• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2012년도 춘계학술대회
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• pp.59-60
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• 2012

• 근관절건강학회지
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• 제6권1호
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• pp.51-72
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• 1999

The purpose of this study is to compar self-reported fatigue and fatigue-regulating behaviors of rheumatoid arthritic patients and normal persons. This study collected the data from 75 rheumatoid arthritic patents visited the departments of internal medicine or orthopedics of four general hospitals T-city and K-city by means of direct interview and questionnaires. in this study also collected data from 75 normal persons who had not been exposed to any other disease in T-city and K-city by means of direct interviews anti questionnaires which were conducted by two trained nurses. This experiment was conducted from August 1, 1998 to October 15, 1998. This study used both MAP(Multi-Dimentional Assessment of Fatigue) developed by Belza(1995) to measure fatigue and the measurement developed by Kwon, Young-Eun to investigate fatigue regulating behaviors. The collected materials were analyzed by means of descriptive statistics, t-test, and the ANCOVA according to the SPSS PC+ program. The findings are as follows : 1. There was the statistically significant difference(t =5.07, p=.000), between rheumatoid arthritic patients(32.76 points) and normal persons(25.81 points) in t-test comparison by group about fatigue. A fatigue degree of rheumatoid arthritic patient group was high in five kinds of lower realms such as common fatigue degree, fatigue severity to be experienced, distress due to fatigue, daily fatigue degree, and fatigue timing at the last week by dimension. 2. There was the significant difference in the number of fatigue-regulating behaviors between rheumatoid of fatigue arthritic patients(9.37 times) and normal persons (8.15 times), but there wasn't any significant difference in the efficiency between rheumatoid arthritic patients(2.85 points) and normal persons (2.78 points) This research suggests two kinds of things as follows : 1. It is necessary to develop an educational program for improving efficiency of fatigue-regulating behaviors as well as some nursing arbitration measures for reducing fatigue of rheumatoid arthritic patients. 2. It is necessary for the future studies to continuously grasp characteristics of fatigue by gender variable by selecting more rheumatoid arthritic male patients.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.65-70
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• 2007

Welding is the most commonly used method to produce bogie and carbody of Electrical Multiple Units(EMU), because it increases the strength and lowers the weight of EMU. Since bogies are constantly exposed to repeated reacting load during acceleration and deceleration, it is also true that crack normally occurs at welding parts. In this study, we have investigated the fatigue strength of SS400 on welded parts in order to find efficiency of treatment after welding by shot peening and Post-Weld heat treatment(PWHT) with butt welded specimens. The results of fatigue test indicate that the measurement of base material specimen is 236MPa, welded specimen is 132MPa and the specimen of PWHT is 107MPa approximately. We concluded that the measurement of welded specimen and PWHT is approximately 44 and 54 percents lower than the base material specimen, respectively. Another finding is that the peened specimen is approximately 23 and 61 percents higher than the base material specimen in terms of the fatigue in strength of specimens.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.447-452
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• 2001

An automated system is developed to perform fatigue crack growth tests under constant effective stress intensity factor range ${\Delta}K_{eff}$. In the system, crack length and crack opening load are measured in real-time by using the unloading elastic compliance method. The system consists of two personal computers, an analogue electrical subtraction circuit, a stepping motor, a stepping motor driver, a PIO board, and the application software used to integrate the whole system. The performance of the developed system was tested and discussed performing constant ${\Delta}K_{eff}$ crack growth tests on a CT specimen of 7075-T6 aluminum alloy. The performance of the system is found to be strongly dependent on the accuracy of measurements of crack opening load. Besides constant ${\Delta}K_{eff}$ testing, the system is expected to be successfully applied for automation of various fatigue tests.

• 대한기계학회논문집
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• 제13권5호
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• pp.901-910
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• 1989

본 연구에서는 2상계 스테인리스강의 모재 및 용접부에 대하여 대기중의 피로시험과 인공해수중의 부식피로 시험을 모재부와 용접부의 .alpha.,.gamma.상의 상비율 변화에 따른 조직의 변화 및 용접잔유응력의 영향이 크랙전파에 미치는 영향을 검토하였다. 응력-스트레인의 히스테리스곡선에서 균열닫힘 거동을 실측하고 이들의 결과로 부터 유효응력확대계수와 균열전파속도와 관계를 정리하여 이들의 문제를 해석하였다.

• 한국콘텐츠학회논문지
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• 제14권11호
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• pp.175-185
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• 2014

이 연구는 민간경비원의 피로를 효과적으로 관리하기 위한 민간경비원에 맞는 피로도 척도를 개발하여 타당도와 신뢰도를 검증하였다. 이러한 연구목적을 달성하기 위해서 이 연구에서는 2014년 서울지방경찰청에 등록된 경비회사에 재직하고 있는 시설경비종사자를 연구대상으로 설정하고, 유의표집법을 활용하여 300명의 표본을 추출하였으나, 최종분석에 사용한 사례수는 259명 이다. 피로도 척도는 선행연구를 토대로 척도개발 방법 및 절차를 통하여 개발하였다. 자료처리는 SPSSWIN 18.0을 활용하여 탐색적 요인분석, 신뢰도분석, 상관분석을 실시하였으며, AMOS 18.0을 활용하여 확인적 요인분석을 실시하였다. 결론은 다음과 같다. 첫째, 피로도 측정도구의 타당도는 높다. 즉, 내용타당도는 높았으며 구성타당도 또한 높다. 탐색적 요인분석의 경우 .452의 요인적재치를 보였으며, 확인적 요인분석의 경우 .403의 표준치를 나타내고 있어 적합지수도 기준치를 충족시켜주고 있다. 타당도 검증을 통해 최종적으로 도출한 피로도의 하위개념은 정신적 피로, 신경계 기능장애, 신체적 부조화, 소진이다. 둘째, 피로도 측정도구의 신뢰도는 높다. 즉, 문항분석을 통해 문항과 하위영역간, 문항과 총점간의 상관관계가 .602이상으로 비교적 높다. 그리고 신뢰도 계수는 Cronbach's ${\alpha}=.658$이상으로 높다. 본 연구에 의해서 개발된 민간경비원의 피로도 척도 도구는 타당도와 신뢰도가 검증되어 기존의 타 영역에서 연구되어 사용하고 있는 도구보다 민간경비원의 피로를 확실하게 측정할 수 있을 것이다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 춘계학술대회
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• pp.88-91
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• 1994

We develope a assistant system of foot pressure distribution for improvement gait Pattern, adapted working speed, and minimitation of muscle fatigue of the sensory feedback type FES system(SEFES). This measurement system consist of mat type pressure sensor with piezo electric films. The pressure data signal multiflexed input scanning method processed A/D conversion after two step amplify and integrate. Matrix sensor interface to PC for pseudo color display by level of Pressure distribution data. This measurement system clinically evaluated in hemiplegic patients. It has produced acceptable results with optimal location of the food sensor's pressure point and avoid the muscle fatigue.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.385-389
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• 2004

Test facilities for the wind turbine performance monitoring and mechanical load measurements are installed in Vestas 100 kW wind turbine in Wollyong test site, Jeju island. The monitoring system consists of Garrad-Hassan T-MON system, telemetry system for blade load measurement, various sensors such as anemometer, wind vane, strain gauge, power meter, and etc. The experimental procedure for the measurement of wind turbine loads, such as edgewise(lead-lag) bending moment, flapwise bending moment, and tower base bending moment, has been established. Strain gauges are on-site calibrated against load cell prior to monitoring the wind turbine loads. Using the established monitoring system, the wind turbine is remotely monitored. From the measured load data, the load analysis has been performed to obtain the load power spectral density and the fatigue load spectra of the wind turbine.

• 한국기계가공학회지
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• 제7권1호
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• pp.62-66
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• 2008

Machine parts subjected to fluctuating or cyclic loads induce repeated stresses that often result in failure by fatigue. In such cases, the fatigue failures unfortunately sometimes occur. These may arise from a lack of knowledge with regard to the design, fabrication and operation of the machines or structures. The failure analysis provides valuable information regarding the prevention of similar failures. Furthermore, this information will be useful to improve or to develop new products. Failure stress analysis is classified into X-ray fractography. X-ray fractography has the limited applications because of material crystal size, difficult measurement method, electrolytic polishing precision, and long test time. Therefore, this study proposed the new method to improve the measurement precision of plastic zone depth and test time using TRIZ.

• 비파괴검사학회지
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• 제22권2호
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• pp.155-169
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• 2002

피로균열 진전시 균열 열림 및 닫힘에 따른 음향방출 특성을 규명하고자 구조용 알루미늄 2024-T4 와 6061-T6 재료에 대해 소형인장 시편에서의 피로균열 진전시 발생되는 AE 특성을 관찰하였으며, 기존의 AE파라미터 분석은 물론 재료의 파단면 분석을 통해 재료특성에 따른 AE 발생거동 사이의 관계를 논의하였다. 대부분의 음향방출 신호는 균열이 열리기 시작하는 위상과 균열이 완전히 닫히는 위상에서 많이 발생되었으며 하중을 최대로 받는 균열 완전 열림에서는 전반적으로 적게 발생됨을 알 수 있었다. 또한 재료에 따라서 균열 완전 열렴 부분에서 발생하는 음향방출 특성은 달라졌으나 각 피로 사이클 주파수 변화 (0.1, 0.2, 1.0Hz)에 따른 결과에서는 통일 재료일 경우 피로 사이클 주파수가 변화하더라도 각 사이클에서의 AE hit 발생 경향용 비슷하게 나타났다. 이와 같은 결과로부터 균열 열림 및 닫힘시 재료 의 미세조직과 기계적 특성인 연장강도와 항복강도에 따라 AE 특성이 달라질 수 있음을 알 수 있었다.