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5083-H113 A1合金에 있어서 균열닫힘을 考廬한 表面균열 進展擧動과 그 機構
辛龍承 서울産業大學校 1988 논문집 Vol.27 No.1
Surface crack propagation is an important problem which deals with the development of defects just after their initiation. In this study, the propagration and closure behavior of surface crack initiated at a sharply notched specimens were ivestigated in 5098-H113 aluminium alloy by the unloding elastic compliance method. The crack shape (aspect ratio) was found to be approximately semi-circular during the crack was being small and to be changed to semi- elliptical during it was being long. The propagation rate of a surface crack initiated from norch root decelerated with increasing crack kenth when the crack waas small and then accelerated when it was large. The effect of stress intensity ratio was large in lower△K range, but the effective stress intensity factor range, △K ,was found to diminish the difference of the crack propagation rate. The plasticity-induced and roughness-induced crack closure mechamisms were predominant in the range of this study.
신용승,하종식 환경독성보건학회 2012 환경독성보건학회지 Vol.27 No.-
Climate change, caused by global warming, is increasingly recognized as a major threat to mankind’s survival. Climate change concurrently has both direct and modifying influences on environmental, social, and public health systems undermining human health as a whole. Environmental health policy-makers need to make use of political and technological alternatives to address these ramifying effects. The objective of this paper is to review public health policy in Korea, as well as internationally, particularly as it relates to climate change health adaptation and mitigation programs (such as C-CHAMP of Korea), in order to assess and elicit directions for a robust environmental health policy that is adaptive to the health impacts of climate change. In Korea, comprehensive measures to prevent or mitigate overall health effects are limited, and the diffusion of responsibility among various government departments makes consistency in policy execution very difficult. This paper proposes integration, synergy, and utilization as the three core principles of policy direction for the assessment and adaptation to the health impacts of climate change. For specific action plans, we suggest policy making based on scientifically integrated health impact assessments and the prioritization of environmental factors in climate change; the development of practical and technological tools that support policy decisions by making their political implementation more efficient; and customized policy development that deals with the vulnerability of local communities.
7075-T651 알루미늄합금에서 간단한 변동하중아래에서의 관통균열의 진전거동
李京蘭,辛龍承 서울산업대학교 산업대학원 1996 大學院論文集 Vol.4 No.-
The study covers the examination of through crack growth behavior of 7075-T651 aluminum alloy under stepped variable loading condition. Experiments was carried out by using cantilever bending type specimen with a chevron notch. The stress ratios used in this study are R=0.0-0.1, R=0.3-0.5. The crack growth and crack closure were detected by means of Kikukawa's compliance method with a strain gauge mounted on the backside of each specimen. The results obtained in this study are as follows. When the stepped variable load was applied, the smaller the stress ratio was, the larger the variation of the crack growth rate was. The fatigue crack growth rate data obtained for through cracks were plotted well against the effective stress intensity factor range from 0.8 to 1.7 ??. It was found that the effective stress intensity factor range ratio was related well to the maximum stress intensity factor, stress intensity factor range, and crack length.
신용승,정성균,강진식,김태형 서울産業大學校 2000 논문집 Vol.51 No.2
To improve fatigue properties, usually the shot peening process is used in the industrial world. In order to achieve optimum, repeatable and reliable shot peening process, the important shot peening parameters must be controlled. The first item needed to achieve high quality shot peening is to keep shot balls in a good quality. This paper discusses of shape of commonly used shot ball. Also, discussed is shot ball Shape's effect of Fatigue Life.
신용승,김태형,윤종학,노승남,이철구 서울産業大學校 2002 논문집 Vol.53 No.1
The shot peening process is most often used to improve fatigue properties of metal parts. In order to achieve optimum, repeatable and reliable fatigue enhancement from the shot peening process, the important shot peening parameters must be controlled. In this paper, the optimum shot peening condition is investigated. Rotary bending fatigue test was accomplished to investigate the effects of shot peening on the fatigue strength. Experimental results show that the fatigue strength was tremendously increased by optimum peening.