Temat: mechanical defects - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

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

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Skocz do pozycji: 4.

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

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Skocz do pozycji: 5.

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

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Skocz do pozycji: 6.

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

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Skocz do pozycji: 7.

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

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Skocz do pozycji: 8.

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

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Skocz do pozycji: 9.

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

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