• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.3
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• pp.106-111
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• 2019

Pilot has been fighting to get over fatigue during flight and thought it as a hinderance for safe flight. The fatigue related problem has been the biggest obstacle for aviation safety so far. Even though pilots and airlines try their best to overcome fatigue during flight, they couldn't overcome this problem. So the airliners let the pilot sleep during flight if pilots are too tired with the report. It is controlled rest used and managed by several European airliners. So this study tries to get Korean airline pilots' fatigue information and figure out the cause and reduce it.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.129-132
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• 1991

The safe design against fatigue failure becomes more important criterion in highway bridges. The fatigue-safety evaluation is performed for the current bridge code. A reliability model incorporating fatigue damage is formulated and the satety indices are calculated. The present study indicates that the calculated safety indices vary greatly with traffic volumes and loadometer values. A method is proposed to maintain uniform reliability for vafious traffic conditions and loadings.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.59-63
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• 1993

It is very difficult to find not only optimized welding condition but also fatigue characteristics of the dissimilar weld. In this study. Low carbon steel (SS41) and austenitic stainless steel (STS304) were welded by GTAW welding with STS309 stainless wire rod and Single Edge Notch specimens were used for the examination of fatigue behavior on welding heat cycle. The fatigue crack growth rate in HAZ of SS41 was the highest. The second was in STS304 bond line and the lowest was in HAS of STS304.

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.27-36
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• 1997

This paper evaluates the static and fatigue bending strengths of CFRP (carbon fiber reinforced plastic) laminates subjected to hygrothermals. The specimens which had different stacking composition, orthotropic and quasi-isotropic laminated plates, were prepared for this experiment. A steel ball launched by the air gun collides against CFRP laminates to generate impact damages, and the 3-point fatigue bending test is carried out by using the impacted laminates to investigate the influence of hygrothermals on the effect on the residual bending fatigue strength of CFRP laminates.

• Journal of Auto-vehicle Safety Association
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• v.14 no.3
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• pp.30-34
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• 2022

The CFT(Cornering Fatigue test) and RFT(Radial Fatigue Test) are tests for evaluating the endurance of the disc and rim region of the wheel. In recent, automobile wheel safety standards have been revised and the applied load and target life criteria are different from existing conditions. The verification evaluation of all wheels requires a lot of time and cost. In this study, the endurance severity of each test was compared through strain-life approach by selecting 4 steel and 8 aluminum wheels.

• Journal of the Korean Society of Safety
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• v.21 no.6 s.78
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• pp.20-25
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• 2006

In the design of class 1 components to apply ASME code section III NB, a fatigue is considered as one of the important failure mechanisms. Fatigue analysis procedure and standard fatigue design curve(S-N curve) is suggested in ASME code, which had to be performed to meet the integrity of components at the design step. As the plant life extension for operating power plants and the long-lived plant design, however, are being progressed, the fact which the existing ASME fatigue design curve can not consider fatigue effects sufficiently comes to the fore. To find the technical solution for these problems, a number of researches and discussion are continued up to now. In this study, the detailed fatigue analyses using the 3 dimensional modeling for the fatigue-weakened components were performed to develop the optimized fatigue analysis procedure and their results are compared with other reference solutions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.241-249
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• 2003

The service life of steel bridges can be assured only when their strength, serviceability and fatigue safety are fulfilled. However, at the present time, the continuous research for fatigue of steel bridges is desperately required since not much research work has been done so far. In this study, a guideline on the fatigue design is suggested for the practical purpose in order to establish the long-term safety of steel bridges against fatigue. The continuous steel truss bridge was analyzed for the cumulative reversals of the actual traffic, stress ranges and fatigue strength. From the results, the domestic fatigue design procedure was found to be fairly overestimated in comparison to the design code of other foreign countries. Therefore, it is necessary to review the current fatigue design specifications and have the new and rationalized design criteria in the future domestic fatigue design guidance.

• Safety and Health at Work
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• v.12 no.4
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• pp.462-470
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• 2021

Background: Fatigue is pervasive, under-reported, and potentially deadly where flight operations are concerned. The aviation industry appears to lack a standardized, practical, and easily replicable protocol for fatigue risk assessment which can be consistently applied across operators. Aim: Our paper sought to present a framework, supported by real-world data with subjective and objective parameters, to monitor aircrew fatigue and performance, and to determine the safe crew configuration for commercial airline operations. Methods: Our protocol identified risk factors for fatigue-induced performance degradation as triggers for fatigue risk and performance assessment. Using both subjective and objective measurements of sleep, fatigue, and performance in the form of instruments such as the Karolinska Sleepiness Scale, Samn-Perelli Crew Status Check, Psychomotor Vigilance Task, sleep logs, and a wearable actigraph for sleep log correlation and sleep duration and quality charting, a workflow flagging fatigue-prone flight operations for risk mitigation was developed and trialed. Results: In an operational study aimed at occupational assessment of fatigue and performance in airline pilots on a three-men crew versus a four-men crew for a long-haul flight, we affirmed the technical feasibility of our proposed framework and approach, the validity of the battery of assessment instruments, and the meaningful interpretation of fatigue and work performance indicators to enable the formulation of safe work recommendations. Conclusion: A standardized occupational assessment protocol like ours is useful to achieve consistency and objectivity in the occupational assessment of fatigue and work performance.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.114-120
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• 2006

Inspection works are mainly carried out with the help of human sensory organs and are relatively simple and repetitive, so that the workers easily become to feel fatigue and monotony, and their mental activity levels attenuate. Consequently, during the work time, it is natural that various lighting conditions around the workplaces may have in-fluence on work performance. This study aimed to analyze cortical fatigue of inspection workers. Thus, an inspection work was simulated on a computer monitor under various lighting conditions, and CFF, EEG, EOG, and HRV were analyzed. According to the results, fatigue symptoms turned up about $60{\sim}90$ minutes after the onset of the work. The work performance also decreased when the fatigue symptoms due to lighting conditions turned up. The variations of fatigue and work performance were affected by illuminators, illumination levels, or interaction of those two factors. The spiral fluorescent lamp seemed improper to the inspection work, because the work performance under that condition was lower than under any other illuminators.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.20-27
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• 1999

The standard of the allowed stress in designing components such as shafts used in machinery and aircraft should be determined. It is very important to estimate fatigue strength of a component analytically, because service stress of the components is usually under the level of its fatigue limit. Improving the fatigue strength of each component in machinery is essential for high performance, lightness, and endurance. Surface treatment of components is widely used for these purpose. In this research, the fatigue behaviors of SCM415 steel and carbonitried SCM415 steel are examined. In the analysis of the fatigue behaviors of the carbonitrided SCM 415 steel, we propose a modified fatigue strength evaluation model and modified formulae.