• Title/Summary/Keyword: Stress path

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Prediction of Stress-strain Behavior for Anisotropic Consolidated Compacted Decomposed Granite Soil (비등방 압밀된 다짐화강풍화토의 응력-변형률 거동 예측)

  • 정진섭;양재혁
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.2
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    • pp.86-95
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    • 2003
  • During this study, constant stress ratio tests with previous compression anisotropic stress history are performed on compacted decomposed granite soil sampled at Iksan, Jeonbuk. Yielding points are determined from stress-strain curves. The shape and characteristics of compression anisotropic yield curves is examined. In addition, the measured value of yielding curve and stress-strain behavior is predicted by Yasufuku's anisotropic constitutive model based on non-associated flow rule. The main results are summarized as follows : 1) Shape of yielding curves shows almost ellipse but asymmetry with respect to stress path during previous consolidation stress. 2) Yasufuku's anisotropic constitutive model is suitable in evaluation of yielding curves on anisotropic consolidated decomposed granite soil. 3) The predicted stress-strain curve shows reasonable agreement to measured behaviours.

Path analysis of the suicidal ideation of Korean adults

  • Yoon, Chae-Min;An, Hye-Gyung
    • International Journal of Advanced Culture Technology
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    • v.7 no.1
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    • pp.103-111
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    • 2019
  • This study attempted to test the path model that can predict Korean adult suicidal ideation. The subjects were 459 adults aged between 19 and 64 who agreed to this study among quota sampled by the population, sex, and region of the metropolitan city. The path model of collected data was estimated using SPSS 24.0 program and AMOS 22.0. The results of the bias-corrected percentile method for verifying the significance of the mediator effect of the final model showed that suicidal attitude, depression, and stress were found to be mediating effects of health status on suicidal ideation. Suicide attitude and stress were found to mediate the effects of health status on depression. And the effect of drinking on depression was mediated by stress. This result is expected to be used as a practical basis for the development of suicide prevention and intervention programs for adults in the future.

Yielding Curve of Isotropic and Anisotropic Consolidated Compacted Weathered Granite Soil (등방 및 비등방 압밀된 다짐풍화화강토의 항복곡선)

  • 정진섭;양재혁
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.1
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    • pp.103-115
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    • 2002
  • During this study, various stress path tests in previous isotropic and anisotropic (compression and tension) stress histories are performed on weathered granite soil sampled at Iksan, Jeonbuk. Yielding points are determined from various stress-strain curves(stress ratio-shear strain, volumetric strain, normalized energy and dissipated total energy curves). The shape and characteristics of isotropic and anisotropic yielding curves are examined. The main results are summarized as follows . 1) Yielding curries defined from stress ratio - normarized energy and dissipated total energy curves show almost perfect ellipse. 2) Directions of plastic strain incremental vector are not perpendicular to yielding curve. 3) Normarized energy and dissipated total energy spread with similar tendency with respect to yielding currie in stress space.

Validation of a Path Model on Adolescents' Suicidal Ideation and Violent Behavior (청소년의 자살사고.폭력행동 경로모형 분석)

  • Park, Hyun-Sook
    • Journal of Korean Academy of Nursing
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    • v.37 no.6
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    • pp.835-843
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    • 2007
  • Purpose: This study examined the fitness of a path model on the relationship among stress, self-esteem, aggression, depression, suicidal ideation, and violent behavior for adolescents. Methods: The subjects consisted of 1,177 adolescents. Data was collected through self-report questionnaires. The data was analyzed by the SPSS and AMOS programs. Results: Stress, self-esteem, aggression, and depression showed a direct effect on suicidal ideation for adolescents, while stress, self-esteem, and aggression showed an indirect effect on suicidal ideation for adolescents. Stress, self-esteem, aggression, and suicidal ideation showed a direct effect on violent behavior for adolescents, while stress, self-esteem, aggression, and depression showed an indirect effect on violent behavior for adolescents. The modified path model of adolescent's suicidal ideation and violent behavior was proven correct. Conclusion: These results suggest that adolescent's suicidal ideation and violent behavior can be decreased by reducing stress, aggression, and depression and increasing self-esteem. Based on the outcomes of this study, it is necessary to design an intervention program that emphasizes reducing stress, aggression, and depression and increasing self-esteem in order to decrease adolescents' suicide ideation and violence.

Validation of a Path Model of Vietnamese Migrant Workers' Occupational Stress (베트남 외국인 근로자의 직무 스트레스 영향요인 경로분석)

  • Jeon, Hye Jeong;Lee, Ga Eon;Yu, JungOk
    • Research in Community and Public Health Nursing
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    • v.29 no.4
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    • pp.404-413
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    • 2018
  • Purpose: The purpose of this study is to construct and verify a path model for the influencing factors on occupational stress of Vietnamese migrant workers in Korea. Methods: Participants were 193 Vietnamese migrant workers recruited from Foreign Workers Support Centers. Data were collected by a self-administered survey with copies of a Questionnaire written in Vietnamese. Data were analyzed with descriptive statistics, Pearson's correlation coefficients and path analysis using SPSS/WIN 23.0 and Amos 20.0 program. Results: Length of residence, homeland friends' and Korean colleagues'supports, and acculturation have been found to have significant direct effects on occupational stress of Vietnamese migrant workers. Meanwhile, Length of residence, homeland friends', Korean colleagues', and their families' supports showed indirect effects on their occupational stress. What had the greatest direct effect on occupational stress of Vietnamese migrant workers was Korean colleagues' support. Conclusion: For reducing occupational stress of Vietnamese migrant workers, it is necessary to strengthen their Korean colleagues' supports in work places. In addition, community organizations should take strategies to enhance homeland friends' supports and to improve acculturation of Vietnamese migrant workers.

A Study on the Fatigue Crack Growth of Cracks in Mechanical Joints (기계적 체결부 균열의 피로균열성장에 관한 연구)

  • 허성필;양원호;정기현
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.1
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    • pp.187-194
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    • 2002
  • It has been reported that cracks in mechanical joints is generally under mixed-mode and there is critical inclined angle at which mode I stress intensity factor becomes maximum. The crack propagates in arbitrary direction and thus the prediction of crack growth path is needed to provide against crack propagation or examine safety. In order to evaluate the fatigue life of cracks in mechanical joints, horizontal crack normal to the applied load and located on minimum cross section is major concern but critical inclined crack must also be considered. In this paper mixed-mode fatigue crack growth test is performed far horizontal crack and critical inclined crack in mechanical joints. Fatigue crack growth path is predicted by maximum tangential stress criterion using stress intensity factor obtained from weight function method, and fatigue crack growth rates of horizontal and inclined crack are compared.

Liquefaction Behaviour and Prediction of Deviator Stress for Unsaturated Silty Sand

  • Lee, Dal-Won
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.7
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    • pp.35-43
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    • 2006
  • This study was carried out to investigate the liquefaction behaviour and predict deviator stress with matric suction, of unsaturated silty sand. The unsaturated soil tests were conducted using a modified triaxial cell and specimens were prepared using the moisture tamping method. The axis translation technique was used to create the desired matric suctions in the specimen. Undrained triaxial compression tests were carried out at matric suction of 0, 2, 5, 10 and 25 kPa. The specimens were sheared to axial strains of about 20% to obtain steady state conditions. The results showed that liquefaction of silty sand only occurs at matric suction of 0 kPa and 2 kPa. The results also show that at matric suctions of 5, 10 and 25 kPa, the resistance to liquefaction increases. As the suction increases, the undrained effective stress path approached the drained stress path. Also, the predicted and measured maximum deviator stress for unsaturated soils using the effective stress concept showed good agreement as matric suction increases. The deviator stress increase is nonlinear as matric suction increases.

Fatigue Strength Assessment of the Cruciform Fillet Welded Joint Using Hot-spot Stress Approach (Hot-spot 응력을 이용한 십자형 필렛 용접재의 피로강도 평가)

  • Seok, Chang-Sung;Kim, Dae-Jin;Koo, Jae-Mean;Seo, Jung-Won;Goo, Byeong-Choon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.11 s.242
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    • pp.1488-1493
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    • 2005
  • In this study, fatigue tests to obtain S-N curves and FE analyses to obtain structural stress concentration factors were conducted for the two types of cruciform fillet welded joints, that is, load-carrying and non load-carrying types. Then we changed the obtained S-N curve of load carrying joint to that based on hot spot stress. As a result, the S-N curve of load carrying joint based on hot-spot stress was almost exactly coincided with that of non load-carrying joint based on nominal stress. So we have conducted that the fatigue strength of a welded joint with different geometry from the non stress distribution along the expected crack path.

Factors Affecting Clinical Practicum Stress of Nursing Students: Using the Lazarus and Folkman's Stress-Coping Model (간호대학생의 임상실습 스트레스 영향요인에 관한 경로분석: Lazarus와 Folkman의 스트레스-대처 모델 기반으로)

  • Kim, Sung Hae;Lee, JuHee;Jang, MiRa
    • Journal of Korean Academy of Nursing
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    • v.49 no.4
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    • pp.437-448
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    • 2019
  • Purpose: This study was conducted to test a path model for the factors related to undergraduate nursing students' clinical practicum stress, based on Lazarus and Folkman's stress-coping model. Methods: This study utilized a path analysis design. A total of 235 undergraduate nursing students participated in this study. The variables in the hypothetical path model consisted of clinical practicum, emotional intelligence, self-efficacy, Nun-chi, and nursing professionalism. We tested the fit of the hypothetical path model using SPSS/WIN 23.0 and AMOS 22.0. Results: The final model fit demonstrated a satisfactory statistical acceptance level: goodness-of-fit-index=.98, adjusted goodness-of-fit-index=.91, comparative fit index=.98, normed fit index=.95, Tucker-Lewis index=.92, and root mean square error of approximation=.06. Self-efficacy (${\beta}=-.22$, p=.003) and Nun-chi behavior (${\beta}=-.17$, p=.024) were reported as significant factors affecting clinical practicum stress, explaining 10.2% of the variance. Nursing professionalism (${\beta}=.20$, p=.006) and self-efficacy (${\beta}=.45$, p<.001) had direct effects on emotional intelligence, explaining 45.9% of the variance. Self-efficacy had indirect effects on Nun-chi understanding (${\beta}=.20$, p<.001) and Nun-chi behavior (${\beta}=.09$, p=.005) through emotional intelligence. Nursing professionalism had indirect effects on Nun-chi understanding (${\beta}=.09$, p=.005) and Nun-chi behavior (${\beta}=.09$, p=.005) through emotional intelligence. The variables for self-efficacy and nursing professionalism explained 29.1% of the Nun-chi understanding and 18.2% of the Nun-chi behavior, respectively. Conclusion: In undergraduate nursing education, it is important to identify and manage factors that affect clinical practicum stress. The findings of this study emphasize the importance of Nun-chi, self-efficacy, emotional intelligence, and nursing professionalism in the development of an educational strategy for undergraduate nursing students.

Comparative Study on Unsaturated Characteristic Curves of Boeun Granite Weathered Soil during Drying and Wetting Paths (건조 및 습윤과정에서 보은 화강암 풍화토의 불포화특성곡선 비교)

  • Song, Young-Suk
    • Journal of the Korean Geotechnical Society
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    • v.32 no.7
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    • pp.15-24
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    • 2016
  • To investigate the unsaturated characteristics of the Boeun granite weathered soil, matric suction and volumetric water content were measured in both drying and wetting paths using Automated Soil-Water Characteristics Curve Apparatus. Based on the measured results, Soil-Water Characteristics Curve was estimated by van Genuchten (1980) model. The relationship between effective degree of saturation and matric suction showed the non-linear curve with S-shape and the hysteresis phenomenon occurred during drying and wetting paths. Suction Stress Characteristics Curve was estimated by the Lu and Likos (2006) model. The suction stress in drying path was constantly maintained and that in wetting path tended to increase when the effective degree of saturation was low. But the suction stress in drying path was larger than that in wetting path at the same degree of saturation when the effective degree of saturation became larger. Meanwhile, Hydraulic Conductivity Function was evaluated by the van Genuchten (1980) model which is one of the parameter estimation methods. The unsaturated hydraulic conductivity decreased with increasing the matric suction, and the decreasing velocity regarding to the matric suction in drying path was larger than that in wetting path.