• Korean Journal of Health Education and Promotion
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• v.26 no.4
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• pp.63-70
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• 2009

Objectives: Work stress is associated with increased risk of fatigue. The purpose of this study was to identify the relationship of work stress and fatigue among Medical Insurance Review Nurses. Methods: The subjects of this study were 117 nurses in charge of medical insurance review. A structured questionnaires were employed to evaluate the nurses' sociodemographics, work stress and fatigue. The data were analysed through frequency, percentile, mean, standard deviation, Chronbach's $\alpha$, Pearson's correlation coefficient, and multiple regression. Results: Mean scores of work stress and fatigue of participants were 3.29 and 1.97 respectively. Work stress was correlated with fatigue significantly (r=.39). There were effects on fatigue by work performance satisfaction and the frequency of insurance request among sociodemographics. Job conflicts with doctors which was a domain of work stress was increased fatigue. Conclusion: The results of this study suggest that work performance satisfaction, the frequency of insurance request and job conflicts with doctors are significant predictors of fatigue. Thus, a strategy to enhance nurses' work environment and to reduce work stress through developing interpersonal relationship is recommended.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.1
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• pp.173-179
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• 1997

The high temperature fatigue tests were performed using the specimens taken from Cr-Mo-V steel, widely used as thermal power plant turbine materials for examination fatigue behavior of materials in power plants which have been operated for long periods. The fatigue tests at high temperature were performed at the various temperature and applied stress. The results obtained are summarized as follows : The fatigue crack length increases and the fatigue life decreases with temperature and applied stress according to the same number of stress cycle. The fatigue crack propagation and the fatigue life were much influenced by temperature and applied stress.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.348-352
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• 2004

Recently the steel parts used for automiles and trains are required to be used under higher stress than ever before in need of the weight down. However, threr are a lot of problems with developing such of fatigue strength and fatigue life are mainly focused on by adopting residual stress. And got the following characteristics from crack growth test carried out stress ratio. Fatigue life shows more improvement in the Un-peening material. And Compressive residual stress of surface on the Shot-peening processed operate resistance force of fatigue. So we cam obtain fallowings. (1) The fatigue crack growth rate on stage II is conspicuous with the size of compressive residual stress and is dependent of Paris equation. (2) Although the maximum compressive residual stress is deeply and widely formed from surface, fatigue life does not improve than when maximum compressive residual stress is formed in surface. (3) The threshold stress intensity factor range is increased with increasing compressive residual stress.

• International journal of steel structures
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• v.18 no.4
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• pp.1242-1251
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• 2018

Not all loads contribute to fatigue crack propagation in the welded detail of steel bridges when they are subjected to variable amplitude loading. For fatigue assessment, therefore, non-contributing stress cycles should be truncated. However, stress range truncation is not considered during typical fatigue reliability assessment. When applying the first order reliability method, stress range truncation occurs mismatch between the expected number of cycles to failure and the number of cycles obtained at the time of evaluation, because the expected number of cycles only counts the stress cycles that contribute to fatigue crack growth. Herein, we introduce a calibration factor to coordinate the expected number of cycles to failure to the equivalent value which includes both contributing and non-contributing stress cycles. The effectiveness of stress range truncation and the proposed calibration factor was validated via case studies.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.120-126
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• 1998

Second step shot peening was applied on both smooth specimen and U-notch specimen in order to investigate the stress distribution and the improvement in fatigue strength. Various experiments and measurements such as rotary bending fatigue test and the measurement of compressive residual stress were performed. The results showed that the fatigue strength of second step shot peened specimens increased by 34 percent compared to that of unpeened ones. Compressive residual stress also considerably increased, which resulted in the increase of fatigue strength. finite element analysis showed that shot peening is effective in decreasing the bending stress by external force. The effectiveness of shot peening in reducing the compressive residual stress was anticipated by the superposition of the concentrated stress and the compressive residual stress.

• Journal of Welding and Joining
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• v.33 no.6
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• pp.49-54
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• 2015

Welding process is of importance to assemble products or structures, but also the process is structural weakness due to stress concentration in welding joint. The fatigue design of welded joint requires time & labor consuming fatigue test because the fatigue life is various according to the depth of joint, joint type and load type etc. In fatigue design codes, they guide to classify welding joints with their shape( BS7608, IIW Documents) and provide fatigue assessment information. In terms of numerical method for fatigue analysis, it is also difficult to decide the stress peak in joint because of mesh sensitivity which means that stress value is varies with element type or size on stress concentration zone. Hot-spot method is used generally, but Battelle of United States proposed Master S-N Curve based on structural stresses converted by mechanical equilibrium theory. In this research, we extracted master S-N curve from Battelle's fatigue test DB including test data of various welding joints to apply on Non-Load-Carrying cruciform Joint. Comparing fatigue results between the case of using normal stress and case of structural stress cor the cruciform Joint, The suggested Battelle method showed successive results.

• Journal of Ocean Engineering and Technology
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• v.25 no.5
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• pp.47-51
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• 2011

This paper analyzes the fatigue-life of welded joints using the notch stress approach. In the notch stress approach, the notch effects are usually approximated by introducing weld-bead parameters for the local detailed weld joints. The actual bead shape is complex and 3-dimensional. It may also greatly influence the fatigue strength. In this study, the welded shape was modeled using a 3D-scanner. The critical distance method was adopted in the evaluation of the fatigue effective notch stress for the weldments. Fatigue life tests were performed to verify the present method of fatigue life estimation for two types of welded plates with longitudinal attachments. The estimated results of the present methods were applied to the results of the experiment. The results of the analysis showed that the scatter of fatigue-life for the experimental data expressed in the nominal stress was significantly reduced by applying the effective fatigue stress of the present study.

• Korean Journal of Occupational Health Nursing
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• v.20 no.1
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• pp.74-82
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• 2011

Purpose: This study investigated how shift work nurses' fatigue influences job stress and turnover intention, and how job stress mediates the relationship between fatigue and turnover intention. Methods: As a descriptive research design, the data were collected from 203 shift work nurses in a city. It was analyzed using the SPSS/WIN 14.0 and AMOS 5.0. Results: fatigue and job stress in shift work nurses influenced turnover intention. Job stress worked as a partial mediation between fatigue and turnover intention. Conclusion: It is necessary to reduce fatigue and job stress for reducing turnover intention in strategies of hospital manpower.

• Korean Journal of Occupational Health Nursing
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• v.22 no.3
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• pp.208-217
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• 2013

Purpose: This study is a correlative study to assess the relationships of fatigue, stress, and burnout among the pregnant nurses in hospital. Methods: The subjects in this study were 103 nurses aged between 22 and 40 who were confirmed as pregnant by the OBGY (Obstetrics and Gynecology) hospital and working at medical facilities located in J-province of G city during the period of July 15 through September 15, 2010. Results: The level of fatigue of pregnant nurses showed an average of 5.60 out of 10 points, and the level of stress showed an average of 25.91. In terms of burnout, the average was 2.72 out of 5 points. The results of the correlative study to assess relationships among fatigue, stress and burnout showed significant positive correlation between burnout and fatigue (r=.47, p<.001) and stress (r=.53, p<.001) and between stress and fatigue (r=.58, p<.001). Therefore, the results show that increased level of fatigue and stress leads to increased level of burnout. Conclusion: The results of the study showed that higher level of fatigue and stress led to higher level of burnout. Therefore, to minimize the burnout of pregnant nurses, many efforts are required in the hospital policy and for the strategies to reduce burnout.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.133-141
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• 2006

The Low cycle fatigue behavior of 11.7Cr-1.1Mo heat-resisting steel has been investigated under strain-controlled conditions with mean stresses at room temperature and $300^{\circ}C$. For the tensile mean stress test, the initial high tensile mean stress generally relaxed to zero at room temperature, however, at $300^{\circ}C$ initial tensile mean stress relaxed to compressive mean stress. Low cycle fatigue lives under mean stress conditions are usually correlated using modifications to the strain-life approach. Based on the fatigue test results from different stain ratio of -1, 0, 0.5, and 0.75 at room temperature and $300^{\circ}C$, the fatigue damage of the steel was represented by using cyclic strain energy density. Total strain energy density considering mean stress indicated well better than not considering mean stress at $300^{\circ}C$. Predicted fatigue life using Smith-Watson-Topper's parameter correlated fairly well with the experimental life at $300^{\circ}C$.