• Computers and Concrete
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• v.20 no.1
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• pp.85-97
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• 2017

With a special attention to the different stages of a typical loading path travelled in a fluid confined concrete test, this paper introduces a physically consistent model for the stress-strain curve of actively confined normal-strength concrete in the axial direction. The model comprises of the five elements of: (1) a criterion for the peak or failure strength, (2) an equation for the peak strain, (3) a backbone hydrostatic curve, (4) a transient hardening curve linking the point of departure from the hydrostatic curve to the failure point, and finally (5) a set of formulas for the post-peak region. Alongside, relevant details and shortcomings of existing models will be discussed in each part. Finally, the accuracy and efficiency of the proposed model have been verified in a set of simulations which compare well with the experimental results from the literature.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.127-131
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• 2000

The dynamic photoelasticity with the aid of Cranz-Shardin type high speed camera system is utilized to record the dynamically propagating behavior of an interface crack. This paper investigates determined the effects of the hole (existed on the path of the crack propagation) on the crack propagation behavior by comparing the experiment isochromatic fringes to the theoretical stress fields.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.113-119
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• 2005

A crack emanating from an internal electrode or a conducting damage path in ferroelectric ceramic actuators is analyzed. The boundary of the domain switching zone near the edge of the internal electrode in a ceramic multilayer actuator is determined based on the nonlinear electric theory. The stress intensity factor induced by a ferroelectric domain switching under small scale conditions is numerically obtained for flaws of various sizes near the electrode edge. It is found that stress intensity factor near the crack tip depends on the material property of the electrical nonlinearity.

• Advances in materials Research
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• v.8 no.3
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• pp.219-235
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• 2019

This research is devoted to analyzing mechanical-thermal post-buckling behavior of a micro-size beam reinforced with graphene platelets (GPLs) based on geometric imperfection effects. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. The micro-size beam is considered to be perfect (ideal) or imperfect. Buckling mode shape of the micro-size beam has been assumed as geometric imperfection. Modified couple stress theory has been used for describing scale-dependent character of the beam having micro dimension. Via an analytical procedure, post-buckling path of the micro-size beam has been derived. It will be demonstrated that nonlinear buckling characteristics of the micro-size beam are dependent on geometric imperfection amplitude, thermal loading, graphene distribution and couple stress effects.

• Computers and Concrete
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• v.3 no.4
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• pp.261-284
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• 2006

The flexural behaviour of symmetrically reinforced concrete (RC) columns cast of normal- and high-strength concrete under both monotonic and cyclic loading is studied based on an analytical procedure, which employs the actual stress-strain curves and takes into account the stress-path dependence of concrete and steel reinforcement. The analysis is particularly extended into the post-peak stage with large inelastic deformation at various applied axial load level. The effect of axial load on their complete flexural behaviour is then identified based on the results obtained. The axial load is found to have fairly large effect on the flexural behaviour of RC columns under both monotonic and cyclic loading. Such effects are discussed through examination of various aspects including the moment-curvature relationship, moment capacity, flexural ductility, variation of neutral axis depth and steel stress.

• Journal of the Korea Society of Computer and Information
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• v.20 no.11
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• pp.169-174
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• 2015

The study is to clarify the relationship among the positive and negative recognition of stress and physical and psychological abuse and neglect aiming at getting the material. They are to prevent elder abuse at the main care worker for frail and dementia elderly. The degree of fitness to the data where positive and negative recognition of main care worker was located as dependent variable. The casual model in which main care worker was located as independent variable. The degree of fitness of casual model was GFI=0.772, CFI=0.795, RESEA=0.067. Among path coefficient included in the previous model, three of figures going toward three of abuse to the elder were statistically significant.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.2
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• pp.39-46
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• 1990

In this study, the mechanical behavious of a center crack which propagates between two holes in a panel are investigated. It is confirmed experimentally and analytically that a center crack stops and a small crack initiates from holes and propagates to fracture because of the compressive stress arising along the path of the fatigue crack propagation. Futhermore, it is noted that regardless of the configuration of the crack and the structure, Paris' law can be applied to the fatigue crack propagation.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.158-165
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• 2004

Up to now, many crack repair techniques have been developed for inhibiting crack growth in structural components. However, the simplest way for inhibiting crack growth is to apply a indentation at the crack tip or at some distance ahead of the expected crack growth path so as to produce residual compressive stresses that can reduce the effective stresses around the crack tip. In spite of its importance to the aerospace industry, little attention has been devoted to evaluation of the indentation residual stress effect on the fatigue crack initiation life quantitatively. Therefore, in the present work, the magnitude and distribution of the indentation residual stresses were investigated in order to estimate the beneficial effect on fatigue crack initiation by using finite element method. Furthermore, to examine the validity of finite element analysis results, residual stress distribution in the indented specimen was measured by using X-ray diffraction technique, and fatigue crack behavior at fastener hole in aluminum alloy 7075-T6 before and after indentation processes was investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3924-3933
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• 2012

The purpose of this study is to investigate the relationships of social support, marital conflict, self-efficacy, and mothers' parenting stress, which are known as affecting mothers' parenting behaviors of infants a lot. To this study, We used of Korea Institute of Child Care and Education's "Panel Survey of Korea Child; 2009" data. The subjects of mothers of 11~18 months infants 1,467(M=739, F=728). In order to analyze collected data, Person correlation analysis, regression/path analysis were used. The results of the study were as follows: First, the correlations among social support, marital conflict, self-efficacy, and mothers' parenting stress were between -.475 and .401, which are all significant on the level of within p<.01. Of those the correlation between the variable of self-efficacy, and mothers' parenting stress was shown highest as of -.475. Second, the correlations among these variables and mothers' parenting behaviors of infants were between -.484 and .350(all, p<.01). Mothers' parenting stress shows the highest correlations of all, next social support, self-efficacy, marital conflict in order. Third, multiple-correlation of .533, which explains at 28.4 percentage of total variance of the mothers' parenting behaviors. And -.396 in the degree of mothers' parenting stress, which explains at 15.7 percentage of the total variance of the mothers' parenting behaviors, while .223 in social support(4.97%). But marital conflict has not direct effects but indirect effects.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.4
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• pp.518-527
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• 2014

This study examined the effect of media involvement on appearance evaluation, appearance stress, and appearance management behavior. Data were collected from 315 female university students in Daejeon and Chungnam from May to June 2013. Data were analyzed by descriptive statistics, t-test, path analysis using the SPSS-WIN 20.0, AMOS 20.0 program. The results of this study were as follows. First, media involvement were classified into low and high groups. There were significant differences in appearance evaluation by level of involvement. The low group of media involvement indicated a more positive appearance evaluation than the high group. Second, there were significant differences in the appearance management behavior by level of involvement. Third, media involvement directly affected appearance evaluation and appearance management behavior. Appearance evaluation affected appearance stress and appearance management behavior. This study verified the structural relationship of media involvement, appearance stress, and appearance management behavior as outward behavior variables.