• Title/Summary/Keyword: Surface Expansion

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An Experimental Study on the Bond Strength after Surface Treatment of Non-precious Metal Alloy for porcelain Crown (도재용 비금속합금의 표면처리에 따른 결합강도에 관한 실험적 연구)

  • So, Myung-Sub
    • Journal of Technologic Dentistry
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    • v.9 no.1
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    • pp.39-49
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    • 1987
  • This study done to evaluate some surface treatment methods in metal coping which can increase the bond strength between porcelain and metal. Therefore this experiment was performed according to the Mc Lean's Theory of bond strength between porcelain and strength between porcelain and metal. In the experiment the author measured respective thermal expansion coefficents in three types of metal(Tallasium, Vera Bond and Rexillium) and Vita Porcelain to get the differences in the coefficents between porcelain and metals. And using insteron testing machine, the author also performed Planar interface shear bond tests on the 45 specimens(15 specimens in oxide surface, rough surface and fine surface treatment methods respectively) to measure bond strength between metal and porcelain. The results Were as follows, 1. The differences in thermal expansion coefficients between three types of metal and Vita procelain: Talladium - $1.2\;10^{-6/0}\;C$, Vera Bond - $1.6\;10^{-6/0}\;C$, Rexillium - $1.9\;10^{-6/0}\;C$. 2. The bond strength in oxide surface on the Shear bond test was the lowest among the treatment methods. 3. There was no significant differences in treatment methods of rough surface of fine surface. 4. In the oxide surface treatment method, there were significant differences(P<0.05)between Vera bond and Rexillium, and between Talladium and Rexillium. 5. In the fine surface treatment, there was a significant difference(P<0.05)between Talladium and Rexillium.

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Analysis for the Residual Stress by Cold Expansion Method and Interference Fit (흘확장법과 억지끼워맞춤에 의한 잔류응력 해석)

  • Jang, Jae-Soon;Yang, Won-Ho;Kim, Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.8
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    • pp.1615-1622
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    • 2002
  • The purpose of this study is comparing cold expansion method with interference fit. Cold expansion method and interference fit of fastener hole is using in the aerospace industry. These treatment lead to an improvement of fatigue life to the compressive residual stresses developed on the hole surface. But Research is nothing to about difference effect of between cold expansion method and interference fit. So, this paper, it is shown that Comparing cold expansion method with interference fit using the finite element method. It is further shown that residual stress distribution according to plate thickness and clamping force.

The Finite Element Analysis for Comparision of Residual Stress at Cold Expansion Method and Interfernce Fit (홀확장법과 억지끼워맞춤의 잔류응력 비교를 위한 유한요소해석)

  • Jang, Jae-Soon;Yang, Won-Ho;Kim, Cheol;Ko, Myung-Hoon
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.419-424
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    • 2001
  • The purpose of this study is comparing cold expansion method with interference fit. Cold expansion method and interference fit of fastener hole is using in the aerospace industry. These treatment lead to an improvement of fatigue life to the compressive residual stresses developed on the hole surface. But Research is nothing to about difference effect of between cold expansion method and interference fit. So In this paper, It is shown that Comparing cold expansion method with interference fit. and It is further shown that residual stress distribution according to plate thickness.

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Optimal Design of Dual-Structured Disc of a Safety-Valve for the Specialized Pressure Vessel Considering Thermal Expansion (특수 압력요기용 안전밸브의 2중 구조로 디스크의 최적설계)

  • Kim, Chang-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.4
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    • pp.81-85
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    • 2007
  • A safety valve is used for protecting the pressure vessel and facilities by discharging the operating fluid into the valve from the accident when the pressure is over the designated value. The fluid is sulfurous acid and nitric acid. etc. in the semi-conductor assembly line. Thus the valve elements material must be acid resistance. Teflon, which is used generally as inner parts of a valve, tends to easily sticks to sliding surface by thermal expansion under high temperature. Some studies are performed to change teflon to another material and shape to have a better fluidity under the condition. The analysis of the thermal expansion is conducted by commercial FEM software to improve the problems. Boundary conditions were temperature and load in this study. From the analysis, the thermal expansion of stainless steel is verified to be lower than that of teflon under high temperature. Thus coupled teflon/stainless steel-made valve is applied to assembly line without danger due to thermal expansion.

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The Finite Element Analysis for Prediction of Residual Stresses Induced by Cold Expansion (홀확장 잔류응력 예측을 위한 유한요소해석)

  • Kim, Cheol;Yang, Won-Ho;Ko, Myung-Hoon;Heo, Sung-Pil;Hyun, Cheol-Seung
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.470-474
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    • 2000
  • Cold expansion of fastener holes is a mechanical process widely used in the aerospace industry. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses on the hole surface. The residual stress profile depends on the parameters of cold expansion, which are, expanding rate, inserting direction of mandrel, material properties etc. and the method to confirm this profile is only measurement by X-ray diffractometer. Despite its importance to aerospace industries, little attention has been devoted to the accurate modelling of the process. In this paper, Two-dimensional axisymmetric finite element simulations have been conducted for the cold expansion in an aluminium plate in order to predict the magnitude and distribution of the residual stress and plastic deformation. Maximum compressive residual stress could be increase about 7 percent using the 2-step cold expansion method.

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Detection of Urban Expansion and Surface Temperature Change using Landsat Satellite Imagery (Landsat 위성영상을 이용한 도시확장 및 지표온도 변화 탐지)

  • Song, Yeong-Sun
    • Journal of Korean Society for Geospatial Information Science
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    • v.13 no.4 s.34
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    • pp.59-65
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    • 2005
  • It is very important to detect land cover/land use change from the past and to use it for future urban plan. This paper investigated the application of Landsat satellite imagery for detecting urban growth and assessing its impact on surface temperature in the region. Land cover/land use change detection was carried out by using 30m resolution Landsat satellite images and hierarchial approach was introduced to detect more detail change on the changing area through high resolution aerial photos. Also, surface temperature according to land cover/land use was calculated from Landsat TM thermal infrared data and compared with real temperature to analyze the relationship between urban expansion and surface temperature. As a result, the urban expansion has raised surface radiant temperature in the urbanized area. The method using remote sensing data based on GIS was found to be effective in monitoring and analysing urban growth and in evaluating urbanization impact on surface temperature.

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Effect of Surface Modification of Waste Glass for Fine Aggregate on the Mechanical Properties and Alkali Silica Reaction of Mortar (잔골재용 폐유리의 표면개질이 모르타르의 역학적 특성 및 알칼리 실리카 반응에 미치는 영향)

  • Son, Min-Jae;Kim, Gyu-Yong;Lee, Sang-Kyu;Sasui, Sasui;Eu, Ha-Min;Nam, Jeong-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.23-24
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    • 2020
  • In this study, effect of surface modification of waste glass for fine aggregates on the mechanical properties and alkali silica reaction of mortar was analyzed. As a result, it was confirmed that the incorporation of waste glass fine aggregate decreases the mechanical properties of the mortar and increase the alkali silica reaction expansion. On the other hand, the surface modification of the waste glass fine aggregate is effective in improving this problem. However, unlike green and brown waste glass, it is judged that an additional experiment to determine the cause is necessary for white waste glass where alkali silica reactive expansion occurs extremely.

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Noise and Vibration Analysis of a Flat Plate by using Modal Expansion Technique (모드 확장 기법을 이용한 평판의 진동.소음 해석)

  • 김관주;이봉노
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.654-662
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    • 1998
  • To predict the radiating noise from the vibrating surface, it is required to know the velocity distribution of vibrating surface exactly as possible as it can. Although it can be obtained by finite element method, their accuracy is limited by theuncertainty of preparing input data such as material propoerties, damping, excitation, and the actual boundary conditions. Experimental values are accurate but are seldom available as many asthe data points compared to FEM mesh. Therefore, hybrid method of experiment and finite element method, called modal expansion technique, is investigated for the preparatin of accurate element method at specified frequencies and for the verification of this scheme, related experiment is performed. In high frequency range above 2000 Hz, piezo-electric material is used as an actuator.

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Electrolytic recovery of metals from the plating rinse water with fluidized bed electrode reactor (유동층전극 반응기를 이용한 폐수내의 중금속 회수)

  • Lee, Jea-Keun;Chun, Hai-Soo
    • Journal of the Korean institute of surface engineering
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    • v.17 no.1
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    • pp.1-6
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    • 1984
  • The fluidized bed electrode reactor(FBER) with conducting particles has been made use of the removal of metals from dilute electroplating rinse water. The electrolysis was carried out under the conditions of diaphragm current density with 2~28A/$dm^2$ and bed expansion with 20~50%. Recirculating batch operations have been shown that the metal concentration dropped exponentially and may be taken down to 10 ppm. And then, the current efficiency at a concentration of 10 ppm copper was 37% under the conditions of 30% bed expansion and 6 A/$dm^2$, and at concentrated electrolyte (2000ppm copper) was over 80% in the range of 8~28A/$dm^2$ and 20~50% bed expansion. One of the technical possibilities of fluidized bed electrolysis is the separation of copper and nickel from a mixed solution of copper and nickel.

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A study of Dental Casting Method (치과 주조에 관한 고찰)

  • Choi, Jea-Kyung;Nho, Hwon-Ju
    • Journal of Technologic Dentistry
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    • v.9 no.1
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    • pp.79-88
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    • 1987
  • According as the density of prosthetic by casting among the prosthetic restorations is increasing now, the definition and the bounds as to the casting, the method of making the right casting and the establishment of concepts about a minute report and so on, the establishment of the basic principles like those are unavoidable, and then the casting shrinkage must be compensated by setting expansion thermal expansion. Hygroscopic expansion in making the good casting types as we demonstrated that already asbestos lining. We confirmed the fact that the considerable concern about the surface tension and the gas inspiration? Is necessary in making better the casting.

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