• Title/Summary/Keyword: Stress Field

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Preceding Research for Developing Floral Design Education Contents (화예디자인 교육 콘텐츠 개발을 위한 선행연구)

  • Hong, Yun Joo
    • Journal of the Korean Society of Floral Art and Design
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    • no.42
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    • pp.97-116
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    • 2020
  • In this paper, the need for lifelong education and distance education is increasing due to the decrease of population and the increase of life expectancy. In addition, the popularization and everydayization of education, which combines daily life and learning, is an educational feature. Individuals can more easily access knowledge, and video plays an important role. Video content is the most basic medium that leads to the popularization and daily life of education. With the development of information and communication technology, popularization of media content production and editing technology, anyone can easily create and share. The video education contents business is expected to increase globally through SNS. Especially, the video contents education industry related to flower design is regarded as a suitable content field in an era where environment is essential. In the modern era, characterized by the "one-person household, one-person media" era, the environment of plants protects people from stress by restoring human emotional efficiency, environmental comfort, and stability. In other words, because humans have a preference for nature, plants play an important role for humanity recovery. Against this backdrop, flower design is expected to be a promising industrial sector with high growth, high value added and high job creation effects. In the era of the fourth revolution of the human race, competitive video contents are expected to influence the growth of the future country. will be.

Flow Safety Assessment by CFD Analysis in One-Touch Insertion Type Pipe Joint for Refrigerant (CFD 해석을 이용한 냉매용 원터치 삽입식 파이프 조인트의 유동 안전성 평가)

  • Kim, Eun-young;Park, Dong-sam
    • Journal of the Society of Disaster Information
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    • v.18 no.3
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    • pp.550-559
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    • 2022
  • Purpose: Pipes are widely used as applied devices in many industrial fields such as machinery, electronics, electricity, and plants, and are also widely used in safety-related fields such as firefighting and chemistry. With the diversification of products, the importance of technology in the piping field is also increasing. In particular, when changing the existing copper pipe to stainless steel, it is necessary to evaluate safety and flow characteristics through structural analysis or flow analysis. Method: This study investigated the safety by flow analysis of the 6.35 inch socket model, which are integrated insert type connectors developed by a company, using CFD analysis technique. For CDF analysis, RAN model and LES model are used. Result: As results of the analysis, amplitude of the pressure fluctuation acting on the wall of the piping system is formed at a level of 3,780 Pa or less, which is a very small level of pressure compared with the operating pressure or design stress of the refrigerant piping. Conclusion: These results mean that the effect of vibration caused by turbulence on the structural safety of the pipe is negligible.

Physiological and Psychological Responses to Landscape Experiences in a Natural Forest and a VR Forest (자연숲과 VR숲의 경관 체험에 따른 생리 및 심리적 반응)

  • Kim, Il-Doo;Shin, Won-Soep
    • Korean Journal of Environment and Ecology
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    • v.36 no.5
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    • pp.525-534
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    • 2022
  • In this study, we investigated the psychological and physiological effects of experiences in real natural forests and virtual forests using artificially controllable VR. The experiment tested 60 adult college students in a natural forest and a graduate seminar room where external light was blocked. It evaluated the effects of the natural and the VR forest environments by comparing the psychological and physiological recovery of the subjects. Psychometric testing using the PANAS psychological index showed increased positive emotions and decreased negative emotions after experiencing forest scenery in the natural and VR forest environments. And a stress index, based on measuring cortisol in saliva, decreased significantly in the subjects in both environments. The experiment results can be used to support the creation of a psychological and physiological recovery environment with VR for those who cannot go to the natural forest due to certain restrictions such as physical distance, mobility difficulties, etc. It is expected that the results will be the basis for further research into the visual effects of forest healing and also for widening the use of VR, a technology of the fourth industry, in the field of forestry.

An Experimental Study on the Settlement Characteristics of Soft Ground in the Central West Coast Region (서해안 중부지역 연약지반의 침하특성 분석을 위한 실험적 연구)

  • Kim, Joon-Seok
    • Journal of the Society of Disaster Information
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    • v.17 no.4
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    • pp.786-793
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    • 2021
  • Purpose: An experiment was conducted to analyze the characteristics of the settlement of soft clay soil in the central region of the west coast of Korea, which has a high silt content and is difficult to predict settlement due to various stress histories. Method: Field experiments were conducted for three cases. The settlement amount of the subsidence plate was measured in each case, and the following conclusions were drawn by analyzing Terzaghi's one-dimensional consolidation settlement amount, both the hyperbolic method and the Asaoka method. Result: The predicted value by Terzaghi was analyzed to be the largest in all cases, and it was predicted to be 111% to 187% larger than the subsidence plate settlement value. That is, the subsidence plate settlement value, which is the amount of settlement of the actual ground, showed a settlement of 53.4~89.9% compared to the predicted value of Terzaghi. Therefore, it was analyzed that the expected settlement of the Terzaghi method in the clay soft ground of the central west coast of Korea is more than the actual settlement. Conclusion: It was analyzed that the Asaoka method and the hyperbolic method presented relatively similar results, and in practice, predicting the settlement amount smaller than the actual settlement amount may cause a risk, so the hyperbola analysis method predicted 6~14% larger than the actual settlement amount can be used as a safety side.

Evaluation of Mechanical Characteristics and Concentration Target Layer Applicability of Silty Sand by Fines Content (실트질 모래의 세립분 함유율에 따른 역학적 특성 및 압밀 대상층 적용성 평가)

  • Jung-Meyon Kim;Min-Seo Kang;Jong-Joo Kim;Seung-Joo Lee;Young-Seok Kim;Chan-Young, Park;Yong-Seong, Kim
    • Journal of the Korean Geosynthetics Society
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    • v.22 no.3
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    • pp.37-46
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    • 2023
  • In this paper, the physical properties, stress deformation and strength characteristics, density and permeability characteristics of silty sand (SM) by fines content were analyzed through indoor tests. also based on the results of the indoor tests, a compact analysis was performed according to the content of SM, and the applicability of SM ground to the compacted target layer was evaluated by comparing it with the measurement data of the actual problem site. As a result of indoor tests and compression analysis, SM changed its mechanical properties from sandy soil to viscous soil when the fine particle content was 35% or higher, and using field measurement data, SM was found to have a higher compression tendency than direct subsidence. Therefore, the mechanical characteristics of SM above Fc 35% are considered to be similar to that of viscous soil, which is different from the compression characteristics of the tendency of immediate subsidence to conventional sandy soil, so it is necessary to present the mechanical characteristics of SM through further research. The research findings highlight the importance of considering consolidation settlement in silty sand (SM) when evaluating soft soil conditions. These findings can aid in revising criteria for assessing weak ground conditions by providing essential engineering property data based on varying fines content in silty sand.

Analysis of the Causes of Clustered Scismicity Registered in Yeoncheon, the Middle Part of the Korean Peninsula through Gravity Field Interpretation and Modeling (중력이상 수치해석을 통한 연천지역 군발지진 원인분석)

  • Sungchan Choi;Sung-Wook Kim;Eun-Kyeong Choi;Younghong Shin;Tae-Kyung Hong
    • Economic and Environmental Geology
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    • v.55 no.6
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    • pp.633-648
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    • 2022
  • Gravity data were analyzed to identify the cause of clustered seismicity that occurred intensively in Yeoncheon, located in the central part of the Korean Peninsula. Our analysis suggests that the En echelon faults developed in the northwest-southeast direction. In addition, in the eastern part of the Dongducheon Fault, it was interpreted that high-density lower bedrock intermittently lifts close to the surface due to vertical tectonic movement accompanied by a flower structure. The fracture zone of the Dongducheon Fault is estimated that the width is about 200 m, the depth is at least 5 km, and the density is about 15% lower than the adjacent rocks. It is analyzed that the shallow earthquakes that occurred within 5 km depth was concentrated along the low-density En echelon fault fracture zone developed between the high-density rocks intruding close to the surface. Therefore, the earthquakes can be interpreted as the result that the north-south stress caused by the dextral tectonic movement of the Dongducheon Fault activated the En echelon fault in the northwest-southeast direction.

Calculation of Bearing Capacity of Tapered Drilled Shafts in Cohesionless Soils Using Shape Factor (형상계수를 이용한 사질토 지반에 타설된 테이퍼말뚝의 지지력 산정)

  • Paik, Kyu-Ho;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.24 no.12
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    • pp.13-22
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    • 2008
  • Fourteen calibration ehamber tests were performed using one cylindrical and two tapered piles with different taper angles to investigate the changes of the bearing capacity of tapered piles with soil state and taper angle of piles. The results of calibration chamber tests show that the ultimate base resistance of tapered piles increases with increasing mean stress and relative density of soil. It also increases with increasing taper angle for medium sand, but with decreasing taper angle for dense sand. The ultimate shaft resistance of tapered piles increases as vertical and horizontal stresses, relative density and taper angle increase. Based on the results of model pile load tests, a new design method with shape factors for estimation of the bearing capacity of tapered piles is proposed considering the effect of soil state and taper angle on bearing capacity of tapered piles. In order to check the accuracy of predictions calculated using the new method, middle-scale field pile load tests were also conducted on cylindrical and tapered drilled shafts in clayey sand. Comparison of calculated values with measured ones shows that the new design method produces satisfactory predictions tor tapered piles.

A Survey on Korean Medicine Doctors' Recognition and Treatment for Developing Korean Medicine Clinical Practice Guideline of Female Infertility (여성 난임 한의표준임상진료지침 개작을 위한 한의사의 인식과 치료에 관한 실태조사)

  • Hyo-Jeong Jung;Dong-Il Kim;Su-Ji Choi;Su-In Hwang;Young-Jin Yoon;Jang-Kyung Park
    • The Journal of Korean Medicine
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    • v.43 no.3
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    • pp.122-138
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    • 2022
  • Objectives: This study was conducted to develop a Korean Medicine(KM) Clinical Practice Guidelines(CPG) of female infertility. We conducted this questionnaire survey to reflect the experiences of Korean Medicine doctors(KMD) and clinical field in Korea. Method: We sent a questionnaire survey to KMD belonging to the Association of Korean Medicine by e-mail. We received 665 responds, and analyzed the answers. Results: 51.2% of respondents knew the previously developed CPG of female infertility, and 18.3% actually used. 83.3% agreed about the necessity of CPG of female infertility, and 80.3% had practical use plan. 90.2% of respondents treated less than 5 infertility woman for a month. 22.7% of respondents treated 50% of patients with collaborative treatment of KM and Western medical treatments. The main age group of patients was '35~40 years'(54.7%), and the most common cause was unexplained infertility(61.7%). The most common pattern identification of female infertility patients was Kidney deficiency(55.4%). KMD used 'a combination of decoction of herbal medicine, acupuncture and moxibustion treatment' the most(43%), and 'a decoction of herbal medicine treatment alone' was next(35%). 84.2% conducted lifestyle modification education about diet, stress, exercise etc. Conclusion: We figured out Korean Medicine doctors' recognition about CPG of female infertility, preference of treatments, and also characteristics of patients visiting Korean Medical clinics to make a practical CPG reflecting clinical situation.

A Study on Reinforcement Method of Concrete Block for Direct Fixation Tracks on Serviced Light Rail Transit (공용중인 경전철 직결 궤도 콘크리트 도상블록의 보강 방안 연구)

  • Jung-Youl Choi;You-Song Kang;Dae-Hee Ahn;Jae-Min Han;Jee-Seung Chung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.633-640
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    • 2023
  • In this study, numerical analysis was performed based on field investigation to derive an appropriate reinforcement method by analyzing the displacement behavior characteristics of concrete blocks generated in the direct fixation track on the bridges of the serviced light rail transit. The track of this study was a direct fixation track on a sharp curved track, and the problem of movement of the concrete blocks installed on the bridge deck in the longitudinal and lateral directions occurred. In this study, based on the finite element model using 3D solid elements, the behavior of the direct fixation track that could be occurred under operating load conditions was analyzed. In addition, the reinforcement effect of various reinforcement methods was analyzed. As a result of analyzing the lateral displacement before and after reinforcement, it was analyzed that the maximum lateral displacement after reinforcement under the extreme lateral wheel loads significantly decreased to about 3% (about 0.1mm) compared to before reinforcement. In addition, as a result of examining the generated stress of the filling mortar, bridge decks, and reinforcing bar, it was analyzed that all of them secured a sufficient safety factor of 2.6 or higher, and the optimal conditions for the reinforcement method were derived. Therefore, it is judged that the number of anchoring reinforcements and symmetrical anchor placement reviewed in this study will be effective in controlling the occurrence of lateral displacement of concrete blocks and securing the structural integrity of bridges and concrete blocks.

A Meshless Method Using the Local Partition of Unity for Modeling of Cohesive Cracks (점성균열 모델을 위한 국부단위분할이 적용된 무요소법)

  • Zi, Goangseup;Jung, Jin-kyu;Kim, Byeong Min
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5A
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    • pp.861-872
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    • 2006
  • The element free Galerkin method is extended by the local partition of unity method to model the cohesive cracks in two dimensional continuum. The shape function of a particle whose domain of influence is completely cut by a crack is enriched by the step enrichment function. If the domain of influence contains a crack tip inside, it is enriched by a branch enrichment function which does not have the LEFM stress singularity. The discrete equations are obtained directly from the standard Galerkin method since the enrichment is only for the displacement field, which satisfies the local partition of unity. Because only particles whose domains of influence are influenced by a crack are enriched, the system matrix is still sparse so that the increase of the computational cost is minimized. The condition for crack growth in dynamic problems is obtained from the material instability; when the acoustic tensor loses the positive definiteness, a cohesive crack is inserted to the point so as to change the continuum to a discontiuum. The crack speed is naturally obtained from the criterion. It is found that this method is more accurate and converges faster than the classical meshless methods which are based on the visibility concept. In this paper, several well-known static and dynamic problems were solved to verify the method.