• Title/Summary/Keyword: Accelerated Life Test

Search Result 541, Processing Time 0.03 seconds

A Study on the Life-time Prediction for the Rubber O-ring applied to decoy through the Accelerated Life Test (기만기 적용 고무 O-ring의 온도에 따른 가속수명시험을 통한 수명예측에 관한 연구)

  • Jo, Hee-Jin;Kim, Minwoo;Gwak, Hyerim
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.10
    • /
    • pp.182-188
    • /
    • 2016
  • A decoy is a weapon system that can protect vessels from an enemy's torpedo. Thus, the decoy should be able to operate in the field without any failure. Because the decoy can be inoperable once its sealing is broken and water permeates inside the system, the hermetic sealing capability considering the operational environment is mandatory. To be hermetically sealed, a rubber-type O-ring is generally used in a decoy system. The sealed performance of rubber-type products, however, tends to age and deteriorate with time. Therefore, the O-ring needs to be maintained or changed periodically. This paper proposes a method to estimate the proper maintenance period using the hardness and elongation percentage, which represents the performance of the O-ring product and test data from Accelerated Life Test (ALT) of the product. The O-ring used in this paper is a NBR type, and the temperature was chosen to be the main accelerating factor as referenced in many studies. The criteria for the failure of the O-ring was set for the product to be 50% degraded compared to the initial performance. In addition, the Korean standard KS M 6518 was adopted and referenced for the preparation of test samples and the calculation of estimates. The O-ring's predicted life was simulated by analyzing the test results from a computer program, and the optimized maintenance period for the product was determined.

Development of Accelerated Life Test Method for Constant Electrical Potential Electrolysis Gas Sensor (정전위 전해식 가스센서의 가속수명시험법 개발)

  • Yang, Il Young;Kang, Jun Gu;Yu, Sang Woo;Oh, Geun Tae;Na, Yoon Gyoon
    • Journal of Applied Reliability
    • /
    • v.16 no.3
    • /
    • pp.180-191
    • /
    • 2016
  • Purpose: The purpose of this study was to develop the accelerated life test method for Constant Electrical Potential Electrolysis gas sensor (CEPE gas sensor). Methods: The parts and modules of CEPE gas sensor were analyzed by using Reliability Block Diagram (RBD). Failure Mode and Effect Analysis (FMEA) and Quality Function Deployment (QFD) methods were performed for each part to determine the most affecting stress factor in its life cycle. The long term testing was conducted at three different dry heat levels and the acceleration factor was developed by using Arrhenius relationship. Conclusion: The acceleration factor for CEPE gas sensor was developed by using FMEA, QFD, and statistical analysis for its failure data. Also qualification tests were designed to meet the target life.

Design of accelerated life test on temperature stress of piezoelectric sensor for monitoring high-level nuclear waste repository (고준위방사성폐기물 처분장 모니터링용 피에조센서의 온도 스트레스에 관한 가속수명시험 설계)

  • Hwang, Hyun-Joong;Park, Changhee;Hong, Chang-Ho;Kim, Jin-Seop;Cho, Gye-Chun
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.24 no.6
    • /
    • pp.451-464
    • /
    • 2022
  • The high-level nuclear waste repository is a deep geological disposal system exposed to complex environmental conditions such as high temperature, radiation, and ground-water due to handling spent nuclear fuel. Continuous exposure can lead to cracking and deterioration of the structure over time. On the other hand, the high-level nuclear waste repository requires an ultra-long life expectancy. Thus long-term structural health monitoring is essential. Various sensors such as an accelerometer, earth pressure gauge, and displacement meter can be used to monitor the health of a structure, and a piezoelectric sensor is generally used. Therefore, it is necessary to develop a highly durable sensor based on the durability assessment of the piezoelectric sensor. This study designed an accelerated life test for durability assessment and life prediction of the piezoelectric sensor. Based on the literature review, the number of accelerated stress levels for a single stress factor, and the number of samples for each level were selected. The failure mode and mechanism of the piezoelectric sensor that can occur in the environmental conditions of the high-level waste repository were analyzed. In addition, two methods were proposed to investigate the maximum harsh condition for the temperature stress factor. The reliable operating limit of the piezoelectric sensor was derived, and a reasonable accelerated stress level was set for the accelerated life test. The suggested methods contain economical and practical ideas and can be widely used in designing accelerated life tests of piezoelectric sensors.

Failure Analysis and Accelerated Life Test of MoxW1-xSi2 Haters Fabricated by SHS process (SHS 공정으로 제조된 MoxW1-xSi2 발열체의 가속수명시험과 고장분석)

  • Lee, Dong-Won;Lee, Sang-Hun;Kim, Yong-Nam;Lee, Heesoo;Lee, Sung-Chul;Koo, Sang-Mo;Oh, Jong-Min
    • Journal of IKEEE
    • /
    • v.21 no.3
    • /
    • pp.252-255
    • /
    • 2017
  • $Mo_xW_{1-x}Si_2$ heaters were fabricated by self-propagating high-temperature synthesis (SHS) process and post sintering process. To validate the reliability of the $Mo_xW_{1-x}Si_2$ heaters, the accelerated life test (ALT) was conducted, and then lifetime to $Mo_xW_{1-x}Si_2$ heaters was estimated by using Minitab programs. Also, the failure analysis of $Mo_xW_{1-x}Si_2$ heaters after ALT was performed through electrical and structural properties. As the results, it was confirmed that the dominant failure mode of $Mo_xW_{1-x}Si_2$ heaters is the crack formation in heaters and the delamination of protective $SiO_2$ layers.

Accelerated Test Design for Crankshaft Reliability Estimation

  • Jung, D.H.;Pyun, Y.S.;Gafurov, A.;Chung, W.S.
    • International Journal of Reliability and Applications
    • /
    • v.10 no.2
    • /
    • pp.109-118
    • /
    • 2009
  • Crankshaft, the core element of the engine of a vehicle, transforms the translational motion generated by combustion to rotational motion. Its failure will cause serious damage to the engine so its reliability verification must be performed. In this study, the S-N data of the bending and torsion fatigue limits of a crankshaft are derived. To evaluate the reliability of the crankshaft, reliability verification and analysis are performed. For the purpose of further evaluation, the bending and torsion tests of the original crankshaft are carried out, and failure mode analysis is made. The appropriate number of samples, the applied load, and the test time are computed. On the basis of the test results, Weibull analysis for the shape and scale parameters of the crankshaft is estimated. Likewise, the $B_{10}$ life under 50% of the confidence level and the MTTF are exactly calculated, and the groundwork for improving the reliability of the crankshaft is laid.

  • PDF

Useful lifetime prediction of rail-pad by using the accelerated heat aging test (가속 열노화시험을 통한 레일패드 사용수명예측)

  • Woo, Chang-Su;Park, Hyun-Sung;Choi, Byung-Ik;Yang, Sin-Chu;Jang, Sung-Yep;Kim, Eun
    • Proceedings of the KSR Conference
    • /
    • 2009.05a
    • /
    • pp.1010-1015
    • /
    • 2009
  • Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

  • PDF

A Bulk Sampling Plan for Reliability Assurance (벌크재료의 신뢰성보증을 위한 샘플링검사 방식)

  • Kim, Dong-Chul;Kim, Jong-Gurl
    • Journal of the Korea Safety Management & Science
    • /
    • v.9 no.2
    • /
    • pp.123-134
    • /
    • 2007
  • This paper focuses on the in-house reliability assurance plan for the bulk materials of each company. The reliability assurance needs in essence a long time and high cost for testing the materials. In order to reduce the time and cost, accelerated life test is adopted. The bulk sampling technique was used for acceptance. Design parameters might be total sample size(segments and increments}, stress level and so on. We focus on deciding the sample size by minimizing the asymptotic variance of test statistics as well as satisfying the consumer's risk. In bulk sampling, we also induce the sample size by adapting the normal life time distribution model when the variable of the lognormal life time distribution is transformed and adapted to the model. In addition, the sample size for both the segments and increments can be induced by minimizing the asymptotic variance of test statistics of the segments and increments with consumer's risk met. We can assure the reliability of the mean life and B100p life time of the bulk materials by using the calculated minimum sample size.

Accelerated Life Prediction of CPB(cold-pad-batch) Padder Roll Rubber to Chemical Degradation (CPB(Cold-Pad-Batch) 염색 패더롤 고무에서 화학적 노화로 인한 가속 수명예측)

  • Lim, Jee Young;Nam, Chang Woo;Lee, Woosung
    • Textile Coloration and Finishing
    • /
    • v.29 no.3
    • /
    • pp.155-161
    • /
    • 2017
  • In CPB(Cold-Pad-Batch) dyeing, the rubber of the padder roll is influenced by the heat, chemical and mechanical influences and thus aging of the padder roll rubber occurs. This study presents an accelerated thermal aging test of the CPB padder roll rubber with strong alkali conditions. Using Arrhenius formula of the various property values for the various aging temperatures($80^{\circ}C$, $90^{\circ}C$, $100^{\circ}C$) of the padder roll, the accelerated life predictions could be calculated. The threshold value of the property was set at different values. The hardness was set at the point where 5% degradation occurs based on the actual use conditions, and the tensile strength was set at the point where 50% degradation occurs based on the general life prediction standards. From the results of the different physical properties at differing temperatures, the Arrhenius plot could be obtained. Through the usage of the Arrhenius Equation, significant duration expectation could be predicted, and the chemical aging behavior of the CPB padder roll could be found at the arbitrary and actual temperatures.

Properties of Electrical Performance on Stator Coil of Traction Motor by Accelerated lest using Transient Surge (과도서지를 이용한 가속열화 시험법에 따른 견인전동기 고정자 코일의 전기적 특성 변화)

  • 박현준;장동욱;이길헌;최종선;김저우
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.16 no.9
    • /
    • pp.783-789
    • /
    • 2003
  • The winding problems of traction motor are the major determinant of motor's life. The root cause of winding failure is gradual deterioration of the insulation due to thermal, electrical, mechanical and environmental stresses. The aging of the insulation reduces the electrical and mechanical strength of the insulation. At same point, a voltage surge or mechanical shock from a traction motor start will fracture or break down the insulation. To achieve the expected life usually requires extensive laboratory evaluation of the insulation systems and the use of accelerated aging tests. There are several nondestructive test available for checking, the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of dielectric loss(tan$\sigma$), capacitance and partial discharge. The method of diagnosis is able to analyze the insulation condition and evaluate the life of the traction motor.

Optimal Bayesian design for discrimination of acceleration models in the exponential distribution

  • Park, Choon-Il
    • Journal of the Korean Mathematical Society
    • /
    • v.31 no.4
    • /
    • pp.709-715
    • /
    • 1994
  • The aim of of the study is a powerful test for the discrimination and therefore an optimal desin for that purpose. This problem is studied by Chernoff ([5]) and used in Chernoff ([6]) for accelerated life tests using the exponential distribution for life times. The approach used here is similar to that suggested by Lauter ([10]) and used in Chaloner ([3]) and Chaloner and Larntz ([4]) where it is motivated using Bayesian arguments. The approach taken in this paper the loss function $L(\cdot)$ evaluating a test procedure and a design d.

  • PDF