• Title/Summary/Keyword: Fatigue Life relationship

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Fatigue life curves of alloy 617 in the temperature range of 800-950℃

  • Injin Sah;Jaehwan Park;Eung-Seon Kim
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.546-554
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    • 2023
  • The cyclical behavior of Alloy 617 was examined at 25 ℃ and high temperatures of 800, 850, 900, and 950 ℃ in air to obtain its fatigue life curves. The specimens tested at 25, 800, and 850 ℃ cyclically hardened, whereas those tested above 900 ℃ cyclically softened from the first cycle, that is, their fatigue life was reduced at high temperatures owing to loss of strength. Parameters of the typical Coffin-Manson-Basquin relationship were determined for each test temperature. Interestingly, no significant difference in fatigue life was observed for the specimens tested in the range of 800-950 ℃. Owing to the similarity in fatigue life, we determined fatigue strength and fatigue ductility exponents that could be applied for this temperature range. The parameters obtained were close to the universal slopes, although the fatigue ductility exponent was slightly different. The proposed fatigue life curves were compared with those presented in ASME code.

Low Cycle Fatigue Life Assessment of Alloy 617 Weldments at 900℃ by Coffin-Manson and Strain Energy Density-Based Models

  • Rando, Tungga Dewa;Kim, Seon-Jin
    • Journal of Power System Engineering
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    • v.21 no.1
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    • pp.43-49
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    • 2017
  • This work aims to investigate on the low cycle fatigue life assessment, which is adopted on the strain-life relationship, or better known as the Coffin-Manson relationship, and also the strain energy density-based model. The low cycle fatigue test results of Alloy 617 weldments under $900^{\circ}C$ have been statistically estimated through the Coffin-Manson relationship according to the provided strain profile. In addition, the strain energy density-based model is proposed to represent the energy dissipated per cycle as fatigue damage parameter. Based on the results, Alloy 617 weldments followed the Coffin-Manson relationship and strain energy density-based model well, and they were compatible with the experimental data. The predicted lives based on these two proposed models were examined with the experimental data to select a proper life prediction parameter.

The Relationship of Symptoms of Side Effects, Fatigue and Quality of Life in Stomach Cancer Patients receiving Chemotherapy (수술후 화학요법받는 위암환자의 부작용 증상, 피로 및 삶의 질과의 관계)

  • Yang, Young-Hee
    • Korean Journal of Adult Nursing
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    • v.14 no.2
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    • pp.205-212
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    • 2002
  • Purpose: The purpose of this study was to investigate the level of nausea, vomiting, anorexia, fatigue and quality of life as well as to determine the relationship between those variables and identify the influencing factors on fatigue and quality of life in stomach cancer patients receiving adjuvant chemotherapy. Method: Subjects were 94 stomach cancer patients undergoing postoperational chemotherapy in a general hospital in Seoul. Nausea and vomiting were measured with Rhodes et al(1984) and anorexia with one 5-point item. Fatigue was measured using Lee's tool(1999) except open questions. The tool for quality of life was modified based on the Quality of Life Index by Padilla et al(1983). Result: Subjects reported low level of fatigue(mean=3.86, range=0-10) compared with the results of previous researches and moderate quality of life(mean=2.64, range=1-4). Fatigue was positively correlated with nausea, vomiting and anorexia(r=.21 ~ .55, p<.05). Quality of life was negatively correlated with nausea, vomiting, anorexia(r= -.24 ~ -.45, p<.05) and fatigue (r=-.61, p<.01). Multiple regression analysis revealed that activity level, vomiting before admission, anorexia during chemotherapy and age explained 52.8% of the variance in fatigue. Fatigue, anorexia before admission, age and sex explained 50.5% of the variance in quality of life. Fatigue and quality of life were not influenced by the stage of disease, nor weight change. Conclusion: These results may contribute to a better understanding of how much the side effects of anticancer drugs can affect fatigue and quality of life in cancer patients undergoing chemotherapy. Also it is the remarkable fact that symptoms remaining after discharge such as vomiting or anorexia continued until re-admission, contributing to patients fatigue and lowered their quality of life.

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The correlation analysis between fatigue and health promoting life style among a rural college students (일 지역 대학생의 피로와 건강증진 생활양식과의 관계분석)

  • Jang Hee-Jung
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.6 no.3
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    • pp.477-492
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    • 1999
  • The disease patterns among the Korean was shifted from acute and infectious diseases to chronic diseases. According to the these disease patterns trends, people have concerned about the health promotion and health behaviors. Pender's(1996) revised health promotion model(HPM) is consist of three categories; Individual characteristics and experiences, Behavior-specific cognitions and affect, behavioral outcome. Of these categories, individual characteristics and experiences, this category of variables is considered to be of biological, psychological and socio-cultural personal factors, especially, individual fatigue. Futhermore. these variables constitute a critical core for nursing intervention, as they are subject to modification through nursing actions. But there is no few the research of the relationship between the fatigue and health promotion. Therefore, the purpose of this study is to investigate the correlation between the fatigue and health promoting life style among a rural college students. Additionally, this descriptive correlational study identified the relation of demographic factors and fatigue, health promoting life style. From June 20 to 26, 1998, a convenience sample of 270 college students completed the questionnaire of the fatigue and health promoting life style profile which were developed by the Yoshitake(1978) and Walker, et al.(1987), respectively. The descriptive correlational statistics, mean, t-test, ANONA, Pearson correlation coefficient were used to analyze the data gathered with SAS pc+ program. The results were as it follows: 1. The average fatigue score of the subjects was $64.93{\pm}12.89$. Fatigue scores by subcategory were physical symptoms($23.5{\pm}4.87$). psychological symptoms($22.11{\pm}4.66$) and neuro-sensory symptoms($19.32{\pm}5.14$). With the respect to the demographic characteristics of the subjects, there were statistically significant differences between the demographic factors and fatigue, especially, sex(t==3.69 p<0.01), major(t=-2.89 p<0.01). the experience of family illness(t=2.76 p<0.01). 2. The average health promoting life style item score of the subjects was $2.33{\pm}0.33$. In the subcategories, the highest degree of performance was self-actualization(2.94), following interpersonal support(2.81). stress management(2.33), exercise(2.20), nutrition(2.10), and the lowest degree was health responsibility(1.73). There were the significant differences on the learning of health education(t=2.00 p<0.01). religion(F=3.01, p<0.05), circle activity(t=2.07, p<0.05), nutrition control(t=5.25, p<0.01) of demographical factors with the health promoting life style. 3. The correlation between the fatigue and health promoting life style made statistically no significance(r=-0.09731, p>0.05). But there was negative significant relationship between health promoting life style and psychological symptom as a fatigue subcategory(r=-0.15721, p<0.05). The self-actualization showed negative significant correlation with all fatigue subcategory. The health responsibility showed significant relationship with total fatigue(r=0.13050. p<0.05). For further research, it suggests to replicate the correlational and causal study between the fatigue and the health promoting life style using the another fatigue scale which is able to measure the subjective and objective fatigue degree. And it needs to develop the nursing intervention program for maintaining and promoting the health behavior as well as for decreasing the college students's fatigue.

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Effects of Fatigue and Postpartum Depression on Maternal Perceived Quality of Life (MAPP-QOL) in Early Postpartum Mothers (초기 산욕기 산모의 피로와 산후우울이 지각된 삶의 질에 미치는 영향)

  • Choi, So-Young;Gu, Hye-Ja;Ryu, Eun-Jeong
    • Women's Health Nursing
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    • v.17 no.2
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    • pp.118-125
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    • 2011
  • Purpose: This study was done to identify effects of fatigue and postpartum depression on quality of life in early postpartum mothers. Methods: The data were collected from 130 mothers at four general hospitals in J and M metropolitan cities. Instruments used to collect the data for the study were the Fatigue Scale developed by Pugh (1993); Postpartum Depression Scale developed by Cox, Holden & Sagovsky (1987), and the Quality of Life Scale developed by Hill, Aldag, Hekel, Riner, G., & Bloomfield (2006). Results: Results showed that the mean for fatigue was 56.74, the mean for postpartum depression was $8.00{\pm}4.37$ and mean for quality of life was 19.78. The quality of life variable showed statistically significant differences for the variable: age (F=3.20, p=.026). The relationship between fatigue and quality of life showed a significant negative correlation (r=-.44, p<.001). The relationship between postpartum depression and quality of life also showed a negative correlation (r=-.42, p<.001). The relationship between postpartum depression and fatigue showed a positive correlation (r=.59, p<.001). These factors explained 23% of the variance in quality of life. Conclusion: The results indicate that it is necessary to develop nursing intervention programs to improve quality of life in for early postpartum mothers.

Overload Analysis and Fatigue Life Prediction Using an Effective J-Integral of Spot Welded Specimens (점용접시편의 과부하해석 및 유효 J-적분에 의한 피로수명예측)

  • Lee, Hyeong-Il;Choe, Jin-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.567-580
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    • 2000
  • This paper proposes an integrated approach, which is independent of specimen geometry and loading type, for predicting the fatigue life of spot welded specimens. We first establish finite element models reflecting the actual specimen behaviors observed on the experimental load-deflection curves of 4 types of single spot welded specimens. Using finite element models elaborately established, we then evaluate fracture parameter J-integral to describe the effects of specimen geometry and loading type on the fatigue life in a comprehensive manner. It is confirmed, however, that J-integral concept alone is insufficient to clearly explain the generalized relationship between load and fatigue life of spot welded specimens. On this ground, we introduce another effective parameter $J_e$ composed of $J_I$, $J_{II}$, $J_{III}$, which has been demonstrated here to more sharply define the relationship between load and fatigue life of 4 types of spot welded specimens. The crack surface displacement method is adopted for decomposition of J, and the mechanism of the mixed mode fracture is also discussed in detail as a motivation of using $J_e$.

Fatigue Behavior of Welded Joints in HT60 Grade TMCP Steel (HT60급 TMCP강 용접부의 피로 거동)

  • Yong, Hwan Sun;Kim, Seok Tae;Cho, Yong Sik
    • Journal of Korean Society of Steel Construction
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    • v.8 no.4 s.29
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    • pp.133-133
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    • 1996
  • Application of the relationship $da/dN=C({\Delta}K)^{m}$ is effective in the analysis of fatigue crack growth life. The values of material constant C and m have great influences on the predicted fatigue life and the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(${\Delta}K$) is effective in fatigue crack growth behavior. In this paper, fatigue crack growth behavior of the welded joints in HT60 grade TMCP(Thermo Machanical Control Process) steel have been studied. To evalute the fatigue crack growth rates of HT60 grade TMCP steel, fatigue test was performed by base metal(BM), heat affected zone(HAZ) and weld metal(WM) in TMCP steel at room temperature. We determined the relationship of $da/dN-{\Delta}K$ by correlation between C and m obtained from the Paris-Erdogan power law data supplied HT60 grade TMCP steel. The obtained results from this study indicate that fatigue crack growth rate of TMCP steel is not influenced by softening effect which occurs in the HAZ when high heat input weld is carried out. Softening effects, which affect fatigue properties. are shown that it is not affected to the fatigue growth rates significantly.

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Fatigue Properties of Copper Foil and the Evolution of Surface Roughness

  • Oh, Chung-Seog;Bae, Jong-Sung;Lee, Hak-Joo
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.4
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    • pp.57-62
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    • 2008
  • The aim of this investigation was to extract the fatigue properties at the designated fatigue life of copper foil and observe the mean stress and stress amplitude effects on both the fatigue life and the corresponding surface morphology. Tensile tests were performed to determine the baseline monotonic material properties of the proportional limit and ultimate tensile strength. Constant amplitude fatigue tests were carried out using a feedback-controlled fatigue testing machine. The mean stress and the stress amplitude were changed to obtain the complete nominal stress-life curves. An atomic force microscope was utilized to observe the relationship between the fatigue damage and the corresponding changes in surface morphology. A Basquin's exponent of-0.071 was obtained through the fatigue tests. An endurance limit of 122 MPa was inferred from a Haigh diagram. The specimen surface became rougher as the number of fatigue cycles increased, and there was a close relationship between the fatigue damage and the surface roughness evolution.

Statistical Life Prediction of Fatigue Crack Growth for SiC Whisker Reinforced Aluminium Composite (SiC 휘스커 보강 Al6061 복합재료의 통계학적 피로균열진전 수명예측)

  • 권재도;안정주;김상태
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.2
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    • pp.475-485
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    • 1995
  • In this study, statistical analysis of fatigue data which had obtained from respective 24 fatigue crack, was examined for SiC whisker reinforced aluminium 6061 composite alloy (SiC$_{w}$/A16061) and aluminium 6061 alloy. SiC volume fraction in composite alloy is 25%. The analysis results stress intensity factor range and 0.1 mm fatigue crack initiation life for SiC$_{w}$/A16061 composite & A16061 matrix are the log-normal distribution. And regression analysis by linear model, exponential model and multiplicative model were performed to find out the relationship between fatigue crack growth rate(da/dN) and stress intensity for find out the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(.DELTA.K) in the SiC$_{w}$/A16061 composite and examine the applicability of Paris' equation to SiC$_{w}$A16061 composite. Also computer simulation was performed for fatigue life prediction of SiC$_{w}$/A16061 composite using the statistical results of this study.udy.

Effects of Pain, Sleep Disturbance, and Fatigue on the Quality of Life in Patients with Pancreatic Cancer Undergoing Chemotherapy (항암화학요법을 받는 췌장암 환자의 통증, 수면장애, 피로가 삶의 질에 미치는 영향)

  • Kim, Gyung-Duck;Jang, Hyun-Jin
    • Asian Oncology Nursing
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    • v.12 no.2
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    • pp.117-124
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    • 2012
  • Purpose: The purpose of this study was to assess pain, sleep disturbance, fatigue, and the quality of life and to identify the impact of pain, sleep disturbance and fatigue on the quality of life in patients with pancreatic cancer undergoing chemotherapy. Methods: Data were collected from June to July, 2010. Participants were recruited from Y university hospital in Seoul. Research instruments included numeric rating scale for pain, Functional Assessment Chronic Illness Therapy-Functional Well-Being (FACIT-FWB): General Factor 5 (GF5) for sleep disturbance, Functional Assessment of Cancer Therapy-General (FACT-G) for quality of life, and FACT-Fatigue for fatigue. Results: The quality of life for cancer patients had a significant relationship with pain, sleep disturbance, and fatigue. The significant factors influencing quality of life were pain, sleep disturbance, and fatigue that explained 52.6% of the variance. Conclusion: Patients with pancreatic cancer undergoing chemotherapy experienced pain, fatigue, and sleep disturbance which led to a negative effect on quality of life. The results suggest that intervention program to improve quality of life could reduce pain, fatigue, and sleep disturbance of pancreatic cancer patients undergoing chemotherapy.