Lifetime Prediction and Aging Behaviors of Nitrile Rubber Under Operating Environment of Transformer

Yi-Hua Qian,Hong-zhao Xiao,Ming-hao Nie,Yao-hong Zhao,Yunbai Luo,Shu-ling Gong 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at 70°C under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at 25°C was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

Lifetime Prediction and Aging Behaviors of Nitrile Butadiene Rubber under Operating Environment of Transformer

Qian, Yi-hua,Xiao, Hong-zhao,Nie, Ming-hao,Zhao, Yao-hong,Luo, Yun-bai,Gong, Shu-ling The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at $70^{\circ}C$ under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at $25^{\circ}C$ was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

Lifetime Prediction and Aging Behaviors of Nitrile Butadiene Rubber under Operating Environment of Transformer

Yi-hua Qian,Hong-zhao Xiao,Ming-hao Nie,Yao-hong Zhao,Yun-bai Luo,Shu-ling Gong 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at 70°C under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at 25°C was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

금속유물 강화용 아크릴수지 수명예측

곽홍인,김진국 국립중앙박물관 2009 박물관보존과학 Vol.10 No.-

금속유물 강화제로 널리 사용 중인 아크릴계 수지 ParaloidTM B-72(EMA copolymer)의 수명예측을 위한 연구이다. 수명인자로서는 온도를 고려하였으며, 수명예측을 위한 test parameter로써 색도를 선택하였다. 그 결과, 같은 농도의 도막에서 온도에 대한 노화가 주요 요인이라는 것을 알았다. 즉 환경온도 24℃에서 24시간일 때 수명은 12.0년, 20℃에서 24시간일 때 수명은 17.1년, 16℃에서 24시간일 때 수명은 24.5년으로 예측되었다. 이 실험을 평가는 Arrhenius 관계식을 이용하여 예측하였다. The purpose of this study is to determine the lifetime of acrylic resin ParaloidTM B-72(EMA copolymer), which is widely used as a coating for metallic artifacts to prevent corrosion. Lifetime factor with temperature, select ed chromaticity as the test parameter for lifetime prediction. The found result is that the temperature is the most crucial factor influencing the prediction of the lifetime of the EMA copolymer coated iron surface against corrosion. The simulation results, based on Arrhenius Equation, showed that the lifetime prediction of the EMA coated iron surface was 24.5 years at 16 , 17.1 years at 20 , and 12.0 years at 24 , respectively.

Lifetime Prediction of Silicone and Direct Ink Writing-Based Soft Sensors Under Cyclic Strain

Kyeongtaek Kim,Joonbum Bae 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.2

The softness and stretchability of soft sensors has generated much interest with respect to applying soft sensors for human activity monitoring and proprioception of soft robots. However, most of the research in this area has focused on electrical stability, despite the importance of mechanical failure, thus limiting practical application. In this study, the lifetime of silicone-based soft sensors was examined under accelerated cyclic strain conditions, to construct lifetime prediction models of crack nucleation and growth considering the failure properties of the sensor’s silicone elastomer. To establish the models, an accelerated life test was conducted, in which the lifetime was estimated according to a Weibull distribution under accelerated cyclic strain conditions. Specifically, a lifetime prediction model using the crack growth approach (CGA) was constructed by experimentally measuring the energy release rate (tearing energy) of the silicone elastomer due to crack propagation. Compared to the inverse power law-based model, the CGA-based model showed about 90% improvement in lifetime prediction accuracy in the strain ranges from 150 to 270% with root mean square error 456 and 4592 cycles, respectively, thus indicating that tearing energy is an important parameter for sensor lifetime prediction. The proposed model is expected to be useful for predicting the lifetime of soft sensors under various strain operating conditions.

Personalized Battery Lifetime Prediction for Mobile Devices based on Usage Patterns

Kang, Joon-Myung,Seo, Sin-Seok,Hong, James Won-Ki Korean Institute of Information Scientists and Eng 2011 Journal of Computing Science and Engineering Vol.5 No.4

Nowadays mobile devices are used for various applications such as making voice/video calls, browsing the Internet, listening to music etc. The average battery consumption of each of these activities and the length of time a user spends on each one determines the battery lifetime of a mobile device. Previous methods have provided predictions of battery lifetime using a static battery consumption rate that does not consider user characteristics. This paper proposes an approach to predict a mobile device's available battery lifetime based on usage patterns. Because every user has a different pattern of voice calls, data communication, and video call usage, we can use such usage patterns for personalized prediction of battery lifetime. Firstly, we define one or more states that affect battery consumption. Then, we record time-series log data related to battery consumption and the use time of each state. We calculate the average battery consumption rate for each state and determine the usage pattern based on the time-series data. Finally, we predict the available battery time based on the average battery consumption rate for each state and the usage pattern. We also present the experimental trials used to validate our approach in the real world.

Personalized Battery Lifetime Prediction for Mobile Devices based on Usage Patterns

Joon-Myung Kang,Sin-seok Seo,James Won-Ki Hong 한국정보과학회 2011 Journal of Computing Science and Engineering Vol.5 No.4

Nowadays mobile devices are used for various applications such as making voice/video calls, browsing the Internet, listening to music etc. The average battery consumption of each of these activities and the length of time a user spends on each one determines the battery lifetime of a mobile device. Previous methods have provided predictions of battery lifetime using a static battery consumption rate that does not consider user characteristics. This paper proposes an approach to predict a mobile device"s available battery lifetime based on usage patterns. Because every user has a different pattern of voice calls, data communication, and video call usage, we can use such usage patterns for personalized prediction of battery lifetime. Firstly, we define one or more states that affect battery consumption. Then, we record time-series log data related to battery consumption and the use time of each state. We calculate the average battery consumption rate for each state and determine the usage pattern based on the time-series data. Finally, we predict the available battery time based on the average battery consumption rate for each state and the usage pattern. We also present the experimental trials used to validate our approach in the real world.

자동차 내장부품용 천연섬유/폴리프로필렌 복합재료의 가속 열화에 관한 연구

이평찬(Pyoung-Chan Lee),엄찬혁(Chanhyeok Um),정선경(Sun Kyoung Jeoung),고윤기(Youn Ki Ko),하진욱(Jin Uk Ha),이주엽(Ju-Yub Lee),이재용(Jae Yong Lee),김광섭(Kwang Sup Kim),김동혁(Dong Hyeok Kim) 한국고분자학회 2021 폴리머 Vol.45 No.6

본 연구에서는 자동차 내장 도어 트림용 천연섬유/폴리프로필렌(NFPP) 복합재료의 수명 예측에 관하여 연구하였다. 가속수명예측은 자동차 부품의 신뢰성을 확인하는 핵심 기술이다. 가속 열화 시험은 사용 온도보다 높은 온도인 110, 130, 및 150 ℃에서 수행하였다. 노화 온도에 따른 열분석 결과, 열분해 온도는 낮아지고 열분해 속도는 빨라지는 것을 확인하였다. 노화 온도 및 시간에 따른 인장강도는 가속 수명 예측 모델 분석에 활용하였다. NFPP 복합재료의 수명 예측은 아레니우스-와이블 분포 모델을 활용하여 예측하였다. NFPP 복합재료의 B₁ 수명 예측 결과 상온(23 ℃)에서 684백만 시간, 80 ℃에서 39.2천 시간을 나타내었다. In this study, lifetime prediction of natural fiber/polypropylene (NFPP) composites for automotive door trim was investigated using an accelerated aging test. Accelerated lifetime prediction was the key technology to assure the reliability of automotive components. The accelerated thermal aging test was performed at the temperature of 110, 130, and 150 ℃. As a result of thermal analysis according to the thermal aging temperature, it was confirmed that the thermal decomposition temperature was lowered and the thermal decomposition rate was increased. The measured tensile strengths as a function of thermal aging temperature were used as accelerated lifetime prediction data for the analysis of the NFPP composites lifetime. The lifetime of the NFPP composite was estimated using the Arrhenius-Weibull distribution model. The estimated results exhibited that the B1 lifetime of the NFPP composites was 684 million hours at room temperature (23 ℃) and 39.2 thousand hours at 80 ℃, respectively.

매설 환경에 따른 파형강 구조물의 부식 특성 연구

박연수 ( Park Yeon-soo ),김병하 ( Kim Byoung-ha ),한상호 ( Han Sang-ho ),박선준 ( Park Sun-joon ),서병철 ( Suh Byoung-chal ) 한국구조물진단유지관리공학회 2003 한국구조물진단유지관리공학회 논문집 Vol.7 No.1

In this research, multiple corrosion factors of buried environments were measured in order to establish a formula for the corrosion character of corrugated steel structures in domestic environments. By substituting corrosion factors for each predicting formula, the durable lifetime was measured, and the measured lifetime was compared with the estimated lifetime by applying existing thickness-measuring techniques. A new usage standard was proposed with these results, in order to create the conclusion below. There are known differences in the soil factors used as variables in estimating the duration caused by the seasonal effects of rainfall and temperature. Comparing the durable lifetime estimated by each predicting formula, the findings show that the California technique is conservative. This study demonstrates that the error range of the AISI technique, which is mostly used as a duration technique, is a very narrow predicting technique as compared with many other countries. Considering that there is on average, a 13% error margin in this study, a proposed safety factor of 0.87 could be used to more accurately predict the duration. The laying time in the California technique is not longer than the whole durability, and as a result, this error margin exists. It is concluded that this study on the open area has been overdue. Based on these findings, it's proposed that this error margin should be applied to the domestic environment through periodic observation, in order to establish the predicting techniques of durable lifetime.

전동차용 세브론 고무스프링 특성 및 사용수명 평가

우창수(Woo, Chang-Su),박현성(Park, Hyun Sung),강문채(Kang, Mun-Chae) 한국도시철도학회 2013 한국도시철도학회논문집 Vol.1 No.2

전동차량의 1차 현가장치로 사용되는 세브론 고무스프링의 특성과 사용수명을 예측하고 평가하는 기술은 안전성과 신뢰성을 확보하기 위해 매우 중요하다 하겠다. 변형률 에너지함수로 정의되는 고무소재의 비선형 물성은 세브론 고무스프링의 해석과 설계에 중요한 변수로 단축인장, 등 이축인장 및 순수전단시험을 통해 결정하였으며, 전산해석을 통해 세브론 고무스프링의 특성을 예측하고 평가하였다. 또한, 유한요소 해석과 피로시험을 통해 취약부위에서의 최대 그린-라그랑지 변형률을 이용하여 가황고무 소재의 사용수명 예측방법을 제안하였다. 제안된 방법에 의해 예측된 세브론 고무스프링의 사용수명은 피로시험을 통해 얻어진 수명과 잘 일치함을 알 수 있었다. Chevron rubber springs is used in primary suspension system for electric locomotives. Characteristics and useful lifetime prediction and evaluation of chevron rubber spring were very important in design procedure to assure the safety and reliability. Non-linear properties of rubber material which are described as strain energy function was important parameter to design and analysis of chevron rubber spring. These are determined by mechanical tests which are uni-axial tension, equi-biaxial tension and pure shear test. The computer simulation was execute to predict and evaluate the characteristics for chevron rubber spring. Also, Useful lifetime prediction methodology of vulcanized natural rubber was proposed by incorporating the finite element analysis and fatigue damage parameter of maximum Green-Lagrange strains appearing at the critical location determined from fatigue test. Predicted useful lifetime of the chevron rubber spring showed a fairly good agreement with the experimental useful lifetime.