• 대한간호학회지
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• 제10권1호
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• pp.57-64
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• 1980

The purpose of the study was to find out the relationship between experienced stressful events and its coping behavior within mentally wellness and illness, and to define the effective coping method under the stressful situation. By doing so, during the period of April, 1978- to March, 1979 the objects of this study were 100 persons who were under the psychiatric facilities in their first hospitalization, and who were registered in psychiatric out patient department in the form general hospitals located at Seoul selected as a experimental group. As a control group 100 persons who never experienced psychiatric treatment who were not under the current medical treatment, and who were tarring appropriate social roles in their community were selected, and in both groups utilized questimaires for Social Readjustment Pating Scale and Coping Scale. This study was tested by X$^2$ examinationand by F-ratio（analysis of variance). Results were as follows : Hypothesis 1. The actually experienced life events were expected to be higher in the experimental group than in the control group, but they did not show the significant difference between the groups.（ p >0.05) Thus hypothesis 1 was rejected. Hypothesis : 2. The stress scores were expected to be higher in the experimental group than in the control group, and also did show the significant difference between the groups ( p< 0.05）. Therefore hypothesis 2 was supported. Hypothesis 3. The non-effective coping behavior were expected to be higher in the experimental group than in the control group, and also did show the significant difference between the two groups(p < 0.001). Also hypothesis 3 was supported. Hypothesis 4 . The higher stress score groups (above 250 LCU ) were expected to utilize non.effective coping method more frequently than in the lower stress score groups (below 249 LCU ), and not only they showed high in utilizing non-effective coping method but also showed high in utililzing effective coping method. Thus hyphothesis 4 was partially supported. (p < 0.001) The following are drawn out based on the result of this study that the stress scores were higher, and more utilized non-effective coping method in the emotionally disturbances than in the emtionally healthies.

• 한국지반공학회논문집
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• 제36권4호
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• pp.5-15
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• 2020

본 논문은 점성토의 응력-변형률 관계를 모사하기 위해 한계 상태 이론을 기반으로 하여 수정한 Modified Cam-Clay 파괴면을 제안한다. 평균유효응력과 von Mises 응력의 공간에서 타원형상의 파괴면을 가지는 Modified Cam-Clay 모델의 경우, 강성 및 발달법칙 미적용시, 비배수 전단조건하에 한계상태 평균유효응력은 선행압밀 평균유효응력의 절반이 되며, 이는 실제 점성토의 거동과 차이가 있다. 본 연구에서는 선행압밀 평균유효응력은 점성토의 압밀이력으로 정량화되고, 한계상태 평균유효응력은 점성토의 현재 간극비로 산정되어, 이 둘간의 비율이 고정되지 않는 찌그러진 형태의 파괴면을 제안한다. 제안된 파괴면을 항복평면으로 가정하고, 비배수 삼축압축 거동을 모사한 결과, 실내 실험 결과와 유사한 결과를 얻을 수 있었다

• Steel and Composite Structures
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• 제4권5호
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• pp.355-365
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• 2004

A new reduction method of residual stress in welding joint is proposed where welded metals are shaken during welding. By an experiment using a small shaker, it can be shown that tensile residual stress near the bead is significantly reduced. Since tensile residual stress on the surface degrades fatigue strength for cumulative damage, the proposed method is effective to reduction of residual stress of welded joints. The effectiveness of the proposed method is demonstrated by the response analysis using one mass model with nonlinear springs.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.245-251
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• 1999

As the crack grows in the residual stress fields, the distribution of the residual stress is changed. In this study, a finite element modeling technique is developed to simulate the redistribution of residual stress due to crack propagation. To certify the accuracy, the crack propagation tests were carried out and tile effective stress intensity factor range was evaluated considering the redistribution of residual stress from the FE analysis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.51-58
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• 2008

The George Massey immersed tunnel passes the Fraser River near Vancouver, Western Canada. In this paper, dynamic analysis of the tunnel on sandy soils was performed using an effective stress constitutive model called UBCSAND. This model is able to calculate pore pressure rise and resulting tunnel deformation due to cyclic loading. Centrifuge tests conducted at RPI are used to verify the model performance. Centrifuge tests consist of 3 models: Model 1 is designed for an original ground condition, Model 2 for a ground improvement by compaction method, Model 3 for a ground improvement by gravel drainage. The results of centrifuge Model 1 are presented and compared with predictions of UBCSAND model. This model well captured the results of centrifuge test and therefore can be used to predict dynamic behavior of similar tunnels or underground structures on sandy soils.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1249-1255
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• 2009

Cord-rubber composites widely used in tires show very complicated mechanical behavior such as nonlinearity and large deformation. Three-phase(cord, rubber and the interface) modeling has been used to analyze the stress distribution in the cord-rubber composites more accurately. In this study, finite element methods were performed using two-dimensional generalized plane strain element and plane strain element to investigate the stress distribution and effective modulus of cord-rubber composites. Neo Hookean model was used for rubber property and several interface properties were assumed for various loading directions. It was found that the interface properties affect the effective modulus and the distributions of shear stress.

• Journal of Welding and Joining
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• 제27권1호
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• pp.90-94
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• 2009

In this study, a series of fatigue test was performed to evaluate the fatigue strength of butt welded specimens. Effective notch stress through finite element analysis was conducted to analyze the fatigue results. As a results, no significant decrease in fatigue strength was observed when backplates were present. The S-N curve that based on effective notch stress appeared a similar fatigue lift to FAT 225 curve without reference to existence of backplates.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.51-54
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• 1996

This paper reports the studies of the inversion layer mobility in p-channel Si MOSFET's under hot-carrier degradated condition. The validity of relationship of hot carrier degradations between the surface effective mobility and field effect mobility and are examined. The effective mobility(${\mu}$$\_$eff/) is derived from the channel conductances, while the field-effect mobility(${\mu}$$\_$FE/) is obtained from the transconductance. The characteristics of mobility curves can be divided into the 3 parts of curves. It was reported that the mobility degradation is due to phonon scattering, coulombic scattering and surface roughness. We are measured the mobility slope in curves with DC-stress [V$\_$g/=-3.1v]. It was found that the mobility(${\mu}$$\_$eff/ and ${\mu}$$\_$FE/) of p-MOSFET's was increased by increasing stress time and decreasing channel length. Because of the increasing stress time and increasing V$\_$g/ is changed oxide reliability and increased vertical field.

• Journal of Welding and Joining
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• 제13권4호
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• pp.155-162
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• 1995

Redistribution of residual stress and its effects during fatigue crack propagates from tensile residual stress region in weldment are investigated. Tests are performed by using welded CCT specimens of structual rolling steel (SS400) and it makes fatigue crack propagate from tensile residual stress region. For this study tension-tension loading type is selected by external loading condition and magnetizing stress indicator is used correctly to measure redistribution of residual stress according to fatigue crack growth and number of loading cycles. From this result, it is proved that redistribution of residual stress is mainly consist of residual stress released by fatigue crack growth. When fatigue crack propagates from tensile residual stress region residual stress are redistributed and it makes fatigue crack growth rate largely increase. Fatigue crack growth rate is low in case of redistributed residual stress compare with initial distributed residual stress.

• Structural Engineering and Mechanics
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• 제63권3호
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• pp.269-280
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• 2017

One major concern that has occupied the mind of the designers is a structural failure as result of stress concentration in the geometrical discontinuities. Understanding the effective parameters contribute to stress concentration and proper selection of these parameters enables the designer get to a reliable design. In the analysis of perforated isotropic and orthotropic plates, the effective parameters on stress distribution around holes include load angle, curvature radius of the corner of the hole, hole orientation and fiber angle for orthotropic materials. This present paper tries to examine the possible effects of these parameters on stress analysis of infinite perforated plates with central quasi-square hole applying grey wolf optimizer (GWO) inspired by the particular leadership hierarchy and hunting behavior of grey wolves in nature, and also the present study tries to introduce general optimum parameters in order to achieve the minimum amount of stress concentration around this type of hole on isotropic and orthotropic plates. The advantages of grey wolf optimizer are stout, flexible, simple, and easy to be enforced. The used analytical solution is the expansion of Lekhnitskii's solution method. Lekhnitskii applied this method for the stress analysis of anisotropic plates containing circular and elliptical holes. Finite element numerical solution is employed to examine the results of present analytical solution. Results represent that by selecting the aforementioned parameters properly, fewer amounts of stress could be achieved around the hole leading to an increase in load-bearing capacity of the structure.