• Title/Summary/Keyword: stress-path

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Analysis of Liquefaction using Stress Path in Silty Sand Grounds (실트질 모래지반의 응력경로를 이용한 액상화 분석)

  • Lee, Song;Kim, Tae-Hwoon;Rhee, Min-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.239-246
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    • 2000
  • It has been generally much fine contents in West Coast of Korea. When cyclic shear stress causing liquefaction was estimated as using cyclic triaxial tests in these grounds, it didn't appear linear relations between deviator stress and confining stress where σ'₃ was more than 150 kpa. Namely, due to no normalization of cyclic shear stress ratio, the errors of this is increased. Therefore, more confining stress is increased, more increment of deviator stress is decreased. So, using linear relations between tanø'/sub d/ of dynamic internal friction angle and CSR where σ'₃ was less than 150 kpa, liquefaction of these grounds was evaluated. Also, as doing detail evaluation which had carried response analysis of earthquake, this appeared good results which was well compatible with empirical methods using N-value of SPT. It was thought that these result evaluated vulnerable liquefaction area more correct than existing methods. Also, characteristics of liquefaction in West Coast grounds was compared with clean sands, with analysis of behavior of pore pressure ratio and axial strain affected by fine contents, as cyclic loading was applied.

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Estimation of Brune's Stress Drops around the Korean Peninsula (한반도 인근 지진의 Brune 응력강하량(파라미터)추정에 대한 고찰)

  • Yun, Kwan-Hee;Park, Dong-Hee;Chang, Chun-Jung
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.70-77
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    • 2006
  • Stress drops of Brune's single-corner ${\omega}^2$ source model were estimated for the earthquakes (2.0$M3.5{\sim}4.0$ and increase up to $M4.5{\sim}5.0$ above which the level of the stress drop could be assumed to be flat or decrease according to whether the rupture process accompanies buried fault or surface rupturing. The converted data of corner frequency and seismic moment were nicely fitted to the relation of $M_0{\propto}f^3$ but show systematically higher corner frequencies for $M_0>10^15$ Nm. This relationship enables systematic evaluation of a scaling relation between magnitude and stress drop. The inverted level of the stress drop is comparable to the recent studies conducted domestic and abroad. A result of lower stress drop estimated by Jun(1991) is supposed to be due to the use of low frequency spectra and existence of two-comer source model around the Korean Peninsula.

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The Influence of Middle·High School Parent's Parenting Stress, Parent Efficacy, Depression and Participation of Parent Education on Child's Life Competency (중·고등학생 학부모의 양육스트레스, 부모효능감, 우울감, 부모교육참여가 자녀의 생활역량에 미치는 영향)

  • Lim, So Jin;Jeon, Se-kyung
    • Journal of Korean Home Economics Education Association
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    • v.28 no.4
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    • pp.123-137
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    • 2016
  • This study's aim is to examine child's life competency that middle high school parents perceive and study the influence of parenting stress, parent efficacy, depression, parent education participation on child's life competency. The study was conducted towards parents who have children attending middle school and high school in Dae-jeon. Official cooperation documents were sent to middle schools and high schools located in Dae-jeon in April, 2013. Surveys were sent by e-mail and a total of 800 replies (excluding those with missing data) collected throughout December 10th to 20th, 2013 were used in the final data analysis. SPSS 23.0 and AMOS 23.0 programs were used for analysis and subject's general characteristics and percentage were analyzed. Pearson's product moment correlation coefficient was used in order to examine the variant's relation. Path model analysis was used to study variant's path and direct and indirect effects of the paths were analyzed as well as the significance. The study's results showed that child life competency and related variants had a high correlation and path model analysis showed that parenting stress, parent efficacy, depression, participation of parent education had a direct and indirect influence on child's life competency. Parenting stress has influence on parent efficacy and depression, but parent education has a different influence on child's life efficacy according to participation. Based on these results, policy suggestions are made throughout family academic perspectives in order to enhance child's life competency.

The Association between Health Teachers' Stress, Burnout, and Self-Efficacy: A Path Analysis Approach (보건교사의 직무 스트레스와 소진 및 자기 효능감에 대한 구조모형: 경로분석)

  • Lee, Mi-Joon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.317-325
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    • 2020
  • Using a structural model, this study aims to verify the association between job stress, burnout, and self-efficacy levels of health teachers responsible for school health. Structured questionnaires were administered to 814 health teachers, and validated through Structural Equation Modeling (SEM). The study results show that job stress of the health teacher was 2.9±0.64 and burnout was 2.6±0.52, which was slightly lower than the median of the Likert 5-point scale, while self-efficacy was 4.1±0.51. Various sub-factors contributed to the scores: 'student and family' and 'peer teacher's perception' were high for job stress, while 'work in charge' was high for burnout. Job stress of health teachers resulted in increased burnout and decreased self-efficacy. Furthermore, increased burnout significantly decreased self-efficacy. Hence, job stress affected burnout, and burnout affected self-efficacy. Our data clearly demonstrates that job stress is very important to reduce burnout of health teachers and increase their self-efficacy. Therefore, various efforts are required to lower job stress. This study will help to establish new policies and practical improvement plans to reduce job stress and exhaustion of health teachers, and consequently increase their self-efficacy.

Stress and psychological Distress as Determinants of Parenting Practices among Poor Single Mothers (빈곤층 편모의 스트레스가 부모역할 수행에 미치는 영향 :심리적 디스트레스의 매개역할을 중심으로)

  • 한경혜
    • Journal of Families and Better Life
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    • v.14 no.4
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    • pp.263-276
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    • 1996
  • The purpose of this study is to explore various environmental factors that explain parenting practices. Those factors considered are stress and characteristics of single-mother/child together with psychological distress experienced by the single mother. A total of 285 poor single mothers with a child attending elementary school or junior high school completed a structured questionaire. The relationships among the variables were analyzed by the path analysis. The results showed that poor single mothers rely on affectiv $e^portive involvement more frequently then punitive/inconsistent discipline. It is also confirmed that the enviromental factors such as financial stress living environmental stress and job status play important roles in determining the quality of parenting practices with the mediating role of psychological distress.ss.

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Nonlinear analysis of the influence of increments amounts and history load on soil response

  • Ivandic, Kreso;Soldo, Bozo
    • Structural Engineering and Mechanics
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    • v.33 no.1
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    • pp.67-77
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    • 2009
  • The soil response calculation is described, by which, threw the fictive path of stress, the stress-deformation diagrams are determined, considering the nonlinear soil behavior. The calculation are lead incrementally, by which is shown that in the presented soil model (modified Cam Clay), considering the influence of overconsolidated soil pressure OCR, the number of calculation steps may, but not necessarily, have a sufficient influence on the value of failure load and definite soil deformation. The simplicity and the practicalness of the procedure, the enables modeling the complex relations in soil.

A Study on Fatigue Crack Propagation Analysis and Fatigue Strength Evaluation for Bulk Carrier (살물선의 피로균열 전파해석과 피로강도 평가에 대한 연구)

  • 엄동석;김충희
    • Journal of Welding and Joining
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    • v.11 no.4
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    • pp.112-124
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    • 1993
  • It has been reported that fatigue damage sometimes occurred at the stress concentrated and dynamic loaded structural members of bulk carrier. In this paper, studies on fatigue strength of hull structures are reviewed, and the program for evaluating fatigue strength is developed. And the fatigue crack initiation and propagation on the end part of cargo hold frame of bulk carrier were calculated by FEM stress analysis and the fatigue strength evaluation program. These method can be applied not only to the crack initiation life but also to crack propagation life for the hull structural members at the hull design stage and be effective as the guideline to prevent the crack initiation or to estimate the fatigue strength for repairing of the fatigue damaged structures of real ships.

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Calculation of Stress Intensity Factor in 2-D Using $J_k$-Integral for a Rectilinear Elastic Anisotropic Body (2차원 선형 탄성 이방성 재료에서 $J_k$-적분을 이용한 응력확대계수 계산)

  • An, Deuk-Man;Choi, Chang-Yeon
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.7
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    • pp.134-142
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    • 2001
  • The integrals $J_k$(k=1,2) in the rectilinear anisotropis body in 2-D were determined using Lekhnitskii formalism. The relationship between $J_k$ and stress intensity factors are implified by the important equation between elastic compliance. The numerical evaluation of stress intensity factor for the single edge crack in mixed mode is determined by superposing known exact solutions.

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Fracture Analysis of Welded Plates using the J-integral (J-적분을 이용한 용접구조물의 파괴해석)

  • 심용래
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.173-179
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    • 1996
  • Study of weldment fracture behavior includes thermal analysis, residual stress analysis, and fracture analysis. The J-integral loses its path-independency in a residual stress field. Therefore, it is necessary to develop a program to calculate the J-integral in a welded plate. In this study, theoretical formulation and program were developed for the evaluation of the J-integral at the crack tip of weldments. To verify equations and program, welded thin plate and thick plate were used to calculate residual stress and the J-integral.

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A Strength Analysis of Welded Plates Using the J-integral (J-적분을 이용한 용접부 강도 해석)

  • 이민호;양영수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.326-329
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    • 2000
  • Study of Weldment fracture behavior mcludes thermal analysis, residual stress analysis, and fracture analysis The 1-integral loses its path-independency in a res~dual stress field Therefore, it id necessary to develop a program to calculate the J-integral in a welded plate. m this study, theoretical formulation and program were developed for the evaluation of the 1-integral at the crack tip o i weldments. To verify equations and program, welded thin plate and thick plate were used to calculate residual stress and the J-integral.

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