• Title/Summary/Keyword: field failure data

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Material Properties of Arctic Sea Ice during 2010 Arctic Voyage of Icebreaking Research Vessel ARAON: Part 2 - Compressive Strength, Flexural Strength, and Crystal Structures (쇄빙연구선 ARAON호를 이용한 북극해 해빙의 재료특성 (2) - 해빙의 압축강도, 굽힘강도 및 결정구조 -)

  • Kim, Dae-Hwan;Park, Young-Jin;Choi, Kyung-Sik
    • Journal of Ocean Engineering and Technology
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    • v.26 no.1
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    • pp.1-8
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    • 2012
  • To correctly estimate ice load and ice resistance for a ship's hull, it is essential to understand the material properties of sea ice during ice field trials and to use the proper experimental procedure for gathering ice strength data. The first Korean-made icebreaking research vessel (IBRV), ARAON, had her second sea ice trial in the Arctic Ocean during July and August of 2010. This paper describes the test procedures used to properly obtain sea ice strength data, which provides the basic information on the ship's performance in an ice-covered sea and can be used to estimate the correct ice load and ice resistance on the IBRV ARAON. The data gathered from three sea ice field trials during the Arctic voyage of the ARAON includes the ice compressive strength, flexural strength, and failure strain of sea ice. This paper analyzes the gathered sea ice data in comparison with data from the first voyage of the ARAON during her Antarctic Sea ice trial in January 2010.

Development of Reliability Demonstration Test for Personal Blood Glucose Meters (개인용 혈당측정기의 신뢰성 보증시험 개발)

  • Kim, Gi-Young;Park, Ho-Joon;Park, Chan-Soo;Ham, Jung-Keol;Jang, Joong Soon
    • Journal of Applied Reliability
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    • v.13 no.4
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    • pp.299-307
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    • 2013
  • The value of blood sugar is measured by a personal blood glucose meter which consists of two parts: a glucose strip and a blood glucose meter. A personal blood glucose meter makes use of electric media which are composed of glucose oxidase and electron. This study is to propose a method of reliability demonstration test derived from field data analysis and FMEA(Failure Mode and Effect Analysis). Detailed Conditions for reliability demonstration test are selected from the comparison of various failure mechanisms. The most dominant failure mechanism is wear-out which is caused by strip insertion/extraction. The testing device that can reproduce the failure mechanism of strip insertion/extraction is made to conduct reliability demonstration test. Using the testing device, it is confirmed that target lifetime of selected devices is more than 2 years.

Remote monitoring technique for geotechnical structures using acoustic emission (미소파괴음을 이용한 지반구조물 원격계측기술)

  • Cheon, Dae-Sung;Jung, Yong-Bok;Park, Eui-Seob;Park, Chan;Jang, Hyun-Ick
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.946-956
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    • 2008
  • Acoustic emission(AE) is low-energy seismic event associated with a sudden inelastic deformation such as the sudden movement of existing fractures, the generation of new fractures or the propagation of fractures. These events rapidly increase before major failure and happen within a given rock volume and radiate detectable seismic waves. Rock slopes are usually large in scale and there are many discontinuities in rock mass. AE waves are strongly attenuated when they propagate through joints. Thus we should resolve the attenuation problem to monitor large volume. In this study, we developed waveguide which is composed of two different materials, cement mortar and stainless steel rod. And several laboratory tests on developed waveguide are performed to obtain generalized AE parameters to predict the failure stage in rock slope. Comparing field data with experimental data in laboratory tests, failure stage of rock slope can be evaluated. To verify and optimize the developed monitoring method, we are now carrying out the field application at a rock slope.

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A Study for Numerical Procedure of Strengthening Capacity in Field (사용중 보강되는 부재의 보강설계법 연구)

  • 한만엽;이원창
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10b
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    • pp.861-866
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    • 1998
  • This study is numerical procedure of strengthening capacity in a field structure and compare analysis data with test data. Recently, many strengthening methods are developed and used to rehabilitate existing structure. However, both theoretical background and applying techniques are not established yet. One of the most popular method is plate bonding method using either steel plate or carbon plate. This theoretical background and applying techniques are very important and those applications are differed when applied in field strengthening cases. Also depending on the analysis out come, displacement increased based n the condition of members while reaching ultimate load or failure load.

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Development of AI-Based Condition Monitoring System for Failure Diagnosis of Excavator's Travel Device (굴착기 주행디바이스의 고장 진단을 위한 AI기반 상태 모니터링 시스템 개발)

  • Baek, Hee Seung;Shin, Jong Ho;Kim, Seong Joon
    • Journal of Drive and Control
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    • v.18 no.1
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    • pp.24-30
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    • 2021
  • There is an increasing interest in condition-based maintenance for the prevention of economic loss due to failure. Moreover, immense research is being carried out in related technologies in the field of construction machinery. In particular, data-based failure diagnosis methods that employ AI (machine & deep learning) algorithms are in the spotlight. In this study, we have focused on the failure diagnosis and mode classification of reduction gear of excavator's travel device by using the AI algorithm. In addition, a remote monitoring system has been developed that can monitor the status of the reduction gear by using the developed diagnosis algorithm. The failure diagnosis algorithm was performed in the process of data acquisition of normal and abnormal under various operating conditions, data processing and analysis by the wavelet transformation, and learning. The developed algorithm was verified based on three-evaluation conditions. Finally, we have built a system that can check the status of the reduction gear of travel devices on the web using the Edge platform, which is embedded with the failure diagnosis algorithm and cloud.

A Case Study of RAM Analysis Using Field Data: Focusing on Korean Warship (야전운용제원을 활용한 RAM분석 사례: 해군함정을 중심으로)

  • Sohn, Jung-Mok;Chang, Chung-Moo;Won, You-Dong
    • The Journal of the Korea Contents Association
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    • v.12 no.12
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    • pp.395-412
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    • 2012
  • RAM analysis using field data is important and useful for acquisition and operation of weapon systems. But this kind of analysis didn't conducted due to the absence of weapon system's failure data in case of warship. This study suggest failure tracking process based on maintenance and repair parts consumption data and proves suggested method enables conducting RAM analysis. This method obtains validity through field operator's reviews. The results on 9 warships in this study significantly correspond with weapon system operator's experiences. Because the result of this study contains effects of various operational environments in field, it will useful for correction and verification on existing another weapon system's RAM estimates. If this kind of RAM data are sufficiently accumulated, it will be used to DB of korean unique RAM analysis.

Durability Improvement of High Pressure Seal for ISU under the Track Vibration (궤도진동에 대한 ISU 고압 시일 내구성능 개선)

  • Han, In-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.2
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    • pp.112-117
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    • 2009
  • The new suspension, called ISU(In-arm suspension system) was developed for Infantry Fighting Vehicle. During vehicle field test, early failure of ISU's sealing system was occurred after driving the paved road. From the failure analysis, ISU's displacement data was obtained. In analysis of PSD data, track induced vibration which has high frequency and small amplitude characteristics, was dominant. Such track vibration would result in early seal failure because of friction increase and lack of lubrication. To simulate track vibration environment in laboratory, seals were tested under the condition of 20Hz, ${\pm}1$, ${\pm}2mm$ amplitude. The same type of seal failure occurred in vehicle test, was reproduced in the lab test under ${\pm}1mm$ amplitude. From the test results, the durability of improved seal was increased by 2.5 times compared with the previous one.

Considerable Parameters and Progressive Failure of Rock Masses due to the Tunnel Excavation (터널 굴착시 고려해야 할 주변앙반의 매개변수와 진행성 파괴)

  • 임수빈;이성민
    • Proceedings of the Korean Geotechical Society Conference
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    • 1994.09a
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    • pp.231-234
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    • 1994
  • Concentrated stresses due to the tunnel excavation easily cause failure around opening in the soft rock mass layer. Thus, while excavatng tunnel in the soft rock mass layerm it is very important to predict the possibility of failure or yielding zones around tunnel boundary. There are two typical methods to predict these; 1) the analysis of field monioring data and 2) numerical analysis. In this study, it was attempted to describe the time-dependent or progressive rock mass manner due to the continuous failure and fracturing caused by surrounding underground openings using the second method. In order to apply the effects of progressive failure underground, an iterative technique was used with the Hoek and Brown rock mass failure theory. By developing and simulating, three different shapes of twin tunnels, this research simulated and estimated the proper size of critical pillar width between tunnels, distributed stresses on the tunnel sides, and convergences of tunnel crowns. Moreover, results out progressive failure technique based on the Hoek and Brown theory were compared with the results out of Mohr-Coulomb theory.

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The phenomenological study on the Experience of Korean Medicine Students who have academic failure (한의과대학생의 유급경험에 관한 현상학적 연구)

  • Shin, Heon Tae
    • Journal of Society of Preventive Korean Medicine
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    • v.20 no.2
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    • pp.53-67
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    • 2016
  • Objectives : The aim of this study was to explore the academic failure experiences of Korean Medicine Students. The academic failure in a medical school is defined as the situation the student who have academic failure need to repeat their academic year again. Methods : Data were collected through in-depth individual interviews from April to May 2016 and analyzed through Colaizzi's phenomenological methodology. The participants were interviewed twice, for 30minutes to 60minutes per interview. Results : Eight theme-clusters of were identified from 21 themes. The theme-clusters were 'Dream of university life and freedom', 'Meeting Stranger academic field and growing study stress', 'Difficulty of self-management', 'Weak supporting system', 'Feeling of guilty, sense of isolation and decreasing in self-esteem', 'The experience during the vacation after the academic failure', 'The experience of returning to school' and 'Self growing through hard experience'. Conclusions : Understanding of academic failure experience of Korean Medicine Students is an important approach to counsel them and an important way to reach a good model of education at a medical college.

A Study for FMEA and Optimization of Failure Diagnosis Sequence Using Probability of Failure Cause (고장원인 확률을 이용한 FMEA와 고장진단 순서의 최적화)

  • Song, Kee-Tae;Kim, Min-Ho;Baek, Young-Gu;Lee, Key-Seo;Kim, Soo-Myong
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.749-757
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    • 2007
  • Recently, with increasing interested in improvement of operational reliability and the systematic maintenance activities, the RCM analysis has been applied and tried to lots of applicable industries. This study covers applying the probability of failure cause to FMEA, and proposes an analytical method for this. Also, the measures of quantitative classification for the result of failure cause probability are addressed. Based on the field data, this thesis presents an identification for causes and characteristics of failure, and reviews them periodically from the above methodologies. As using FMEA applied the probability of failure cause, we in the future can look forward to improvement of efficiency for failure diagnosis & inspection, and reliability.

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