostics of Internal Combustion Engines
    Autorzy:
    Dąbrowski, Z.
    Dziurdź, J.
    Górnicka, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/176779.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic diagnostics
    internal combustion engines
    mechanical defects
    Opis:
    The leading thought of the present text is that the internal combustion engine noise – regardless of all possible inconveniences – is a good information carrier that allows for the explicit diagnostics of such subtle defect as the valve face decrement which is so small that it is in practice ‘unnoticeable’ by the standard diagnostic-controlling system of a passenger car. However, such defect at its further propagation can be much more dangerous. Thus, diagnosing its initial state is worth trying. This study is a continuation of investigations where efforts were undertaken to perform the efficient diagnostics on the bases of observations and analyses of mechanical vibrations of the engine head.
    Źródło:
    Archives of Acoustics; 2017, 42, 3; 475-481
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructure and Mechanical Properties of Rope Drum Casting
    Autorzy:
    Futáš, P.
    Pribulová, A.
    Mahút, D.
    Bartošová, M.
    Junáková, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/106955.pdf
    Data publikacji:
    2017
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    cast iron
    defects in casting
    rope drums
    metallurgical treatments
    mechanical properties
    Opis:
    Ductile iron is a high-carbon-containing iron-based alloy in which the carbon, as graphite, is present in a spheroidal shape. With its good mechanical properties, ductile iron approximates the properties of steel and the cost per unit of strength compared to other materials. With suitable metallurgical treatments, we can influence its microstructure and resulting properties. Incorrect manufacturing technology and metallurgical processes give rise to casting defects and decreased mechanical properties. The contribution is devoted to measures to prevent the occurrence of defects in the casting of rope drums and to achieve the required mechanical properties of these castings. The most-common defects in these castings are micro-shrinkages in casting heat centers and unsatisfactory mechanical properties such as tensile strength, yield strength, and elongation.
    Źródło:
    Journal of Casting & Materials Engineering; 2017, 1, 4; 75-79
    2543-9901
    Pojawia się w:
    Journal of Casting & Materials Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Effect of the Return Material Implementation into the Production of Silumin Casts on Technological and Economic Indicators of Production Process
    Autorzy:
    Gaspar, S.
    Majernik, J.
    Trytek, A.
    Podaril, M.
    Benova, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/2126917.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    HPDC
    product development
    quality management
    mechanical properties
    castings defects
    rozwój produktu
    zarządzanie jakością
    właściwości mechaniczne
    wady odlewów
    Opis:
    The production of high pressure die casts also brings difficulties regarding the processing of the waste material. It is mainly formed by runners, overflows and other foundry supplements used and, in the case of machines using the cold chamber, also the remainder from this chamber. As this material is often returned to the production process, we refer to it as return material. In the production process, it is therefore essential to deal with the proportion issue of return material against primary material that can be added to the melt to maintain the required cast properties. The submitted article monitors the quality properties of the alloy, selected mechanical properties of casts and porosity depending on the proportion of the return material in the melt. At the same time, the material savings are evaluated with regards to the amount of waste and the economic burden of the foundries. To monitor the above-mentioned factors, series of casts were produced from the seven melting process variants with a variable ratio of return to the primary material. The proportion ratio of return material in the primary alloy was adjusted from 100% of the primary alloy to 100% of the return material in the melting process. It has been proven that with the increasing proportion of the return material, the chemical composition of the melt changes, the mechanical properties of the alloy decrease and the porosity of the casts increases. Based on the results of the tests and analyzes, the optimal ratio of return and primary material in the melting process has been determined. Considering the prescribed quality of the alloy and mechanical properties, concerning the economic indicator of the savings, the ratio is set at 70:30 [%] in favor of the primary material.
    Źródło:
    Archives of Foundry Engineering; 2022, 22, 1; 69--76
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Obecność martwic na pniach drzew stojących a jakość i wartość surowca dębowego
    Necroses occurring on trunks of standing trees against the quality and the value of oak timber
    Autorzy:
    Michalec, K.
    Wąsik, R.
    Gruchała, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/989907.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    drzewa lesne
    dab
    drzewa stojace
    uszkodzenia mechaniczne
    martwice drewna
    drewno debowe
    jakosc
    timber damage
    defects
    mechanical injuries
    timber classification
    rot
    Opis:
    This paper aimed to evaluate the impact of necroses occurring on trunks of standing oak trees on their wood quality and value. The research was carried out in five study plots situated in the Meszcze Forestry, Piotrków Forest District (central Poland). The investigations covered: measuring the diameter at breast height of every injured tree with diameter ≥7 cm, estimating the length of the trunk fragment that should be cut off to remove the defect, the assessment of the quality and size of the 3−m butt−end fragment of a trunk, excluding the detected damage or rot (classification I), as well as the quality and size assessment of the same trunk fragment, though including the encountered defect (classification II). The theoretical volume of timber within the particular quality classes was computed (WAt, WBt, WCt and WDt). Afterwards, the real volumes (WAr, WBr, WCr and WDr) were compared with those of groups S2r and S4r. Based on the analysis of the quantity of damaged trees in the investigated trial plots, the lowest share of such specimens was recorded in the compartment 2a (1.6% of defective trees). Whereas, the highest share of damaged trees was encountered in the compartment 39a (8.5%). The timber of more valuable large−sized classes 'migrated', due to damages, to the groups of medium−sized timber (S2 or S4). With respect to the total volume of timber within the particular classes and groups, the greatest loss was reported in the WB class. The timber in question 'migrated' mostly to the group S2, though a part of it was classified to the group S4 as well. The established decrease in the timber value, due to damages to trunks, accounted for ca. 26%, which amounted to ca. 5.8 thous. PLN, in relation to the entire investigated material. The obtained results indicated the necessity to reduce the damages occurring in oak stands and remove the injured trees as soon as possible to avoid a significant depreciation and a value loss of raw wood.
    Źródło:
    Sylwan; 2015, 159, 09; 740-746
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Impact of the Presence of Foreign Bodies on Quality and Value of Oak Timber
    Autorzy:
    Michalec, Krzysztof
    Wąsik, Radosław
    Gach, Monika
    Powiązania:
    https://bibliotekanauki.pl/articles/27323539.pdf
    Data publikacji:
    2023
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
    Tematy:
    wood classification
    mechanical damage to wood
    wood defects
    metal fragments
    projectiles
    Opis:
    The paper discusses the impact of the presence of foreign bodies on the quality and value of oak timber as raw material. During the study, 109 oak bolts and logs with a total volume of 142.52 m 3 were measured and classified. The material for the study came from the Suchowice Forest District, within the Henryków Forestry Inspectorate (in the south-western part of Poland), and it was sampled from a tree stand located on the edge of the forest, where the largest concentration of rifle and artillery fire had occurred during World War II. As a result, the tree trunks contain significant amounts of shrapnel and projectiles. The length and diameter of each bolt and log were measured, and double classification was conducted: the first (I) classification took into account the presence of foreign bodies, whereas in the second (II) classification the presence of foreign bodies was disregarded. As a result of the conducted analyses, it was found that due to the presence of foreign bodies, all of the examined oak raw material was categorised as the worst quality class (D) timber. However, it was noted that during the second classification, where the presence of foreign bodies was not taken into account, a significant part of the raw material was upgraded to better quality classes, and only about 16% of wood remained in the worst, D class. Subsequently, it was calculated that the difference in the total value of the oak timber raw material classified by two methods amounted to approx. 204 thousand PLN (ca. € 43,514) – which was about 35% higher than the value calculated by the first method of classification.
    Źródło:
    Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2023, 66, 211; Art. no. 1644-3985.438.05
    1644-3985
    Pojawia się w:
    Drewno. Prace Naukowe. Doniesienia. Komunikaty
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Prediction of Fracture Stress with Regard to Porosity in Cast A356 Alloy
    Autorzy:
    Sahin, H.
    Atik, M.
    Tezer, F.
    Temel, S.
    Aydin, O.
    Kesen, O.
    Gursoy, O.
    Dispinar, Derya
    Powiązania:
    https://bibliotekanauki.pl/articles/2079787.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    A356
    casting defects
    mechanical properties
    porosity
    fracture stress
    Bifilm
    stop A356
    wady odlewnicze
    właściwości mechaniczne
    porowatość
    naprężenia
    Opis:
    Production of the defect-free casting of aluminium alloys is the biggest challenge. Porosity is known to be the most important defect. Therefore, many cast parts are subjected to several non-destructive tests in order to check their acceptability. There are several standards, yet, the acceptance limit of porosity size and distribution may change according to the customer design and requirements. In this work, the aim was targeted to evaluate the effect of size, location, and distribution of pores on the tensile properties of cast A356 alloy. ANSYS software was used to perform stress analysis where the pore sizes were changed between 0.05 mm to 3 mm by 0.05 mm increments. Additionally, pore number was changed from 1 to 5 where they were placed at different locations in the test bar. Finally, bifilms were placed inside the pore at different sizes and orientations. The stress generated along the pores was recorded and compared with the fracture stress of the A356 alloy. It was found that as the bifilm size was getting smaller, their effect on tensile properties was lowered. On the other hand, as bifilms were larger, their orientation became the dominant factor in determining the fracture.
    Źródło:
    Archives of Foundry Engineering; 2021, 21, 4; 21-28
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ultrasonic Assisted Active-Passive Filling Friction Stir Repairing to Eliminate Volume Defects
    Autorzy:
    Wang, Tao
    Gong, Xue
    Ji, Shude
    Xue, Gang
    Lv, Zan
    Powiązania:
    https://bibliotekanauki.pl/articles/2049431.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    friction stir repairing
    magnesium alloys
    defects
    ultrasonic
    mechanical properties
    Opis:
    Ultrasonic assisted active-passive filling friction stir repairing (A-PFFSR) was proposed to repair volume defects in the metallic parts. Sound joints without interfacial defects could be achieved. Firstly, the ultrasonic was beneficial to improving material flow and atom diffusion, and then eliminated kissing bond defects compared to conventional A-PFFSR joints. Secondly, the equiaxed grains were refined by ultrasonic vibration. Lastly, the repairing passes were reduced due to the ultrasonic, which decreased softening degree of the repaired joints. The maximum tensile strength of 150 MPa was achieved. Therefore, this strategy to repair the volume defects is feasibility and potential in the remanufacturing fields of aerospace and transportation.
    Źródło:
    Archives of Metallurgy and Materials; 2021, 66, 1; 217-222
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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