• 한국신뢰성학회지:신뢰성응용연구
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• 제12권2호
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• pp.67-78
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• 2012

An electric double-layer capacitor(EDLC) is an electrochemical capacitor with relatively high energy density, typically hundreds of times greater than conventional electrolytic capacitors. EDLCs are widely used for energy storage rather than as general-purpose circuit components. They have a variety of commercial applications, notably in energy smoothing and momentary-load devices, and energy-storage and kinetic energy recovery system devices used in vehicles, etc. This paper presents an accelerated degradation test of an EDLC with rated voltage 2.7V, capacitance 100F, and usage temperature $-40^{\circ}C{\sim}65^{\circ}C$. The EDLCs are tested at $50^{\circ}C$, $60^{\circ}C$, and $70^{\circ}C$, respectively for 1,750hours, and their capacitances are measured at predetermined times by constant current discharge method. The failure times are predicted from their capacitance deterioration patterns, where the failure is defined as 30% capacitance decrease from the initial one. It is assumed that the lifetime distribution of EDLC follows Weibull and Arrhenius life-stress relationship holds. The life-stress relationship, acceleration factor, and $B_{10}$ life at design condition are estimated by analyzing the accelerated life test data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1945-1947
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• 2005

This study considers find out best accelerated life testing and lifetime prediction of electrolytic capacitors. We proved about relation between failure and deterioration mechanism from last thesis. Beside we performed test that temperature and voltage press higher than allowance specification. Failure distribution acquired from those test. And wiebull function and Minitab program applied to accelerated constant and lifetime by means of calculation. At the result, goodness of fit affect to weibull function and acceleration factor therefore fitting is important factor in reliability testing.

• 한국기계가공학회지
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• 제21권6호
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• pp.67-73
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• 2022

Industrial inverters are used in a variety of fields for electric power supply. They may be exposed to vibration and heat once they are installed. This study focused on a framework of accelerated life testing of an industrial inverter considering fatigue damage as the primary source of deterioration. Instead of analyzing detailed failure mechanisms and the product's vulnerability to them, the potential of fatigue failure is considered using the fatigue damage spectrum calculated from the environmental vibration signals. The acceleration and temperature data were gathered using field measurement and spectral analysis was conducted to calculate the vibration signal's power spectral density (PSD). The fatigue damage spectrum is then calculated from the input PSD data and is used to design an accelerated fatigue life testing. The PSD for the shaker table test is derived that has the equivalent fatigue damage to the original input signal. The tests were performed considering the combined effect of random vibration and elevated temperature, and the product passed all the planned tests. It was successfully demonstrated that the inverter used in this study could survive environmental vibration up to its guarantee period. The fatigue damage spectrum can effectively be used to design accelerated fatigue life testing.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.384-390
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• 2011

To evaluate the condition of stator winding insulation in generators that have been operated for a long period of time, diagnostic tests were performed on the stator bars of a 500 MW, 22 kV generator under accelerated thermal and electrical aging procedures. The tests included measurements of AC current (${\Delta}I$), dissipation factor ($tan{\delta}$), partial discharge (PD) magnitude, and capacitance (C). In addition, the AC current test was performed on the stator winding of a 350 MW, 24 kV generator under operation to confirm insulation deterioration. The values of ${\Delta}I$, ${\Delta}tan{\delta}$, and PD magnitude in one stator bar indicated serious insulation deterioration. In another stator bar, the ${\Delta}I$ measurements showed that the insulation was in good condition, whereas the values of ${\Delta}tan{\delta}$ and PD magnitude indicated an incipient stage of insulation deterioration. Measurements of ${\Delta}I$ and PD magnitude in all three phases (A, B, C) of the remaining generator stator windings showed that they were in good condition, although the ${\Delta}tan{\delta}$ measurements suggested that the condition of the insulation should be monitored carefully. Overall analysis of the results suggested that the generator stator windings were in good condition. The patterns of PD magnitude in all three phases (A, B, C) were attributed to internal discharge.

• 한국작물학회지
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• 제37권2호
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• pp.171-177
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• 1992

실험실에서 실시한 검정으로 Lotus와 Red clover 종자의 포장출현율 예측에 효과적인 검정방법을 구명하기 위하여 상이한 조건에서 재배된 종자를 퇴화조절검정법, 인위노화검정법과 전기전도도 검정방법으로 검정하였다. 이들을 포장출현율과의 관련성을 구명 하였던 바 1. Lotus와 Red clover의 포장출현율을 예측할 때 퇴화조절검정에서는 (equation omitted)=12.786＋0.65X($R^2$=0.687), 인위노화검정에서는 (equation omitted)=25.989＋0.39X($R^2$=0.260), 전기전도도검정에서는 (equation omitted)=141.932-0.86X($R^2$=0.238)으로써 예측할 수 있었으며 2. 이들 세가지 검정에서의 결과와 포장출현율과는 다음과 같은 다중회귀방정식으로 나타낼수 있었다. (equation omitted)=-198.16＋2.3493X$_1$-1.5564X$_2$＋1.981X$_3$($R^2$=0.916) 여기서, X$_1$, 퇴화조절검정법 ; X$_2$, 인위노화검정법 ; X$_3$, 전기전도도검정임. 3. 이러한 결과는 단일검정법으로 실내에서 포장출현율을 예측하려면 인위노화검정법이나 전기전도검정법 보다도 퇴화조절검정법이 비교적 효율이 높았으며, 이들 세가지 방법을 병용할 때에는 단일검정법보다도 효율을 증가시킬수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.221-224
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• 2004

Several factors of concrete durability decline factor are acted as complex deterioration and is happened not that happen by simplicity deterioration. Specially, in case of sea construction, as complex salt damage, carbonation and freezing & thawing, concrete surface and pore structure is deteriorated. Therefore, analyzing concrete carbonation and pore structure after freezing and thawing test by fresh water and sea water in this research, we wish to study about acceleration of decline of durability and complex deterioration by concrete surface deterioration in sea environment.

• 콘크리트학회논문집
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• 제13권4호
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• pp.397-405
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• 2001

해안에 근접한 콘크리트 구조물이 동결음해 작용을 받을 경우, 내륙 콘크리트에 비해 내구성능 저하가 촉진된다. 그리고 최근 동절기에 차량의 안전 주행을 위해 도로 및 교량에 염화칼슘 등의 제설제의 산포량이 현격히 증가하고 있으며 이로 인해 내륙 콘크리트 구조물도 해안 콘크리트 구조물과 마찬가지로 동결융해와 염해의 복합작용에 의한 내구성능 저하가 염려된다. 미국, 일본 및 유럽 등에서는 제설제가 콘크리트에 미치는 영향에 대해 연구가 활발히 진행되고 있다. 그리고 제설제가 콘크리트에 미치는 영향을 검토하는 시험방법이 제정되었다. 그러나 우리 나라에서는 동결융해와 염해에 대한 복합 내구성능 저하시험방법은 제정되어 있지 않으며 또한 이에 대한 연구가 이루지지 않고 있다. 따라서 본 연구에서는 동결융해와 염해의 복합작용을 받는 콘크리트의 내구성능 저하를 평가하는 방법을 검토하기 위해 복합 내구성능 저하 실험을 실시하였다. 복합시험에서 시멘트 종류, 강도, 공기량 등이 스케링에 미치는 영향을 검토하였다. 그 결과, 염화물 존재 하에서 동결융해 작용을 받는 경우, 콘크리트의 스케링 손실이 촉진된다. 또한 스케링에 대한 저항성은 사용 시멘트 종류, 콘크리트의 강도, 공기량의 영향을 크게 받는다.

• 콘크리트학회논문집
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• 제11권6호
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• pp.129-135
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• 1999

Reinforced concrete structures are constructed under the basic assumption of perfect bonding between steel and concrete. The corrosion of steel in the reinforced concrete beams results in the excessive cracks and gradual deterioration of concrete. This paper are concerned about the slip characteristics of reinforced concrete between steel and concrete. The accelerated test by external power supply was conducted with the three corrosion rates in the laboratory. As a result, it was obtained as follows: (1) the yield strength of steel was reduced according to corrosion states. (2) the equivalent steel area should be considered for detailed analysis. (3) According to the use of corroded steel or not, slip amounts between concrete and steel in test beams increased as the corrosion rate increased. These results can be explained from the bond loss between concrete and steel in test beams.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.456-458
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• 2022

국제해사기구의 환경규제로 조선소에서는 선박의 효율향상을 위한 다양한 연구를 추진하고 있으며, 선박의 무게절감을 위한 노력이 진행 중이다. 최근, CNT소재를 포함하는 복합소재는 일반 철판 소재 대비 40% 이상 무게절감이 가능한 장점이 있어, 선박의 클램프나 도어스킨으로 대체사용이 가능한 장점이 있다. 이에, 본 연구에서는 CNT소재를 포함하는 복합소재의 수명예측을 위해, 가속열화시험 방법과 머신러닝 기법을 이용한 수명예측을 통해 결과를 비교하였다. 가속열화시험은 아레니우스 모델식을 이용하였고, 머신러닝 기법은 회기분석 알고리즘을 이용하여 수명을 예측하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.203-206
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• 2005

The purpose of this study is to develop the evaluation method of repair performance for the repair method of reinforced concrete structures deteriorated due to combined deterioration, its results are summarized as the follows. After investigating and analyzing the experimental data of this study and existing research, it is proposed the evaluation method on the repair performance for the repair method of reinforced concrete structures using evaluation method of reinforcing corrosion by combined deterioration accelerated test.