Autor: Lee, Y.-C. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Structural Properties and Mechanical Behavior of the 2 Step-Reinforced Al-Si/SiCp Metal Matrix Composite by Titanium-Fiber
Autorzy:: Oak, J.-J.
Lee, Y. C.
Park, Y. H.
Powiązania:: https://bibliotekanauki.pl/articles/356010.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: metal matrix composite
sintering
Ti fiber
mechanical properties
diffusion
Opis:: In this study, the newly designed Al-9Si/SiC particles (SiC_p) + Ti-fiber (2step-reinforced Al-9Si alloy matrix) metal matrix composites (MMCs) were fabricated by hot-pressing sintering at 560°C. 2step-reinforced Al-based MMCs were characterized by thermal shrinkage, phase transition, microstructure and tensile strength. The addition of Ti-fiber reduced thermal shrinkage was caused by temperature difference in sintering process as well as enhanced assistance for tensile strength and plastic deformation at room temperature. Experimental results reveal that the 2step-reinforcment sintering by ceramic and metal has a significant effect to increase interface bonding in boundary of each component material and the improved mechanical properties were due to the influence of interfacial product by diffusion. Tensile strength and elongation at room temperature by 2step-reinforcement were improved in 19.5% and 26.2% more than those of Al-9Si/SiC_p, respectively. Especially, it reveals that diffusion direction may be varied by sintering methods at low temperature in this study.
Źródło:: Archives of Metallurgy and Materials; 2017, 62, 2B; 1089-1097
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Finite element analysis of three-point bending of a T-beam structural biaxial highly oriented polymer material
Analiza metodą elementów skończonych zginania trójpunktowego belki teowej wykonanej z wysoko zorientowanego dwuosiowo materiału polimerowego
Autorzy:: Wei, C.-L.
Chang, Y.
Lee, Y.-C.
Lee, R.
Luo, T.-W.
Chen, J.-H.
Powiązania:: https://bibliotekanauki.pl/articles/946988.pdf
Data publikacji:: 2018
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:: solid phase processing
highly oriented polymer (HOP)
orthotropic materials
T-beam
three-point bending
finite element
proces w fazie stałej
wysoko zorientowany polimer
materiały ortotropowe
belka teowa
zginanie trójpunktowe
elementy skończone
Opis:: Polymers with biaxial aligned molecular chains are also orthotropic materials, which are characterized by high tensile strength and low shear strength in the length direction. When orthotropic materials are used as structural shapes with poor shear strength, they are likely to undergo premature failure under shear stress. Therefore, in three-point bending, the cross-section of the entire profile not only bears tensile stress and compressive stress in the length direction, but also simultaneously exhibits shear stress. This study analyzes the distribution of tensile stress, compressive stress and shear stress in the length direction of highly oriented polymers (HOP) by finite element analysis to find the most suitable length-to-height ratio for these materials when used as structural shapes. The finite element analysis software, Abaqus, is utilized to simulate HOP T-beam to analyze the load stress of a T-beam. With a fixed cross–section area, as the length of the material changes, its shear strength also changes. Accordingly, the order of occurrence of tensile failure and shear failure can be investigated. The simulation reveals that when the length-to-height ratio is between 4 : 1 and 20 : 1, a zone of stress in which tensile failure and shear failure occur can be found. This result can be exploited in the design and development of structural beam.
Polimery o dwuosiowo zorientowanych łańcuchach makrocząsteczek są materiałami ortotropowymi, wykazującymi dużą wytrzymałość na rozciąganie oraz niewielką wytrzymałość na ścinanie w kierunku długości. Elementy konstrukcyjne wytworzone z materiału ortotropowego o małej wytrzymałości na ścinanie są podatne na przedwczesne uszkodzenie pod wpływem naprężeń ścinających. Przy zginaniu trójpunktowym w przekroju ich profilu występują zarówno naprężenia rozciągające i ściskające w kierunku podłużnym, jak i naprężenia ścinające. Metodą elementów skończonych analizowano rozkład naprężeń rozciągających, ściskających i ścinających w kierunku podłużnym wysoko zorientowanych polimerów (HOP) w celu określenia optymalnego stosunku długości do wysokości w kształtach konstrukcyjnych. Do symulacji naprężeń obciążeniowych w zginaniu trójpunktowym belki teowej wykorzystano program komputerowy Abaqus. Stwierdzono, że przy stałej powierzchni przekroju poprzecznego belki jej wytrzymałość na ścinanie zmienia się wraz ze zmianą długości. Badano również kolejność występowania uszkodzeń pod wpływem działania sił rozciągających i ścinających. Symulacja wykazała, że przy stosunku długości do wysokości w zakresie od 4 : 1 do 20 : 1 występuje strefa naprężeń, w której mogą się pojawiać uszkodzenia w wyniku rozciągania lub ścinania. Uzyskane wyniki można wykorzystać w projektowaniu i optymalizacji belek konstrukcyjnych.
Źródło:: Polimery; 2018, 63, 3; 219-223
0032-2725
Pojawia się w:: Polimery
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Characterization Of The Graded Microstructure In Powder Sintered Porous Titanium
Charakterystyka gradientowej mikrostruktury porowatego tytanu spiekanego z proszku
Autorzy:: Oak, J.-J.
Bang, J. I.
Bae, K.-C.
Kim, Y. H.
Lee, Y. C.
Chun, H. H.
Park, Y. H.
Powiązania:: https://bibliotekanauki.pl/articles/356239.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: titanium
powder metallurgy
porous structure
sintering
biomaterial
tytan
metalurgia proszków
struktura porowata
spiekanie
biomateriał
Opis:: The proposed sintering process produce porosity and functional graded microstructure in the sinterd titanium powders. Titanium powders with different micro sizes were sintered at the proposed temperature region at 1200 and 1300°C for 2h. The apatite-forming on the graded microstructure is observed by immersion test in Hanks balanced salt soluion at 37°C. Sintering condition of titanium powders is estimated by thermogravitmetry-differential thermal analysis (TG-DTA). The synthersied surface structures and apatite-forming ability were characterized by a field emission scanning electron microscopy (FE-SEM) observation and energy dispersive X-ray spectroscopy (EDS) analysis. As results, these graded microstructure of sintered porous titanium powders reveals apatite-forming ability as osseointegration by calcification in Hanks balanced salt soluion(HBSS) at 37°C.
Źródło:: Archives of Metallurgy and Materials; 2015, 60, 2B; 1265-1269
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A Study Of The Die Roll Height Of SHP-1 And SCP-1 Materials In The Fine Blanking Process
Badanie wysokości deformacji krawędzi wycinanych elementów ze stali SHP-1 i SCP-1 procesie wykrawania
Autorzy:: Lee, C. K.
Kim, Y. C.
Powiązania:: https://bibliotekanauki.pl/articles/356499.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: die roll
fine blanking
SCP-1
share speed
SHP-1
v-rings
krawędzie
wykrawanie
szybkość działania
deformacja
Opis:: The height of the die roll, the distance of the V-ring, and the shear rate were varied with the aim of investigating the effects of the applied changes on the fine blanking line in a cold-rolled and a pickled steel sheet, referred to as SCP-1 and SHP-1, respectively. Both materials consisted primarily of a ferrite phase with small amounts of impurities including F, Mn, and Cr. The distance was found to be a very important factor in controlling the shear of the V-ring in the fine blanking process. When the position of the V-ring was set at distances of 1.5 mm and 2 mm, the die roll height increased with increasing shear speeds from 6.4 m/min to 10 and 16 m/min. Analysis of the influence of the shear rate revealed that low rates resulted in the lowest die roll heights since the flow of material was effectively inhibited.
Źródło:: Archives of Metallurgy and Materials; 2015, 60, 2B; 1397-1402
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: A Study on Changes in Thickness of STS304 Material in the Progressive Drawing Process
Autorzy:: Lee, C. K.
Kim, Y. C.
Powiązania:: https://bibliotekanauki.pl/articles/356710.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: body thickness
drawing
flange thickness
corner roundness
material thickness
Opis:: In the drawing process, the roundness of corners in the punch and the die are very important factors in determining the thicknesses of the product. The results clearly revealed that the thickness of a flange was increased and the thickness of body parts reduced when the roundness of the die entrance was small. The material thickness of the top part was decreased when the corner roundness of the punch was large. The smooth inflow of materials was found to have a significant effect on the thickness during the post-process. The compressive strength of STS 304 material exhibited a higher value compared with other processing methods. Moreover, we clearly observed the corner roundness of the punch and the die to be a very important factor for STS 304 materials.
Źródło:: Archives of Metallurgy and Materials; 2017, 62, 2B; 1319-1323
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Microstructure Evolution of Tungsten-Based ODS Alloys Reinforced with the γ(Ni, Fe) Phase by a Secondary Ball Milling Method
Autorzy:: Chen, C.
Zeng, Y.
Lee, J.
Powiązania:: https://bibliotekanauki.pl/articles/1375180.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 81.20.Ev
81.20.Wk
81.07.Bc
81.05.Ni
Opis:: In the current study, $W-5Ni-2Fe-Y_2O_3$ model alloys were produced using a high-energy planetary ball mill. The presence of the γ(Ni, Fe) phase is favored with respect to material properties in this alloy. Therefore, a secondary ball milling method was introduced to obtain a fine and uniformly distributed γ(Ni, Fe) phase. Phase development of mechanical alloyed powders was investigated by X-ray diffraction. The results show that the formation of the γ(Ni, Fe) phase was found after 18 h of a pre-milling procedure. A further secondary milling method produced a uniform microstructure with grain refinement. TEM results also show changes in the lattice parameters of the tungsten and γ(Ni, Fe) phase associated with the solid solubility limits in the alloy produced by secondary ball milling.
Źródło:: Acta Physica Polonica A; 2014, 126, 4; 907-911
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Grip Force and Heart Rate Responses to Manual Carrying Tasks: Effects of Material, Weight, and Base Area of the Container
Autorzy:: Lee, T. H.
Tseng, C. Y.
Powiązania:: https://bibliotekanauki.pl/articles/91134.pdf
Data publikacji:: 2014
Wydawca:: Centralny Instytut Ochrony Pracy
Tematy:: liquid
solid
carriage
manual materials handling
pracownik fizyczny
chwyt
transport ręczny
Opis:: This study recruited 16 industrial workers to examine the effects of material, weight, and base area of container on reduction of grip force (ΔGF) and heart rate for a 100-m manual carrying task. This study examined 2 carrying materials (iron and water), 4 carrying weights (4.4, 8.9, 13.3, 17.8 kg), and 2 base areas of container (24 ´ 24 cm, 35 ´ 24 cm). This study showed that carrying water significantly increased ΔGF and heart rate as compared with carrying iron. Also, ΔGF and heart rate significantly increased with carrying weight and base area of container. The effects of base area of container on ΔGF and heart rate were greater in carrying water condition than in carrying iron condition. The maximum dynamic effect of water on ΔGF and heart rate occurred when water occupied ~60%–80% of full volume of the container.
Źródło:: International Journal of Occupational Safety and Ergonomics; 2014, 20, 3; 377-383
1080-3548
Pojawia się w:: International Journal of Occupational Safety and Ergonomics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Non-parametric machine learning methods for evaluating the effects of traffic accident duration on freeways
Autorzy:: Lee, Y.
Wei, C.-H.
Chao, K.-C.
Powiązania:: https://bibliotekanauki.pl/articles/223569.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: accident on freeway
accident duration
effect evaluating
correlation
artificial neural networks
k-nearest neighbour method
wypadek na autostradzie
czas trwania wypadku
ocena skutków
korelacja
sztuczne sieci neuronowe
metoda najbliższego sąsiada
Opis:: Traffic accidents usually cause congestion and increase travel-times. The cost of extra travel time and fuel consumption due to congestion is huge. Traffic operators and drivers expect an accurately forecasted accident duration to reduce uncertainty and to enable the implementation of appropriate strategies. This study demonstrates two non-parametric machine learning methods, namely the k-nearest neighbour method and artificial neural network method, to construct accident duration prediction models. The factors influencing the occurrence of accidents are numerous and complex. To capture this phenomenon and improve the performance of accident duration prediction, the models incorporated various data including accident characteristics, traffic data, illumination, weather conditions, and road geometry characteristics. All raw data are collected from two public agencies and were integrated and cross-checked. Before model development, a correlation analysis was performed to reduce the scale of interrelated features or variables. Based on the performance comparison results, an artificial neural network model can provide good and reasonable prediction for accident duration with mean absolute percentage error values less than 30%, which are better than the prediction results of a k-nearest neighbour model. Based on comparison results for circumstances, the Model which incorporated significant variables and employed the ANN method can provide a more accurate prediction of accident duration when the circumstances involved the day time or drunk driving than those that involved night time and did not involve drunk driving. Empirical evaluation results reveal that significant variables possess a major influence on accident duration prediction.
Źródło:: Archives of Transport; 2017, 43, 3; 91-104
0866-9546
2300-8830
Pojawia się w:: Archives of Transport
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Development of a high-speed air bearing spindle
Autorzy:: Ha, Y.-H.
Lee, D.-W.
Hwang, Y.-K.
Lee, C.-M.
Powiązania:: https://bibliotekanauki.pl/articles/1429126.pdf
Data publikacji:: 2008
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: aerostatic bearing
metal foam
porous thrust bearing
porous radial bearing
Opis:: This paper investigates an air spindle with both radial and thrust air bearings of newly developing one-directional porous materials. At present, orifice type and porous type are adopted for thrust air bearings. Orifice type thrust air bearing is fabricated by machining several micro-holes on a bearing pad bearing, permeability significantly affected by particle size and machining conditions is an important factor of performance, but it is hard to c porosities is suggested. It has many micro-porosities through axial direction, so stable and plenty of air can be supplied to the thrust bearing pad. A radial air bearing also can be substituted by a radial direction porous bearing as the same reason. In case of driving parts, built-in motor type is widely applied. But it needs additional cooling parts to drop heat from a motor. So application of an air turbine drive with light-weight shaft is suggested and additionally it will reduce fabricating cost.
Źródło:: Journal of Machine Engineering; 2008, 8, 4; 25-31
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Effect of Laser Preheating AISI 4140 Specimens for Micro-Forging
Autorzy:: Jung, C.
Lee, M. G.
Jeon, Y.
Powiązania:: https://bibliotekanauki.pl/articles/351766.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: laser preheating
micro-forging
fatigue strength
ultrasonic fatigue test
hardness
Opis:: Many high performance and permanent service parts require suitable material characteristics-high fatigue strength is one of the most important characteristics. For this reason, surface treatment processes are essential to increase the material performance and avoid the use of costly ineffective material. There exist various surface treatment processes for various applications. Each process has advantages and disadvantages and hybridization can solve various problems. The micro-forging process delivers a controlled and uniform surface hardness, but the depth of the forged surface is limited. On the other hand, laser heat treatment can increase the hardness drastically, but the surface may become brittle, which reduces the fatigue life. Laser-assisted micro-forging is a novel hybrid process of laser heat treatment and micro-forging that has the potential to increase the forging depth and relax the stress caused by the high temperature of the forging process. This study examines the effect of laser preheating in the micro-forging of AISI 4140. The processes were varied as follows: no treatment, micro-forging only, and laser-assisted micro-forging. The fatigue strength of the specimens was examined by means of an ultrasonic fatigue tester and then compared. The microstructural changes were investigated with respect to the processes by using scanning electron microscopy. In conclusion, it was confirmed that the laser preheating auxiliary forging affects the fatigue life. It was confirmed that the fatigue life was the mostly increased in 550°C temperature laser preheating micro forging process and the temperature was identified as the most important factor.
Źródło:: Archives of Metallurgy and Materials; 2017, 62, 2B; 1209-1213
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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