• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.8 s.239
• /
• pp.1078-1084
• /
• 2005

The relationship between fatigue crack opening behavior and the reversed plastic zone sizes is studied. An elastic-plastic finite element analysis (FEA) is performed to examine the opening behavior of fatigue crack, where the contact elements are used in the mesh of the track tip area. The smaller element size than reversed plastic zone size is used fer evaluating the distribution of reversed plastic zone. In the author's previous results the FEA could predict the crack opening level, which crack tip elements were in proportion to the theoretical reversed plastic zone size. It is found that the calculated reversed plastic zone size is related to the theoretical reversed plastic zone size and crack opening level. The calculated reversed plastic zone sizes are almost equal to the reversed plastic zone considering crack opening level obtained by experimental results. It can be possible to predict the crack opening level from the reversed plastic zone size calculated by finite element method. We find that the experimental crack opening levels correspond with the opening values of contact nodes on the calculated reversed plastic zone of finite element simulation.

• Fashion & Textile Research Journal
• /
• v.19 no.1
• /
• pp.30-39
• /
• 2017

This study examines on the relationship of appearance instrumentality and appearance-related variables (appearance concern, appearance management behavior) of college students. Questionnaires were administered to 313 college students living in Daegu. The SPSS 20.0 package was utilized for data analysis which included frequency analysis, Cronbach's ${\alpha}$, factor analysis, cluster analysis, cross tabulation analysis and t-test. Three factors of appearance instrumentality(love relationship, social achievement, interpersonal relationship), two groups of appearance concern(high, low) and five factors of appearance management behavior(skin care/cosmetics usage behavior, body management behavior, plastic surgery behavior, hair management behavior, fashion management behavior) were utilized for the problem analysis of the study. The results of this study were: First, there was no significant differences in the appearance concern group according to appearance instrumentality. Second, appearance instrumentality had a significant differences on appearance management behavior. Social achievement showed a significant differences in plastic surgery behavior. And love relationship showed a significant differences on plastic surgery behavior and fashion management behavior. Third, the appearance concern had a significant differences on all of appearance management behavior. High group of appearance concern showed a higher average than low group of appearance concern in fashion management behavior, skin care/cosmetics usage behavior, hair management behavior, plastic surgery behavior, body management behavior.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.2
• /
• pp.39-44
• /
• 2011

Plastic gradient from geometrically necessary dislocation(GND) can strongly affect micro-scale plastic behavior of polycrystalline solids. In this research, mechanical behavior of polycrystalline solid is investigated using the finite element method incorporating plastic gradient from GND effect. Gradient hardness coefficient and material length parameter are used to evaluate the effect of the plastic gradient on the behavior of materials. Sensitivity of the modeling parameters on the plastic gradient from GND is presented and effects of plastic gradient and material parameters on the behavior of single crystal inside a polycrystalline aggregate are investigated. It is confirmed that the plastic gradient from GND amplifies hardening response of polycrystals and affects single crystal behavior embedded in polycrystalline solids.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.5
• /
• pp.1158-1167
• /
• 1995

In this study, the dynamic instabilities of a beam, subjected to periodic short impulsive loading, are investigated using simple 2-DoF beam model. The behaviors of beam model whose axial motions are constrained are studied for the case of elastic and elastic-plastic behavior. In the case of elastic behavior, the chaotic responses due to the periodic pulse are identified, and the characteristics of the behavior are analysed by investigating the fractal attractors in the Poincare map. The short-term and long-term responses of the beam are unpredictable because of the extreme sensitivities to parameters, a hallmark of chaotic response. In the case of elastic-plastic behavior, the responses are governed by the plastic strains which occur continuously and irregularly as time increases. Thus the characteristics of the response behavior change continuously due to the plastic strain increments, and are unpredictable as well as the elastic case.

• Korean Journal of Human Ecology
• /
• v.20 no.3
• /
• pp.625-636
• /
• 2011

The purpose of this study was to investigate the effects of mass media and personal factors on attitudes towards plastic surgery and plastic surgery behavior. For this study the personal factors included concern for appearance, self-esteem, and body satisfaction. Subjects were 472 college students in Ulsan. The results showed that favorable attitudes towards plastic surgery were a little higher than the median, meaning that the respondents had a slightly positive attitude towards plastic surgery, and only 20% of the respondents had had an experience with plastic surgery. A multiple regression analysis was computed and indicated that a more positive attitudes towards plastic surgery was related to high levels of concern for appearance, more time watching TV, a higher household income, and being a female student, in terms of gender. The results of logit analysis indicated that a more positive attitude towards plastic surgery and being a female student related to a higher probability of having had plastic surgery.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.7
• /
• pp.667-672
• /
• 2004

An experimental study has been carried out to investigate the frosting behavior on the plate of thermally conductive plastic (PBT based resin) by comparing it with those of aluminum and some plastic test specimens (PTFE based resin). It is found that the frosting behavior of plastic specimens with 1 mm thickness shows similar trend to that of aluminum except PTFE. The properties of frost formed on the specimens are found to be affected by both thermal conductivity and surface characteristics of the materials. The results indicate that the heat and mass transfer rates of PBT resin are almost equivalent to those of aluminum.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.14-17
• /
• 1999

The wrinkling behavior of a thin sheet with perfect geometry is a kind of compressive instability. The compressive instability is influenced by many factors such as stress state mechanical properties of the sheet material geometry of the body contact conditions and plastic anisotropy. The analysis of compressive instability in plastically deforming body is difficult considering all the factors because the effects of the factors are very complex and the instability behavior may show wide variation for small deviation of the factors. In this study the bifurcation theory is introduced for the finite element analysis of puckering initiation and growth of a thin sheet with perfect geometry. All the above mentioned analysis and the post-bifurcation behavior is analyzed by introducing the branching scheme proposed by Riks. The finite element formulation is based on the incremental deformation theory and elastic-plastic material modeling. in order to investigate the effect of plastic anisotropy on the compressive instability a square plate that is subjected to compression in one direction and tension in the other direction is analyzed by the above-mentionedfinite element analysis. The critical stress ratios above which the buckling does not take place are found for various plastic anisotropic modeling method and discussed. Finally the effect of plastic anisotropy on the puckering behavior in the spherical cup deep drawing process is investigated.

• The Journal of Korean Academy of Prosthodontics
• /
• v.37 no.5
• /
• pp.672-686
• /
• 1999

The purpose of this study was to compare the casting problem and corrosion behavior in two types of HL Hexed abutments of the Steri-Oss system ; gold/plastic coping and gold coping. The anodic Polarization behavior, the galvanic corrosion between abutments and Type III gold alloys, before and after casting were analyzed, and the crevice corrosion of casting samples was analyzed with the CPPT test and the SEM. The results are as follows : 1. Anodic polarization behavior of samples ; Before casting, gold/plastic coping and gold coping was shown to have a similar corrosion pat-terns. Type III casting gold alloy was shown to have a lower corrosion potential and passivation film. Corrosion potential of the case of gold/plastic coping after casting was higher than that of gold coping, but the region of passivation film for gold/plastic coping was smaller than that of gold coping. 2. Galvanic corrosion behavior of samples ; Contact current density between casting gold alloys and gold/plastic before casting was higher than that between gold coping and casting gold alloy Galvanic corrosion of samples after casting was shown to have similar contact current density 3. Crevice corrosion behavior of samples ; Crevice corrosion resistance of casting sample using gold coping was lower than that of cast-ing sample using gold/plastic coping, and a severe corrosion pattern was observed at the abutment-casting gold alloy interface by the SEM.

• Journal of Fashion Business
• /
• v.18 no.2
• /
• pp.132-147
• /
• 2014

The purpose of this study is to classify the appearance concern into groups and analyze the differences of the attitude toward plastic surgery and clothing behavior by groups. Questionnaires are administered to 206 female adults in their 20's-50's living in Deagu and Kyungbook areas from $10^{th}$ July to $19^{th}$ July, 2013. Frequency, factor analysis, reliability analysis, correlation analysis, cluster analysis, ANOVA, Duncan-test and ${\chi}^2$-test were used for data analysis. The appearance concern is categorized as follows: appearance harmony focus and body focus. The attitude toward plastic surgery was found as risk tolerance, image improvement/surgery desire and keeping the secret of surgery. Clothing behaviors are found as individuality focus, other focus, convenience and luxury ostentation. The appearance concern shows a significant correlation with the sub-variable attitude toward plastic surgery and clothing behavior. One test in the groups is determined by demographic variables like occupancy and monthly income. Appearance concerns are classified into three groups as follows: appearance concern group, low appearance concern group and body concern group. The groups show a significant difference in the attitude toward plastic surgery and clothing behavior. This difference indicates that the 20's show a high body focus on their appearance concern, an attitude of image improvement/surgery desire toward plastic surgery and another individuality focus on clothing behavior while 50's care more about convenience in their clothing behavior.

• Korean Journal of Materials Research
• /
• v.20 no.1
• /
• pp.7-11
• /
• 2010

Yttria stabilized zirconia (Y-CSZ) single crystals show plastic deformation at high temperatures by activating dislocations. The effect of strain rate on the plastic behavior of this crystal was studied. As increasing strain rate from $\varepsilon=1.04\times10^{-5} sec^{-1}$ to $2.08\times10^{-5} sec^{-1}$ the yield drop was suppressed and resulted in higher Young's modulus and yield stress. Dislocation structures of the strained crystals were analyzed using a transmission electron microscope to elucidate the plastic behavior of these crystals. In the early stage of plastic deformation, dislocation dipoles and prismatic dislocation loops were formed in both samples. However, dislocation density was increased by increasing strain rate. Strong sessile dislocations were observed in the sample with higher strain rate, which may cause the higher work hardening.