• Computational Structural Engineering
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• v.8 no.4
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• pp.137-148
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• 1995

A new path independent contour integral formulus for the distinct calculation of mode I stress intensity factors in two dimensional linear elastic fracture mechanics problems is presented. This method is based on p-convergence concepts and can be easily appended to existing finite element computer codes. In this study, the stress state at crack tip has been investigated and the path independence of J-integral values has been tested with respect to different contours expressed by normalized distance apart from the crack tip. Numerical results by p-convergence for the problems such as centrally cracked panels, single and double edged cracks in rectangular panels have been compared with those by the conventional h-convergence. The comparison demonstrates the accuracy and stability of the proposed method.

• Interaction and multiscale mechanics
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• v.2 no.1
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• pp.31-44
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• 2009

While the classical theory of Griffith is the foundation of modern understanding of brittle fracture, it has a number of significant shortcomings: Griffith theory does not predict crack initiation and path and it suffers from the presence of unphysical stress singularities. In 1998, Francfort and Marigo presented an energy functional minimization method, where the crack (or its absence) as well as its path are part of the problem's solution. The energy functionals act on spaces of functions of bounded variations, where the cracks are related to the discontinuity sets of such functions. The new model presented here uses modified energy functionals to account for molecular interactions in the vicinity of crack tips, resulting in Barenblatt cohesive forces, such that the model becomes free of stress singularities. This is done in a physically consistent way using recently published concepts of Sinclair. Here, for the consistency of the model, it becomes necessary to allow for crack reversibility and to consider local minimizers of the energy functionals. The latter is achieved by introducing different time scales. The model is solved in its global as well as in its local version for a simple one-dimensional example, showing that local minimization is necessary to yield a physically reasonable result.

• Journal of Ocean Engineering and Technology
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• v.1 no.2
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• pp.113-122
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• 1987

Ships and offshore strrctures are exposed to the corrosive surroundings, and the extablishment of the design criteria and the elucidation on the influence by this environment are requested to maintain the safety and to demonstrate the function of the structure. In this paper, the fatigue-crack-growth behavior on the compact tension specimens of quenched, tempered HT80 grade steels and RA36 high tensile steels having a single edge fatigue cracked notch respectively, were investigated under the repeated tensile stress with constant stroke in sea water for the welded parts by shielded metal arc welding. Main results obtained are summerized as follows; 1. The fatigue-crack-growth rates da/dN in sea water appeared to be greater behavior than those in air environment at the same stress intensisy factor range $\DeltaK$. 2. The correlation data of da/dN$\DeltaK$ of the two kinds of high tensile steels in sea water showed no great difference, however, the correlation data of da/dN$\DeltaK/\sigma_y$($\sigma_y$ stands for yield strength of the material) showed that the fatigue-crack-growth behavior of RA36 plate is affected by active path corrosion(APC) mechanism, while that of HT80 grade plate is mainly affected by hydrogen embrittlement mechanism.

• Journal of the Korean Dietetic Association
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• v.25 no.4
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• pp.257-268
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• 2019

This study provides basic data on how stress impacts the processed convenience foods purchase attitudes and the selection attributes of housewives. The stress consists of 3 factors, which were housework stress, family relation stress and economic stress. The processed convenience food purchase attitude consisted of 2 factors, which were peripheral influence purchase and conviction purchase. The processed convenience food selection attribute consisted of 4 factors, which were quality, convenience, packaging and price. Factor loading confirmation and reliability test were conducted, and the reliability was confirmed with Cronbach's alpha coefficients for all the factors exceeding 0.5. The high stress levels showed significantly high stress factors of housework, family relations and economic stress (P<0.001). The high stress group was shown to make purchases by recognizing peripheral influences (P<0.01). When the selection properties of processed convenience foods depending on different stress levels were examined, it was revealed that among the three groups, the low stress group least considered the price aspect (P<0.01). After deducting the factors, AMOS (Analysis of Moment Structure) was used to conduct the confirmatory factor analysis for verifying validity. The structural equation model was used to determine the path coefficient. From the processed convenience foods purchase attitude, the peripheral influence purchase had significantly positive (+) effects on convenience (P<0.05). Also, conviction purchase was shown to have significantly positive (+) effects on quality (P<0.05). Housework and family relation stress were shown to have negative (-) effects on processed convenience foods selection attribute, and economic stress was shown to have positive (+) effects, although no significant relationships were revealed.

• Korean Journal of Veterinary Research
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• v.13 no.2
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• pp.119-129
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• 1973

A hypothesis that is a stress condition in animal may cause either enhancement or reduction of the host resistance against microbial infection was experimentally studied. Among of many processes for stress formation an experimental electrization in mice was devised, on the bases of blood picture analysis, and studied the effect of experimental electrization of mice on E. coll infection. The results obtained were as follows. 1. Electrization with ordinary current, A. C. 60 cps., on the path of symmetrical line of both posterior limbs at 20 to 100 volts (less than 10 mA) for 15 to 30 seconds was able to induce a stress reaction in blood pattern without showing any dangers of electrocution, electric burns and other residual signs, and no correlation between blood pattern of the reaction and an amount of current between 20 to 100 volts was observed. As the electrodes, two of 21 gauge hypodermic needles were used, when the electrization each of them were inserted into the center of toe tissue of the both legs. 2. Serum protein fractions following the experimental electrization showed a tendency of a low A/G ratio and a high value of ${\alpha}$-globulin. 3. In the studies on the effect of electrical stress on the pathogenesis of E. coli in mice, a group in which a simultaneous electrization and infection, and a group infected two hours after electrization showed 80 per cent mortality. On the other hand, infection after 20 hours electrization and control groups showed their mortality of 40 and 60 per cent respectively.

• Geotechnical Engineering
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• v.14 no.4
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• pp.129-140
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• 1998

Elasto-plastic finite element analysis of geotechnical boundary value problems necessitate the stress integration for the known strain increments. For the elasto-plastic constitutive model, the stress integration is generally achieved by numerical schemes, because analytical integration is impossible for general strain path. In this case, the accuracy of numerical stress integration has an important role on the overall accuracy of nonlinear finite element solution. In this study, the Sloan's substepping method which is one of explicit integration methods has been adopted and iris applicability has been checked. The unstability and inaccuracy of ifs results initiated from initial stress level were revealed. So. a new modified numerical integration method which employs the basic concept of modified Euler scheme for error control is proposed and accuracy and stability of the solutions are confirmed by triaxial test simulation.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.2
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• pp.265-272
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• 2013

Purpose: This study was done to identify the effects and relationships of humor, job satisfaction, job stress and intent to turnover for nurses and suggest a theoretical structural path diagram among the variables. Methods: Data were collected at 6 hospitals located in Seoul, and Gyeonggi Province, from June to September, 2010. Participants were 275 nurses. Data were analyzed using Amos 19.0 for Structural Equation Modeling. Results: Humor had significant effects on job satisfaction (${\beta}$=.15, t=2.29, p=.022) and indirect effects on the intent to turnover in this model ($X^2$=44.18, df=23, RMSEA=0.05, TLI=0.97). But humor did not affect job stress unlike results of previous studies (t=-.02, p=.771). Conclusion: Humor may not affect job stress under the very stressful conditions of the health care environment. The model showed the effect of humor contributed to increases in job satisfaction but did not decrease job stress. Higher levels of job satisfaction could decrease the intent to turnover. Consequently, humor would be helpful in increasing job satisfaction to diminish nurse turnover. Further studies are suggested to investigate causal relationships among humor, burnout, and other emotional and organizational variables.

• Korean Journal of Materials Research
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• v.25 no.12
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• pp.690-693
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• 2015

Fatigue crack growth experiments were carried out on a 304 L stainless steel compact-tension(CT) specimen under load control mode. Neutron diffraction was employed to quantitatively measure the residual strains/stresses and the evolution of stress fields in the vicinity of a propagating fatigue-crack tip. Three principal stress components (i.e. crack growth, crack opening, and through-thickness direction stresses) were examined in-situ under loading as a function of distance from the crack tip along the crack-propagation path. The stress/strain fields, measured both at the mid-thickness and near the surface of the CT specimen, were compared. The results show that much higher compressive residual stress fields developed in front of the crack tip near the surface than developed at the mid-thickness area. The change of the stresses ahead of the crack tip under loading is more significant at the mid-thickness area than it is near the surface.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.3
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• pp.372-381
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• 2013

Purpose: The purposes of this study were to analyze the mediating effects of empowerment, job stress, organizational commitment and relation-oriented nursing organization culture on turnover intention of clinical nurses. Methods: Participants selected for the final analysis were 382 nurses working in 4 general hospitals. Data were analyzed through descriptive statistics Pearson correlation analysis (SPSS/WIN 17.0), and Path analysis (AMOS 18.0). Results: The study results are as follows: relation-oriented nursing organizational culture had no direct effect but had an indirect effect on nurses' turnover intention through empowerment, job stress, and organizational commitment, while job stress and organizational commitment had direct effects on turnover intention. The results also showed that empowerment had strong effect on organizational commitment, but job stress had very weak effect. Empowerment had an effect on turnover intention. Conclusion: These results indicate that establishment of relation-oriented nursing organization culture is imperative if clinical nurses' turnover intention is to be decreased.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.18-27
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• 1996

The feasibility of using stress-wave technique in the transverse direction for the assessment of early stages of decay was investigated using compression test specimens having different annual ring orientations subjected to decay by Tyromyces palustris for various time intervals. Decay detection, quantitative assessment of decay, and the prediction of residual strength of decayed wood with less than five percent weight loss can be feasible using stress-wave parameters (wave velocity, wave impedance, and stress-wave elasticity) and their percent reduction due to decay, measured by stress-wave technique in the transverse direction. The use of stress-wave technique in the transverse direction for the application of this technique to structural members in service is desirable, when considering the easiness of attachment of accelerometers of stress-wave measuring device on the surface of members and also accurate detection of localized decayed areas. In stress-wave technique in the transverse direction, stress-wave parameters measured were different according to the angles between wave propagation path and annual ring, due to the anisotropy of wood structure. Therefore, it is recommended to use percent reduction in stress-wave parameters instead of stress-wave parameters. This evaluation method using percent reduction in stress-wave parameters is ideal when it is impossible to observe annual ring orientation on the transverse surface of wood.