• 한국기계가공학회지
• /
• 제11권6호
• /
• pp.115-122
• /
• 2012

The purpose of this study is to optimize the design of the jack-up platform for 5MW offshore wind turbine system. Considering all the environmental loads such as currents, waves, winds and so on, the members of structures have been designed and optimized based on the AISC and API-RP-2A to be within the allowable stress even in the most critical and severe condition. In addition to the above strength check of structural members, the joint punching shear check and the hydrostatic collapse check are also performed where they are required for the design. The design life of the jack-up platform is 50 years for the static strength check and the fatigue design life is 100 years including to the DFF(Design Fatigue Factor) of 2.0 to have enough stability and workability for the design optimization.

• Journal of the Korean Wood Science and Technology
• /
• 제27권4호
• /
• pp.51-56
• /
• 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.

• Nuclear Engineering and Technology
• /
• 제30권5호
• /
• pp.470-484
• /
• 1998

An analysis program for the evaluation of pressure vessel integrity under pressurized thermal shock (PTS) is developed. For given material properties and transient history such as temperature and pressure, the stress distribution is calculated and then stress intensity factors are obtained for a wide range of crack sizes. The stress intensity factors are compared with the fracture toughness to check if cracking is expected to occur during the transient. Using this program a round robin problem of PTS during a small break loss of coolant transient has been analyzed as a part of the international comparative assessment study. The allowable maximum reference nil-ductility transition temperatures are determined for various crack sizes.

• 한국해양공학회지
• /
• 제17권5호
• /
• pp.48-56
• /
• 2003

This paper has developed an efficient nonlinear finite element method that covers both initial deformations and initial stresses of general distribution in calculating the ultimate strength of ring-stiffened cylinders. The developed method and two widely-used commercial codes (NASTRAN and ABAQUS) were simultaneously applied to the same analysis model within the extent of those commercial codes' coverage to check the validity of the present method. After the validity check, it was used for parametric studies for more general cases of initial stress distribution, which produced some useful information about the imperfection sensitivity of the ultimate strength of ring-stiffened cylinders.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
• /
• 제6권1호
• /
• pp.51-59
• /
• 2003

This paper has developed an efficient nonlinear finite element method that covers both initial deformations and initial stresses of general distribution in calculating the ultimate strength of ring-stiffened cylinders. The developed method and two widely-used commercial codes (NASTRAN and ABAQUS) were simultaneously applied to the same analysis model within the extent of those commercial codes' coverage to check the validity of the present method. After the validity check, it was used for parametric studies for more general cases of initial stress distribution, which produced some useful information about the imperfection sensitivity of the ultimate strength of ring-stiffened cylinders.

• 대한기계학회논문집A
• /
• 제33권4호
• /
• pp.401-408
• /
• 2009

This study is performed to check the three dimensional characteristics of residual stress in the dissimilar metal weld. Although two dimensional analysis has been widely used for the assessment of weld residual stress, it has limitations to understand the stress distribution of the third direction. 3-D analysis was done to understand residual stress distribution of the welded plate. A simple butt-welded plate was considered to show the stress variation on all direction. A mock-up plate weldment was fabricated with SA-508 and F316L, which are widely used in nuclear power plants. The analysis results were validated with the measured values in the mock-up.

• 동국한의학연구소논문집
• /
• 제5권
• /
• pp.33-52
• /
• 1996

The purpose of this study was to investigate efficient treatment in obesity. In order to help clinical application in obesity treatment, this study was performed to investigate the cause and treatment in obesity. The main finding of this study were as follows. 1. In the cause of oriental medicine in obesity, that were moisture(濕), phlegm(痰), gore(瘀), the productive heat(積熱), overeating, supemutrition, underaction, heredity and habitude, psychologic factor(stress) etc. 2. In the western medicine, the cause of obesity were genetic cause, endocrine disorder, hypothalamic extraodinary and secondary effect of drug. But simple obesity is the greater part. Also there were psychologicai and environmental causes. 3. Ear acupuncture of wide application were Naebunbi, Sinmun, Taejang, $ij{\check{o}}m$, $Pyej{\check{o}}m$, $Bij{\check{o}}m$ etc. 4. Body acupuncture of application were $Naej{\check{o}}ng$, $Sangg{\check{o}}h{\check{o}}$, Pungnyung, Kokchi, $Sam{\check{o}}mgyo$, $Umn{\check{o}}ngch{\check{o}}n$ etc. 5. In oriental medical treatment of obesity, Bangpungtongs ngsan(防風通聖散), Daesihotang(大柴胡湯), Seungkitang(承氣湯), Bangkihwangkitang(防己黃?湯), Richulsaryeungtang(二朮四笭湯), Taeksatang(澤瀉湯), Opieum(五皮飮), Gongyundan(控涎丹) etc were wide applicated. 6. The western medical treatment in obesity encourage the dietary cure, exercise cure and behavior adjustment than medical therapy or operation. In treatment of obesity, the dietary cure and herb-drug therapy, ear acupuncture and body acupuncture are effective. But weight maintenance after treating is more important. After all the continuous dietary cure, behavior adjusting cure and exercise cure are necessary.

• Journal of Welding and Joining
• /
• 제27권4호
• /
• pp.32-37
• /
• 2009

Alloy 600 and Alloy 82/182 materials have been used widely in PWR plants. But these materials are known to be susceptible to PWSCC(Primary Water Stress Corrosion Cracking). Recently, there have been several PWSCC events in major components due to repair welding, because repair welding in the dissimilar metal welds during the construction increases residual stress significantly on the inner surface of welds. In this paper, various residual stress analyses for repair welding were performed using FEM to check the effect of repair welding on residual stress distributions in PZR safety/relief nozzle. The results indicate that for inside surface repair welding, high tensile residual stress is developed on the inside surface of the nozzles.

• 대한조선학회지
• /
• 제52권2호
• /
• pp.19-24
• /
• 2015

A reliable assessment and analysis of the condition of high pressure and temperature steam pipelines requires defining stress state, which will take into consideration not just the impact of internal pressure and temperature but all applied loads. For that, usage of modeling and numerical methods for calculation and analysis of stress state is essential. The main aim of piping stress analysis is to check the design of piping layout, which will allow simple, efficient and economical piping supports and provide flexibility to the piping system for loads and stresses. The piping stress analysis is carried out using CAESER II software. By using this software we can evaluate stresses, stress ratios, flange condition, support loads, element forces and displacements at each node and points. In this paper, only the maximum and minimum displacement results are tabulated, which is also shown in detail by an example of main steam pipelines of UST Main Engine System [1].

• 동의신경정신과학회지
• /
• 제28권3호
• /
• pp.183-194
• /
• 2017

Objectives: Chijasitang (CJST) has been prescribed for patients with anxiety disorder, and is believed to treat insomnia. The present study was carried out to investigate whether Fructus Gardeniae, Fermented Semen Sojae Preparatum and CJST have beneficial effects on treating anti-stress. Methods: The mice were divided into the following groups: normal, control, positive control, and experimental. Then, the experimental groups were further divided into the Fructus Gardeniae group (FG), the Fermented Semen Sojae Preparatum group (FS), the Chijasitang water extract group (CJSTW), and the Chijasitang 30% ethanol extract group (CJSTE). In the positive control group, a single dose of imipramine ($500{\mu}g/g$) was applied to the mice. In the experimental groups, each single dose of FG, FS, CJSTW and CJSTE ($50{\mu}g/g$) was applied to the mice. After one hour, the mice in all groups except the normal group were exposed to immobilization stress. Their body weights, phagocytosis, nitric oxide in macrophage, corticosterone, and adrenocorticotropic hormone (ACTH) were observed. Results: Fructus Gardeniae, Fermented Semen Sojae Preparatum and Chijasitang prevented weight loss and suppressed the decrease of phagocytosis in the mice after their exposure to immobilization-stress. Although they did not influence the amount of NO, they suppressed the increment of ACTH and corticosterone in the immobilization-stressed mice. Conclusions: According to the results of this study, they suggest that Fructus Gardeniae, Fermented Semen Sojae Preparatum and Chi-Ja-Si-Tang all have some anti-stress effects.