• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.25-30
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• 2004

The magnitude of constraint effect $A_{2}$ values were experimentally estimated using displacement according to measuring positions on the non-linear elastic plastic fracture toughness estimate. For 25.4 mm thickness SS400 steel CT specimen, constraint effect $A_{2}$ values we re dependent on specimen configuration and on measured displacement near crack front. Commonly, Estimating constraint effect $A_{2}$ measuring position for displacement should be existed inside plastic region. Therefore, the ${\delta}_{5}$ method was not reliable for evaluation of constraint effect $A_{2}$ values because measuring position for displacement is in elastic region at crack growth initiation in this paper.

• 한국재난정보학회 논문집
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• 제7권2호
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• pp.161-171
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• 2011

민간경호원의 여가활동 참여유형 및 여가제약이 삶의 질에 미치는 영향을 규명하기 위해 서울, 경기 지역의 민간 경호업체에 종사하는 만 20세 이상의 경호원 200명을 모집단으로 편의표본추출법을 사용한 조사를 실시하였다. 수집된 자료는 SPSS/WIN 17.0V 프로그램을 이용하여 빈도분석과 다중회귀분석을 실시하였다. 연구결과, 여가참여유형중 정(+)적인 영향을 미친 것으로 스포츠유형은 시간제약, 취미유형은 시간과 비용제약, 관람유형은 개인적제약과 사회적 제약 및 관광유형, 놀이유형은 개인적 제약요인이었다. 반면 사교형 참여유형은 개인적 제약요인과 취미요인 및 가족관계질과 사회관계질 여가관계질에 정(+)적인 영향을 미쳤다. 하지만 관람형 참여유형과 놀이관련 참여유형은 가족관계 질에 부(-)적인 영향을 미친 반면 관광관련 유형은 사회관계질에 정(+)적인 영향을 여가관계질에 부(-)적인 영향을 미쳤다. 마지막으로 민간경호원의 여가제약요인 중 시간제약요인은 가족관계질과 비용제약요인은 삶의 질 전체요인에 정(+)적인 영향력을 발휘했다. 반면 개인적, 가족적 제약요인은 여가관계질 요인에 부(-)적인 영향을 미쳤고 사회적 제약요인은 가족관계질에는 정(+)적인 영향을 여가관계 질에는 부(-)적인 영향을 미쳤다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권4호
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• pp.533-538
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• 2009

The magnitude of constraint effect $A_2$ values on the non-linear elastic plastic fracture toughness was experimentally estimated by using displacement at various measuring positions near crack tip. Constraint effect $A_2$ value was dependent on specimen configuration and on the measured displacement near crack front. The crack tip opening displacement in the vicinity of the crack tip front should be estimated within plastic region when appropriately constraint effect was calculated. It was found that the magnitude of constrain effect |$A_2$| is below 8.0 at the crack tip. But an appropriate location to measure the effective constraint effects $A_2$ at the critical value of J that crack initiation is characterizable by is r = 2mm and ${\theta}=90^{\circ}$ away from original crack tip, and the constraint effect |$A_2$| estimated is 5.3.

• 한국압력기기공학회 논문집
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• 제15권1호
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• pp.71-76
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• 2019

Actual stress distributions in the nozzle of a pressure vessel may not be in plane strain condition, implying that the crack-tip constraint condition may be relaxed in the nozzle. In this paper, a methodology for evaluating the fracture toughness of the ASME Code is presented considering the relaxation of the constraint effect in the nozzle of the reactor pressure vessel. The crack-tip constraint effect is quantified by the T-stress. The equation, which represent the relation between the fracture toughness in the lower constraint condition and the plane strain fracture toughness, is derived using the T-stress. This equation is similar to the method for evaluating the fracture toughness of the Master Curve for low constraint conditions. As a result of evaluating the fracture toughness considering the constraint effect in the reactor inlet, outlet and direct injection nozzles using the proposed equation, it was confirmed that the fracture toughness in the nozzles is higher than the plane strain fracture toughness. Applying the proposed evaluation methodology, it is possible to reflect the relaxation of the constraint effect in the nozzles of the reactor pressure vessel, therefore, the safe operation area on the pressure-temperature limit curve can be prevented from being excessively limited.

• 경영과정보연구
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• 제35권1호
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• pp.69-84
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• 2016

본 연구는 목적인 소비자의 구전제약요인과 구전과의 관계를 여가제약 이론을 바탕으로 구전제약요인들과 이에 대한 협상노력이 몰입과 구전의도와 관계를 살펴보기 위한 연구모형을 설정하였으며, 변수들 간의 관계를 실증적으로 검증하였으며, 연구결과를 요약하면 다음과 같다. 가설을 검증한 결과 2개의 가설(가설 1, 가설 5)을 제외하고 모든 가설이 채택되었다. 이에 대한 구체적인 결과는 다음과 같다. 첫 번째, 내재적제약이 구전제약 요인이 구전제약 협상노력에 미치는 영향을 살펴보면 다음과 같다. 대인적제약과 구조적제약은 구전제약 협상노력에 정(+)의 영향을 미치고 있으며, 내재적 제약의 경우 음(-)의 영향을 미치는 것으로 나타나 가설검증에서는 기각하였지만, 통계적으로는 유의한 것으로 나타났다. 두 번째, 구전제약 협상노력과 몰입 그리고 구전과의 구조적인 관계를 살펴보면 다음과 같다. 구전제약 협상노력은 몰입에 정(+)의 영향을 미치고 있지만, 구전에는 통계적으로 유의하지 않는 것으로 나타났다. 마지막으로 몰입은 구전에 정(+)의 영향을 미치는 것으로 나타나 매개역할을 하고 있음을 알 수 있다. 본 연구의 결과는 구전제약요인과 소비자의 몰입과 구전에 대한 종합적인 이해와 함께 중요한 이론적, 실무적 시사점을 제공할 것으로 기대된다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.91-92
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• 2006

For the CT specimen of 25.4mm thickness SS400 steel, the fracture toughness and the magnitude of constraint effect, $A_2$ on the non-linear elastoplastic fracture behaviors were experimentally estimated by crack tip opening displacement. In order to estimate constraint effect, displacement measurement position near crack front should be the existed within plastic region. But it is found that the displacement measurement positions by the ${\delta}_5$ method are in elastic region at crack growth initiation. Hence the estimate of constraint effect, $A_2$ by the ${\delta}_5$ method was not reliable.

• 대한금속재료학회지
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• 제46권6호
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• pp.345-350
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• 2008

The magnitude of constraint effect $A_2$ value was experimentally estimated by using crack tip opening displacement(CTOD) between elastic and plastic regions near crack tip front for CT specimen with $25.4t{\ss}{\AE}$ SS400 steel. The constraint effect, $A_2$ was dependent on specimen configuration and on the measured positions of CTOD near crack front. $A_2$ should be estimated using the opening displacement calculated within crack front plastic region. If not, it's not reliable to evaluate of constraint effect at crack growth initiation in this paper.

• 가족자원경영과 정책
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• 제9권1호
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• pp.59-73
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• 2005

The purpose of this study was to understand which factors affect on the leisure constraint and leisure attitude of workers, to observe how the factors of leisure constraints affect on the leisure attitude. The subjects of this study were 267 urban workers who are older than 20 years old and resident in Seoul. The periods of this study was from November 15 to December 5. The modified versions of leisure constraint scale and leisure attitude scale were utilized for this study. The results of this study are as follows : First, as a result to compare the average of leisure constraint factors, intrapersonal constraint, which are individual mental status as interest, self-consciousness, uneasiness et at., was founded generally less than interpersonal constraints as personal relationship for leisure activity, or structural constraints as financial, time, information et at., Secondly, it was found that interpersonal constraint was statistically different in age, and that structural constraint was statistically different in sex, education, health status, marital status, income, and career. Thirdly, there were statistically different in cognitive leisure attitude, feeling leisure attitude, and behavioral leisure attitude according to the average monthly income and career. But, it was found that marital status and the five-day workweek system were not statistically different in 3 leisure attitude factors. Finally, 3 leisure constraint factors(intrapersonal, interpersonal, structural) had statistically significant effect on cognitive leisure attitude. Also, intrapersonal leisure constraint and interpersonal leisure constraint had statistically significant effect on feeling leisure attitude and behavioral leisure attitude

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1726-1746
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• 2022

This paper presents fracture mechanics analysis results for various cracks located at pressurized water reactor pressure vessel nozzle crotch corners taking into consideration constraint effect. Technical documents such as the ASME B&PV Code, Sec.XI were reviewed and then a fracture mechanics analysis procedure was proposed for structural integrity assessment of various nozzle crotch corner cracks under normal operation conditions considering the constraint effect. Linear elastic fracture mechanics analysis was performed by conducting finite element analysis with the proposed analysis procedure. Based on the evaluation results, elastic-plastic fracture mechanics analysis taking into account the constraint effect was performed only for the axial surface crack of the reactor pressure vessel outlet nozzle with cladding. The fracture mechanics analysis result shows that only the axial surface crack in the reactor pressure vessel outlet nozzle has the stress intensity factor exceeding the low bound of upper-shelf fracture toughness irrespectively of considering the constraint effect. It is confirmed that the J-integral for the axial crack of the outlet nozzle does not exceed the ductile crack initiation toughness. Hence, it can be ensured that the structural integrity of all the cracks is maintained during the normal operation.

• 대한기계학회논문집A
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• 제26권1호
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• pp.105-112
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• 2002

In recent years, the integrity of reactor Pressure Vessel(RPV) under pressurized thermal shock (PTS) accident has been treated as one of the most critical issues. Under PTS condition, the combination of thermal and mechanical stress by steep temperature gradient and internal pressure causes considerably high tensile stress at the inside of RPV wall. As a result, cracks on inner surface of RPV may experience elastic-plastic behavior which can be characterized by J-integral. In such a case, however, J-integral may possibly lose its vapidity due to the constraint effect. The degree of constraint effect is influenced by the loading mode, crack geometry and material properties. In this paper, in order to investigate the effect of clad thickness and crack geometry on constraint effect, three dimensional finite element analyses were performed for various surface cracks. Total of 27 crack geometries were analyzed and results were presented by a two-parameter characterization based on the J-integral and the f-stress.