• Proceedings of the KWS Conference
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• 2000.04a
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• pp.228-231
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• 2000

Based on the principle of complementary energy an analytical method is developed for determining thermal stress distribution in an thermal barrier coating. This method gives the stress distributions which satisfy the stress-free boundary conditions at the edge. Numerical examples are given in order to verify the method and to investigate the thickness effects of the ZrO$_2$-8wt％Y$_2$O$_3$ top coat on the integrity of thermal barrier coating consisted of IN738LC substrate and MCrAlY bond coat.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.667-670
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• 2004

This study describes a practical method of measurement of the sustained stress in concrete structures. In most cases, the sustained stress was determined by various theoretical calculations. However, the theoretical calculations can not always provide sufficient informations about current stress state having lots of uncertainty. Therefore, the present study proposes a practical measuring method, Partial Sectioning Method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.279-289
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• 2000

Residual stress induced in U-bending and tube-to-tubesheet joint processes of PWR's row-1 heat exchanger tube was measured by X-ray method and Hole-Drilling Method(HDM). Compressive residual stresses(-) at the extrados surface were induced in U-bending, and its maximum value reached -319 MPa in axial direction at the position of $\psi$ = $0^{\circ}$. Tensile residual stresses(+) of $\sigma_{zz}$ = 45 MPa and $\sigma_{\theta\theta}$ = 25 MPa were introduced in the intrados surface at the position of $\psi$ = $0^{\circ}$. Maximum tensile residual stress of 170 MPa was measured at the flank side at the position of $\psi$ = $90^{\circ}$, i.e., at apex region. It was observed that higher stress gradient was generated at the irregular transition regions (ITR). The trend of residual stress induced by U bending process of the tubes was found to be related with the change of ovality. The residual stress induced by the explosive joint method was found to be lower than that by the mechanical roll method. The gradient of residual stress along the expanded tube was highest at the transition region (TR), and the residual stress in circumferential direction was found to be higher than the residual stress in axial direction.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.658-669
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• 2020

Purpose: This study was conducted for Pohang citizens who experienced Pohang earthquake damage. The purpose of this study is to examine how these post-traumatic stress level affect post-traumatic growth and to examine the mediating effects of stress coping on the causal relationship between post-traumatic stress level and post-traumatic growth. Method: The survey was conducted for the citizens who experienced Pohang earthquake, and the survey data were statistically analyzed using the SPSS 25.0 program. Result: Post traumatic stress level has been shown to affect post traumatic growth. In addition, as a result of examining the mediating effect of stress coping method on the relationship among these variables, the problem solving center and the social support method had a mediating effect, but the evasion method did not mediate. Conclusion: The post-traumatic stress level caused by disasters such as earthquakes was found to be able to overcome the obstacle and grow after trauma, as the coping method is problem solving and social support.

• Journal of Families and Better Life
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• v.4 no.1
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• pp.15-31
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• 1986

The purpose of this study is to investigate the relationship between the level of stress recognition of urban housewife and the method of coping, and to explore bow these factors are influenced by socio-demographic variables such as the age of housewife, level of education, status of employment, number of children, durations of marriage, types of family, religion and socio-economic status. The research was conducted on 431 housewives in Seoul in August, 1985. As for the measurement of the instrument, 48 item questionnaire made by investigator was used. The questionnaire was based upon modified and upplemented Holme & Rahe's SRRS and Bell's 18-item Questionnaire to be appropriate to Korean culture. Data were analyzed by percentage, frequency and mean, and verified significant difference by ANOVA and performed Spearman's correlation coefficient. The results of this study are as follows; 1) There is some similarity in distribution of the level of stress recognition of urban housewife. 2) the level of education and the durations of marriage have influence upon the level of stress recognition of urban housewife. In each area, there are differences among groups : age, level of education, durations of marriage, number of children and types of family in the area of education ; age, status of employment, and durations of marriage in the area of health; level of education, durations of marriage, number of children and socio-economic status in the area of finance; status of employment in the area of household work. 3) There are several methods in the method of coping to stress of housewife and the score of long-term coping method appears higher than that of short-term. 4) The level of education, number of children, religion and socio-economic status were variables to have influence on the method level of education, religion and socio- economic status were variables to have influence and in the long-term coping method level of education, number of children, religion, and socio-economic status were to have influence. 5) There is very low positive correlation between the level of stress recognition of urban housewife and the method of coping to stress( ρ=.10, P<.05). 6)In the relation between several variables in socio-demographic variables and the method to coping to stress, the lower the level of stress recognition there are negative correlation (ρ=-.28, P<.01) between religion and the method of coping and also negative correlation (ρ=-.16, P<.05) between number of children and the method of coping. There are positive correlation between socio-economic status and the method of coping.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3058-3067
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• 1996

With increasing use of ceramics/metal bonded joints, It is required to analyze the residual stress distribution and stress singularity at an interface edge for its bonded joints. In this paper, the residual stress distribution and stress singularity index of the ceramics/metal bonded joints were analyzed by using 2-dimensional elastic boundary element method. The variations of residual stress distribution and stress singularity index are studied with changes for the combinations of ceramics/metal bodned joints.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.255-260
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• 2003

Most of the fatigue test were achieved in fully reversed condition that mean stress is zero. But, generally, mean stress can not be zero. This research was achieved the bending fatigue test that changes mean stress to spring steel and was studied relation with the mean stress and the fatigue life. The method to search effect about mean stress was extended S-N graph in two cases. One method was extended S-N graph using modified Miner's rule with considering damage. Another was extended using tendency of S-N graph. The exponential value(${\alpha}$) of mean stress-alternating stress equation is converged between the Goodman's and the Gerber's value even if fatigue life increases.

• Journal of the Korean Wood Science and Technology
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• v.27 no.4
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• pp.51-56
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• 1999

Finite element method was utilized to analyze crack tip stress and displacement field under drying stress case as stepwise loading. Opening mode of single-edge-notched model was employed and analyzed by linear elastic fracture mechanics of plane stress case. The drying stresses were applied as stepwise loads at the boundary elements of the model with 10 steps of time serial. The stress intensity factor($K_I$) for opening mode reached to its maximum just prior to the stress reversal. The $K_I$ from the displacement fields revealed 1.7 times higher than those from stress fields. By comparing the two sets of $K_I$ from displacement and stress fields, single parameter $K_I$ showed its validity to characterize displacement fields around the crack tip front while stress field could not be characterized due to large variations between two sets of data.

• Journal of Welding and Joining
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• v.18 no.5
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• pp.33-40
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• 2000

Fatigue crack propagation life of weld toe crack through residual stress field was estimated with Elber's crack concept. Propagation of weld toe crack is heavily influenced by residual stress caused by welding process, so it is essential to take into account the effect of residual stress on the propagation life of weld toe crack. Fatigue crack at transverse and longitudinal weld toe was studied respectively, which represent typical weld joint in ship structure. Numerical and experimental studies are performed for both cases. Residual stress near weldment was estimated through nonlinear thermo-elasto-plastic finite element method, and residual stress intensity factor with Glinka's weight function method. Effective stress intensity factor was calculated with Newman-Forman-de Koning-Henriksen equation which is based on Dugdale strip yield model in estimating crack closure level U at different stress ratio. Calculated crack propagation life coincided well with experimental results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1218-1226
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• 1993

A method, so called 'successive cracking method,' for measuring residual stresses in a circular disk is proposed. In this method residual stresses are evaluated using a fracture mechanics approach, that is, the strains measured at a point on a edge of the disk as a crack is introduced and extended from the edge are used to deduce the residual stress distribution which existed in the uncracked disk. Through finite element analysis and comparative experiments with generally used sectioning method, the successive cracking method is shown to be valid, simple and effective to measure 2-dimensional residual stress distribution in a circular disk.