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우홍식 동국대학교 경주대학 1995 東國論集 Vol.14 No.-
Fracture is an important consideration when evaluating the integrity of welded structure and a number of methods are currently available for assessing the integrity of welded structure. But they are very expensive, expert methods. So more simple evaluation methods are needed. Therefore, the objective of this study is develope an integrity evaluation computer program on welded structure. Finally, computer program base on FAD was developed the welded stuctures and case studies were performed to evaluate the accuracy. In the results, a computer program base on FAD can b e used as an effective tool for evaluating integrity of welded structures.
우홍식,한지원 東國大學校 1993 東國論叢 Vol.32 No.-
Crack length and closure are monitored simultaneously and countinuously in terms of the testing by a PC-aided unloading elastic compliance technique. The relation between the crack opening stress intensity factor and crack length is determined from the experimental results. The crack opening stress intensity factor of short cracks, K_op, can be predicted from the crack opening stress intensity factor of near threshold of long crack, K_op.L. The growth rate of short cracks at notch root can be predicted from the crack opening stress intensity factor of short cracks, K_op, and the growth equation of long cracks in region Ⅱ.
우홍식 동국대학교 경주대학 1993 東國論集 Vol.12 No.-
The objective of this paper is to investigate the effect of residual stress on the fatigue crack growth behavior in corrosion environments. For this purpose, transverse butt submerged arc welding was performed on SM50A steel plate and CT(compact tension) specimens which loading directions are perpendicular to weld bead were selected. And the environments under which the experiments performed were in air, in pure water and 3.5% NaCl solution. From the experimental results and discussin, in region I, the value of ΔK_th, CF in pure water in similiar to that of 3.5% NaCl solution but they are about 1.6-2.1 times that of air environment. In region Ⅱ, also the fatigue crack growth behavior in pure water is similiar to that of 3.5% NaCl solution. But their behaviors were slower than that of air environment. So it is assumed that the fatigue crack growth behavior was affected by more crack closure phenomenon due to corrosion products than the residual stress.
우홍식,김수용 동국대학교 경주대학 1997 東國論集 Vol.16 No.1
In order to obtain more realistic fracture resistance curve, many researchs are currently underway to introduce new parameter and to quantify the constraint effect. The objective of this paper is to investigate the relationship between the crack tip constraint effect (specimen size, specimen thickness, plane size, crack length ratio and side groove) and the fracture resistance curve. In this paper, fracture toughness tests were performed with various parameters. Test results show that the J-R curve is increased with increase in the plane size and decrease in the crack length and the J-R curve is decreased due to the side groove of specimen. In addition to the effects of the crack length and the plane size on the J-R curve are significant while the effects of specimen thickness and the specimen size on the J-R curve are insignificant.
기업의 안전문화 수준변화와 재해율과의 상관관계: P사 사례연구
박진홍,우홍식 대한안전경영과학회 2022 대한안전경영과학회지 Vol.24 No.4
Safety has once again emerged as a social issue due to the enforcement of the Serious Disasters Punishment Act and the occurrence of major disasters recently. As such, the safety culture related to unsafe human behavior is drawing attention as various discussions about the importance of safety and accident prevention are currently being undertaken. This study aims to determine whether changes in the level of safety culture in companies affect the accident rate. To this end, we targeted three workplaces in the same company in the domestic manufacturing industry, and 2,790 people were surveyed using DNV's Safety Will(ISRS-C version 4.0) for safety culture level diagnosis. The change in safety culture level and accident rate were compared and analyzed after carrying out safety culture level improvement activities for 5 years. As a result, the level of safety culture increased by 5.8 points, an overall improvement of 9.5%, while the total number of accidents decreased by 20%, from 5 to 4, indicating a general decreasing trend in accident occurrence. Results confirmed that the change in the level of safety culture affects the accident rate, and the improvement in the level of safety culture affects a reduction in accidents. Therefore, this study suggests that efforts to improve the level of safety culture within a company can be associated with accident reduction and accident prevention outcomes.
지진하중하의 배관 안정성 평가를 위한 파괴저항 시함에 관한 연구
원종일,우홍식 동국대학교 경주대학 1998 東國論集 Vol.17 No.1
This paper presents the experimental results from cyclic displacement -controlled CT specimens fracture experiments. Seismic loading is consisted of dynamic loading and cyclic loading. According to a study by the International Piping Integrity Research (IPIRG) program, previous pioneering works on cyclic loading on CT specimens showed that reverse cyclic loading was affected by the parameters of load velocity, load ratio, and incremental plastic displacement. The objective of this paper is to investigate the effect of reverse cyclic loading on J-R curves in CT specimens. It is found from experiments that two parameters affect the J-R curves during the reverse cyclic loading. They are the minimum-to-maximum load ratio(R) and the incremental plastic displacement(δ_cycle/δ_i), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance test on CT specimens with varying load ratio and incremental plastic displacement were performed and test results showed that the J-R curves were lowered by the decrease in the load ratio and the decrease in the incremental plastic displacement.
4M 위험성평가 기법을 이용한 앗차사고의 효과적인 발굴기법
서성화 ( Seong Hwa Seo ),원종일 ( Jong Ii Weon ),우홍식 ( Heung Sik Woo ) 한국안전학회(구 한국산업안전학회) 2012 한국안전학회지 Vol.27 No.5
In this study, a new technique for detecting near miss using 4M risk assessment method is suggested. Until now, the safety education with instances of near miss has just been progressed in most industrial settings, without any systematic guideline. By menas of appling 4M risk assessment method, the organized technique, which could effectively manage the fundamental prevention of industrial accident in advance, is developed. The organized technique of near miss-management suggested in this study will take an effective role in basically expanding the application of risk assessment method, as well as in contributing the activity of zero-accident as a safety guideline in hazardous workshops.