• Title/Summary/Keyword: 아레니우스식

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Fracture Mechanics Applied to Fatigue Crack Growth Behavior at Elevated Temperatures (고온 피로균열 성장거동에 관한 파괴역학의 응용에 관한 연구)

  • 서창민;김영호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.6
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    • pp.1552-1560
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    • 1990
  • A general form of the mathematical function in the fatigue crack growth rate law for CT specimens was determined by means of the dimensional analysis at elevated temperatures. The experimental results can be rigorously described by the combination of rate theory and fracture mechanics. The rate theory approach extends the scope of fracture mechanics through the consideration of the temperature. The fatigue crack growth rates are represented by the Arrhenius type equation. This equation explains fairly well the experimental data for Cr-Mo-V rotor steel and A517-F steel in the comparatively wide temperature regions as affected with the temperature and the stress intensity factor range interaction.

Accelerated Life Prediction of Ethylene-Propylene Diene Monomer Rubber Subjected to Combined Degradation (복합노화를 받는 EPDM 고무의 가속수명예측)

  • Han, Seung Wook;Kwak, Seung Bum;Choi, Nak Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.5
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    • pp.505-511
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    • 2014
  • The EPDM(ethylene-propylene diene monomer) rubbers used for manufacturing engine radiator hoses can be degraded by locally generated electrical stress in addition to thermal and mechanical stresses. This study presents an accelerated life prediction of the EPDM rubber under electrochemical stresses using the Arrhenius formula under various aging temperatures($60^{\circ}C$, $80^{\circ}C$, and $100^{\circ}C$). The modified life prediction formula considers the relationship between the gradient($E_a/R$) and the Arrhenius constant(C). The effects of tensile strain(5%, 10%) on the life of these rubbers were investigated. The aging temperature influences EPDM rubber life, and tensile strain was predicted. It was confirmed that the modified life prediction was within the data deviation level of the test.

A three-dimensional patent evaluation model that considers the factors for calculating the internal and external value of a patent: Arrhenius chemical reaction kinetics-based patent lifespan prediction (특허의 내적.외적 가치산정요인을 고려한 입체적 특허평가모델: 아레니우스 화학반응속도론 기반의 특허수명예측)

  • Choi, Yong Muk;LEE, JAEWON;Cho, Daemyeong
    • Journal of Digital Convergence
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    • v.19 no.6
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    • pp.113-132
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    • 2021
  • This study is a new evaluation using the Arrhenius equation, which is known as the chemical reaction rate estimation equation, to evaluate the intrinsic and extrinsic value elements of patents as a model. The performance of the evaluation model was superior to the SVM, Logistic reg. and ANN models that were used as patent evaluation models in prior studies. In addition, there was a strong correlation between the predicted lifespan of the patent and the actual lifespan of the patent. These evaluation models may be used for evaluation purposes only, or if an evaluation is required, including a commercialization entity or technical characteristics.

Prediction of Useful Life by Heat Aging of Motor Fan Isolating Rubber (모터팬 방진고무부품의 노화수명 예측)

  • Kim, W.S.;Woo, C.S.;Cho, S.J.;Kim, W.D.
    • Elastomers and Composites
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    • v.37 no.2
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    • pp.107-114
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    • 2002
  • This paper discusses the accelerated heat aging tests were carried out to predict the useful life of EPDM isolating rubber components of ventilation fan motor for clean room. 20% compression set results changes as the threshold are used for assessment of the useful life and the time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. The useful life at variable temperatures and activation energy are obtained from the Arrhenius relationship. An accelerated test program to assess useful life can be represented an appreciable investment in time was designed. We also considered the effect of antioxidant agents.

Accelerated Life Test for 1.25Gbps Transceiver (광통신용 1.25Gbps Transceiver 가속수명시험)

  • Yun, Gwang-Su;Yu, Chong-Hee;Heo, Young-Soon
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1391-1393
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    • 2008
  • In this paper, the long-term reliability for 1.25G transceiver in use of high speed optical access network is investigated. High temperature storage tests and accelerated life tests are used to long-term reliability. Accelerated aging test have been during 3,000 hour of the three accelerated aging conditions by caused high temperature stress. Mean life is assumed to follow the Arrhenius relationship and analysis from the failure data obtained in the accelerated aging conditions.

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A Viscoelastic Study of Glass Transition and Degradation Processes of Phenolic Resin/Carbon Fiber Composites (페놀수지/탄소섬유 열경화성 복합재료의 유리전이와 고온 분해과정에서 관찰되는 점탄성 특성 연구)

  • ;J. C. Seferis
    • The Korean Journal of Rheology
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    • v.11 no.1
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    • pp.9-17
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    • 1999
  • Viscoelastic characteristics of cured phenolic resin/carbon fiber composite materials were investigated through glass transition and degradation reaction processes in the high temperature region up to $400^{\circ}C$. A typical glass transition of the cross-linked thermoset polymer was followed by irreversible degradation reactions, which were exhibited by the increasing storage modulus and loss modulus peak. A degradation master curve was constructed by using the vertical and horizontal shift factors, both of which complied well with the Arrhenius equation in light of the kinetic expression of degradation rate constants. Using an analogy to the Havriliak-Negami equation in dielectric relaxation phenomena, a viscoelastic modeling methodology was developed to characterize the frequency- and temperature-dependent complex moduli of the degrading thermoset polymer composite systems. The temperature-dependent relaxation time of the degrading composites was determined in a continuous fashion and showed a minimum relaxation time between the glass transition and degradation reaction regions. The capability of the developed modeling methodology was demonstrated by describing the complex behavior of the viscoelastic complex moduli of reacting phenolic resin composite systems.

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Rheological Properties of Gelatinized Chestnut Starch Solution (밤전분 호화액의 유동특성)

  • Park, Young-Hee;Kim, Sung-Kon;Lee, Shin-Young;Kim, Ju-Bong
    • Korean Journal of Food Science and Technology
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    • v.16 no.3
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    • pp.314-318
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    • 1984
  • Rheological properties of gelatinized chestnut starch solution were investigated with a narrow gap rotational viscometer. The starch solutions at 1.2-1.8% concentration showed pseudoplastic behaviour with yield stress. At higher concentrations (1.65 and 1.8%), the starch solution showed more pseudoplastic tendency and time-dependent characteristics. Values of yield stress were small and independent of concentrations 1.2, 1.35 and 1.5%. Significant increase of yield stress was observed at 1.65% concentration. Consistency index was exponentially dependent on concentration and temperature. The activation energy for 1.65% starch solution was about 5 Kcal/g.mol.

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A Study for Aging Factor of Bulletproof Helmet : High Temperature Treatment (방탄헬멧의 노화인자에 관한 연구 : 고온 환경 처리를 중심으로)

  • Park, Ho Yun;Gu, Seung Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.332-339
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    • 2020
  • This study was a prior study to establish the shelf life of bulletproof helmets, considered the aging factor of bulletproof helmets. To estimate the aging factor of bulletproof helmets, we established a hypothesis that the 'temperature' factor would have the greatest impact on the shelf life of the bulletproof helmet, considering the environmental treatment of the American army's bulletproof helmet's materials. To verify the hypothesis, high temperature acceleration environmental treatment of bulletproof helmets was performed, and the Arrhenius formula was applied to calculate the shelf life. The study result confirmed the negative correlation between bulletproof performance and high temperature, and the influence of temperature as an aging factor was not significant by deriving life by using the Arrhenius model. The limitation of this study is that we couldn't obtain enough samples due to the specificity (miliary supplies) of the test subjects. However, given that the life-related research on bulletproof helmets has not been carried out, this research has great implications and could be used as a reference for improving the Korean Army's bulletproof helmet specifications.

Rheological Properties of Naked Barley Starches (쌀보리 전분 호화액의 리올로지 특성)

  • Park, Yang-Kyun;Lho, Il-Hwan;Kim, Kwan;Kim, Sung-Kon;Lee, Shin-Young
    • Korean Journal of Food Science and Technology
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    • v.18 no.4
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    • pp.278-282
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    • 1986
  • Rheological properties of naked barley (Songhak and Youngsan) starches were compared. The gelatinized starches at $3{\sim}9%$ concentration showed a Bingham pseudoplastic behavior. Songhak starch had higher values of consistency index and yield stress than those of Youngsan starch. The dependence of consistency index on concentration was mere pronounced in Songhak starch. Consistency index of both starches was exponentially dependent on concentration, but the slopes at $3{\sim}5%\;and\;5{\sim}9%$ starch concentration were different. The activation energies of 7% for Songhak and Youngsan starches were 4.10 and 3.71 Kcal/mole, respectively.

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