• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.369-372
• /
• 2000

ESO(Evolutionary Structural Optimization) method is known that elements involved low stress value are removed from the previous model or that elements are added around elements involved high stress level on it and then the optimized model is obtained with required weight. Rejection ratio/addition ratio and evolutionary ratio are predefined and elements having lower/higher stress than reference stress, which average Mises stress on edge elements times rejection ratio, are deleted/added. In this study, when the plate having a cutout is subjected various in-plane load, a cutout shape is optimized using ESO method. ANSYS is used to analyse a finite element model and optimization procedure is made by APDL (ANSYS Parametric Design Language). ESO method is useful in rather than a complex structure optimization as well as a cutout shape optimization.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.3
• /
• pp.76-82
• /
• 2000

It is well known that during the oxygen cutting process residual thermal stresses are produced in weldment. The local non-uniform heating and subsequent cooling which takes place during any welding process causes complex thermal strains and stresses to finally lead to residual stresses exceed to the yield stress. High tensile stresses combined with applied structural load in the region near the welded joint can given rise to distortion brittle fracture change of the fatigue strength and stress corrosion cracking. The appropriate treatment of the welded component which reduces the peak of he welding residual stresses is believed to lower risk of the fracture during the service of the structure. In this study the impact loading in oxygen cutting frame was applied to reduce the residual stress. After applying the impact loading redistribution of resid-ual stress was measured by cutting method and the effect of fatigue was tested.

• Journal of Korean Society of Steel Construction
• /
• v.14 no.1
• /
• pp.41-49
• /
• 2002

An efficient algorithm automatically determining cross sectional properties of thin-walled beams is developed using the minimum information about geometry of the cross section. This scheme is applied to automatic calculation of normal and shear stress distribution corresponding to stress resultants as well as sectional constants for complex open and closed thin-walled sections. Numerical examples evaluating section constants and stress distributions is presented and compared with the available reference's results.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.10
• /
• pp.152-163
• /
• 1999

The problem of eigenvalue and eigenvector for v-notched cracks in pseudo-isotropic and anisotropic dissimilar materials was obtained to discuss stress singularities from traction free boundary and perfect bonded interface conditions assuming like the form of complex stress function for v-notched cracks in an isotropic material. Eigenvalues were solved by a commercial numerical program, MATHEMATICA. The relation between wedged angle and material property for eigenvalue, ${\lambda}$ indicating stress singularities of v-notched cracks in pseudo-isotropic and anisotropic dissimilar materials was examined.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.6
• /
• pp.97-103
• /
• 2008

In general, the strength of gears is calculated using the formula of AGMA or JGMA. But these formula can not be applied directly to the strength calculation of the rack and pinion of steering gear assay, because of complex tooth and contact shapes. So Lewis bending stress and Hertzian contact stress formula are generally used for the design of rack and pinion of steering gear assay. But these formula do not also give the exact stress of rack and pinion. In this paper, comparing the finite element analysis results and the experimentally measured values, it is shown that the finite element modeling technique of the rack and pinion of steering assay is reasonable.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2004.05a
• /
• pp.45-46
• /
• 2004

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.7
• /
• pp.977-985
• /
• 2004

An evaluation of fatigue life of welded components is complicated due to various geometrically complex welding details and stress raisers in vicinity of weld beads, ego under cuts, overlaps and blow holes. These factors have a considerable influence on the fatigue strength of welded joints, as well as the welding residual stress which is relaxed depending on the distribution of local stress at the front of the stress raisers. To reasonably evaluate fatigue life, the effect of geometries and welding residual stress should be taken into account. The several methods based on the notch strain approach have been proposed in order to accomplish this. These methods, however, result in differences between analytical and experimental results due to discrepancies in estimated amount of relaxed welding residual stress present. In this paper, an approach that involves the use of a modified notch strain approach considering geometrical effects and a residual stress relaxation model based on experimental results was proposed. The fatigue life for five types of representative welding details, ego cruciform, cover plate, longitudinal stiffener, gusset and side attachment joint, are evaluated using this method.

• Korean Journal of Health Education and Promotion
• /
• v.29 no.3
• /
• pp.63-74
• /
• 2012

Objectives: We aim to investigate association between health behavior, interpersonal/organizational environment and job stress among government officials. Methods: Through health examination and a survey, this cross sectional study investigated 543 government officials working at Central Government Complex in Seoul, Korea. Health behaviors included alcohol drinking, smoking, moderate exercise and food frequency. Interpersonal environment was measured by health behavior practices of significant others and social support for health promotion. And the measures of organizational environment included facilities for exercise, health related norms and health supportive organizational systems. Job stress was assessed by short version of Korean Occupational Stress Scale(KOSS). Results: The level of job stress among female officials was higher than that of male officials. Multivariate logistic model suggested that higher job stress in male officials was significantly associated with lower position(OR=0.267, p<.01) less grain intake(OR=0.642, p<.05), lower level of social support(OR=0.810, p<.01) and abdominal obesity(OR=2.407, p<.05). On the contrary, female officials' stress level was negatively associated with healthy organizational environment(OR=0.725, p<.05). Conclusions: It is suggested that addressing job stress require tailoring intervention by gender characteristics and integration of interpersonal and organizational level approaches.

• Journal of Korean society of Dental Hygiene
• /
• v.22 no.2
• /
• pp.125-132
• /
• 2022

Objectives: The purpose of this study was to examine the relationship between stress and halitosis in a representative sample of Korean adolescents. Methods: This study was based on the 15th Korea Youth Risk Behavior Survey (2019). The final participation rate in the survey was 95.3%; 57,303 out of 60,100 (95.3%) adolescents aged 13-18 years were selected. Multiple logistic regression with complex samples was performed to identify the correlation between stress and halitosis. Stress level was classified as 'very much', 'a little', and 'not much' and halitosis was defined as the presence of an unpleasant odor in the oral cavity. Results: The prevalence of halitosis among students was 21.3%. As a result of multiple regression analysis, the 'a little' [odds ratio (OR); 1.39, 95% confidence interval (CI); 1.29-1.49] and 'very much' stress group (OR; 1.78, 95% CI; 1.66-1.90) exhibited significantly higher risk of halitosis than the 'not much' stress group. Conclusions: A significant correlation between stress and halitosis exists among Korean adolescents. Therefore, psychological factors such as stress should be considered in managing halitosis in adolescents.

• The Journal of Economics, Marketing and Management
• /
• v.12 no.2
• /
• pp.61-71
• /
• 2024

Purpose: This study explores the impact of discrimination experience on stress levels among Seoul's public housing complex residents, emphasizing the moderating role of social capital. Research design, data and methodology: Utilizing the 2019 Seoul public housing (PH) panel data and an ordered logit model, the research categorizes residents based on personal and environmental factors, contrasting them across different local housing price levels. Results: We find that public housing residents' experience of discrimination has a significant impact on stress, and local housing prices are positively related to stress. Interestingly, stress due to discrimination is more pronounced in high-priced neighborhoods, which are associated with real estate inequality. Conversely, this impact is less pronounced in lower-priced neighborhoods. Importantly, social capital not only has a significant moderating effect on stress for all residents, but in high-priced neighborhoods, it also moderates the stress caused by experiences of discrimination for social housing residents. Conclusions: These findings highlight the need for policy interventions to strengthen social capital and address socioeconomic disparities in public housing, and are significant for analyzing the nuanced relationship between neighborhood, housing affordability, discrimination, and stress in urban communities for public housing residents, which is a socially problematic issue.