• 근관절건강학회지
• /
• 제6권1호
• /
• pp.51-72
• /
• 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.

• 한국세라믹학회지
• /
• 제34권9호
• /
• pp.927-934
• /
• 1997

Static and cyclic fatigue tests were carried out for alumina specimen to study the statistical analyses (normal, lognormal and Weibull distribution) of fatigue lifetime data and nominal initial crack length data. Fatigue lifetime data followed Weibull distribution better than normal or lognormal distribution, for the shape parameter of the notched specimen was larger than that of the unnotched specimen. The nominal initial crack length data obtained from fatigue lifetime followed the lognormal and Weibull distribution better than normal distribution, for the coefficient of variation of the unnotched specimen was larger than that of the notched specimen, and shape parameter of unnotched specimen was smaller than that of the notched specimen.

• Composites Research
• /
• 제30권6호
• /
• pp.406-409
• /
• 2017

The thin-walled cylindrical tubes are frequently used for the evaluation of fatigue property of composites. But the curvature of the tubular specimen induces interlaminar normal stress which may affect the fatigue property. In this paper interlaminar normal stress effect on the fatigue behaviour of thin-walled graphite/epoxy tubes $[{\pm}45]_s$ composites was studied experimentally. It was concluded that the interlaminar normal stress induced by the curvature of the cylinder has no discernible effect on the fatigue life. But excessive internal pressure can produce the stiffness increase and this affects the fatigue life of the cylindrical tubular composite.

• Structural Engineering and Mechanics
• /
• 제11권3호
• /
• pp.301-314
• /
• 2001

The purpose of this experimental study is to investigate the damage mechanism due to shear-fatigue behavior of high-strength reinforced concrete beams under repeated loading. The relationship between the number of cycles and the deflection or strain, the crack growths and modes of failure with the increase of number of cycles, fatigue strength, and S-N curve were observed through a fatigue test. Based on the fatigue test results, high-strength reinforced concrete beams failed at 57-66 percent of static ultimate strength for 2 million cycles. The fatigue strength at 2 million cycles from S-N curves was shown as about 60 percent of static ultimate strength. Compared to normal-strength reinforced concrete beams, fatigue capacity of high-strength reinforced concrete beams was similar to or lower than fatigue capacity of normal-strength reinforced concrete beams. Fatigue capacity of normal-strength reinforced concrete beams improved by over 60 percent.

• 대한예방한의학회지
• /
• 제19권2호
• /
• pp.67-74
• /
• 2015

Objective : The aim of this study was to investigate fatigue-related factors including socio-demographic variables and life styles among workers in the automobile manufacturing industry. Method : The subjects were 22,937 individuals who had received health examination by Korean Medical doctors and responded to questionnaires for 8 months from March to November in 2011. The fatigue index was measured by heart rate variability (HRV) in an automobile manufacturing industry. A multivariate analysis with SPSS version 19.0 was used to examine the relationship between fatigue and other factors including ages, smoke consumption, drinking frequency, exercise frequency, occupational category, conjugal condition. Results : In comparison between normal and very bad level of fatigue, factors of ages, smoking, drinking, and exercise showed significant difference(p<0.05). In addition, when normal and bad fatigue were compared, ages, smoking, exercise also produced significant difference(p<0.05). Furthermore, in normal and good level of fatigue comparison, occupation and smoking yielded significant difference(p<0.05). Finally, in other comparisons between normal and very good fatigue, exercise, smoking and occupation revealed significant difference(p<0.05). Conclusion : The results of this study suggest that age increase affects fatigue negatively, whereas exercise and drinking of once or twice per a week can have positive correlations.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2002년도 춘계학술대회 논문집
• /
• pp.104-109
• /
• 2002

In this paper, a statistical analysis of fatigue crack growth behavior under constant amplitude loads has been carried out. Fatigue crack growth tests were conducted on sixteen pre-cracked compact tension (CT) specimens of the pressure vessel (SPV50) steel in controlled identical load and environmental conditions. The assessment of the statistical distribution of fatigue crack growth experimental data obtained from SPV50 steel was studied and also the correlation of the parameter C and m in the Paris-Erdogan law was discussed. The probability distribution function of fatigue crack growth life seems to follow the 3-parameter Weibull. The fatigue crack growth rate seems to follow the 3-parameter Weibull and the log-normal distribution. The coefficient of variation (COV) of fatigue crack growth life was observed to decrease as the crack grows. A strong negative linear correlation exists between the coefficient C and the exponent m in Paris model. Fatigue crack growth rate data shows a normal distribution for both m and logC.

• 대한기계학회논문집A
• /
• 제27권6호
• /
• pp.923-929
• /
• 2003

In this paper, an analysis of fatigue crack growth behavior from a statistical point of view has been carried out. Fatigue crack growth tests were conducted on sixteen pre-cracked compact tension (CT) specimens of the pressure vessel (SPV50) steel in controlled identical load and environmental conditions. The assessment of the statistical distribution of fatigue crack growth experimental data obtained from SPV50 steel was studied and also the correlation of the parameter C and m in the Paris-Erdogan law was discussed. The probability distribution function of fatigue crack growth life seems to follow the 3-parameter Weibull. The fatigue crack growth rate seems to follow the 3-parameter Weibull and the log-normal distribution. The coefficient of variation (COV) of fatigue crack growth life was observed to decrease as the crack grows. Fatigue crack growth rate data shows a normal distribution for both m and logC. A strong negative linear correlation exists between the coefficient C and the exponent m.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2002년도 추계학술대회 논문집(I)
• /
• pp.150-155
• /
• 2002

En case of the fatigue life evaluation of rolling stock structures, mainly deterministic fatigue life evaluation has been carried out. But most of the parameters influencing on the fatigue life have a probabilistic distribution such as normal, log-normal, Weibull, etc. Therefore, to take probabilistic factors into fatigue life evaluation, probabilistic methods are being applied to the fatigue life evaluation of rolling stock. In this paper, probabilistic S-N analysis and methods using limit state functions are introduced. And some results of fatigue life evaluation obtained with these methods for rolling stock structures are shown.

• 대한가정학회지
• /
• 제27권1호
• /
• pp.47-58
• /
• 1989

This study was undertaken to investigate whether the stress caused by day/night shifts on industrial workers can be affected through nutritional status. A sample of 573 female industrial workers, aged 17 through 23 years, from 4 different industries (2 in normal, 2 in 3 shift work pattern) were surveyed by questionaire examining their nutritional status, food intake, dietary habit, sleep complaint, performance of digestive organs, and degree of fatigue. Shift workers were surveyed during night work. The results are summarized as follows: 1. Sleep complaints and degree of fatigue in shift workers were higher than normal workers, whereas the performance of digestive organs were as lower than normal workers. These results showed that shift workers were more stressed than normal workers. 2. The workers who were surveyed were all poor in nutritional status. The intakes of calorie, protein, Ca, riboflavin, and ascorbic acid were lower than Korean Recommanded Dietary Allowences (RDA). Dietary habit of the shift workers was irregular. 3. There was a negative correlation between nutritional status and degrss of fatigue. The intakes of energy nutrients, ascorbic acid, and niain were significantly related to the degree of fatigue in which protein intake was found to be most influential. Among workers with the same level of protein intake, shift workers showed higher degree of fatigue. When the protein intake of shift workers was 100-125% of R.D.A., they showed the same degree of fatigue to the average normal workers.

• 국제물리치료학회지
• /
• 제4권1호
• /
• pp.488-493
• /
• 2013

The purpose of this study was to investigate spirometric lung pattern, respiratory function and degree of fatigue by lung function tests and fatigue tests of 39 elderly people in a care facility aged 65 and over. The respiratory function tests were used to the Spirovit SP-1 and fatigue tests were used modified Piper fatigue scale(mPFS). Regarding the respiratory function, the FVC was $1.41{\pm}0.36$l, the FVC % predicted was $69.10{\pm}14.98$%, the $FEV_1$ was $1.02{\pm}0.31$l, the $FEV_1$ % predicted was $63.27{\pm}16.05$%, the $FEV_1$/FVC was $72.77{\pm}13.40$%, and the fatigue score was $5.83{\pm}1.09$. As for the spirometric lung pattern, 19 patients had a restrictive pattern(48.7%), followed by 11 with a mixed pattern(28.2%), 5 with an obstructive pattern( 12.8%), and 4 with a normal pattern(10.3%). Regarding the respiratory function and fatigue by spirometric lung pattern, the FVC and the FVC % predicted of patients with a normal pattern or an obstructive pattern were greater than other groups at a statistically significant level. As for the $FEV_1$, that of patients with a normal pattern was significantly higher than others, and for the $FEV_1$ % predicted, that of patients with a normal pattern or a restrictive pattern was significantly higher(p<.001). Fatigue score by patients with a normal pattern was significantly less than patients of other patterns(p<.001). Therefore, pulmonary physical therapy is considered necessary to improve respiratory function and fatigue degradation of elderly in a facility.