• Title/Summary/Keyword: External Moment

Search Result 264, Processing Time 0.021 seconds

Inelastic Nonlinear Analysis of Arch Truss and Space Truss Structures (아치 트러스 및 공간 트러스 구조의 비탄성 비선형 거동해석)

  • Kim, Kwang-Joong;Jung, Mi-Roo;Kim, Yeon-Tae;Baek, Ki-Youl;Lee, Jae-Hong
    • Journal of Korean Association for Spatial Structures
    • /
    • v.8 no.5
    • /
    • pp.47-58
    • /
    • 2008
  • Spatial structure is an appropriate shape that resists external force only with in-plane force by reducing the influence of bending moment, and it maximizes the effectiveness of structural system. With this character of the spatial structure, generally long span is used. As a result, large deflection is accompanied from the general frame. the structure is apt to result in a large deflection even though this structure experiences a small displacement in absence. Usually, nonlinear analysis in numerical analysis means geometric nonlinearity and material nonlinearity and complex nonlinearity analysis considers both of them. In this study, nonlinear equation of equilibrium considering geometric nonlinearity as per finite element method was applied and also considered the material nonlinearity using the relation of stress-strain in element. It is applied to find unstable result for tracing load-deflection curve in the numerical analysis tech. especially Arc-length method, and result of the analysis was studied by ABAQUS a general purpose of the finite element program. It is found that the present analysis predicts accurate nonlinear behavior of plane and space truss.

  • PDF

Dynamic Modeling and Simulation of a Towing Rope using Multiple Finite Element Method (다물체 요소이론을 이용한 예인줄 동역학의 모델링 및 시뮬레이션)

  • Yoon, Hyeon-Kyu;Lee, Hong-Seok;Park, Jong-Kyu;Kim, Yeon-Gyu
    • Journal of Navigation and Port Research
    • /
    • v.36 no.5
    • /
    • pp.339-347
    • /
    • 2012
  • After towing rope connecting a barge to a tug was subdivided into multiple finite elements, then those dynamic models was established using Newton's second law and considering the external force and moment such as tension, drag, Coriolis force, gravity, buoyancy, and impact due to free surface acting on each element. While the previous research on the model of towing rope considered only translation, five-degree-of-freedom equations of motion except roll based on the body-fixed frame were established in this paper. All elements are connected by a spring and a damper, and the stiffness of the spring was set as the equivalent value of the real rope. In order to confirm the established multiple finite element model, various scenarios such as freely falling of towing rope in the air and above the free surface, accelerating of a tug which tows a barge connected by towing rope, and sinusoidal moving of a tug were set up and simulated. As the results, the trajectories of the tug, the barge, and the towing rope showed good tendencies to the ones of real expected situations.

Performance Evaluation of Long Span Bridge Columns Strengthened with High-Performance Glass Fiber (고성능 유리섬유로 보강된 해상장대교량 교각의 보강성능평가)

  • Chang, Chun-Ho;Jang, Kwang-Seok;Lee, Jae-Uk
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.16 no.1
    • /
    • pp.125-133
    • /
    • 2010
  • Researches and studies which have been conducted so far on external confinement of long span concrete columns have mainly concentrated on concentric loading. But, long span bridge concrete columns over the sea are mainly subjected to concentrated axial load, and at the same time lange amount of moment by eccentric load. This paper experimentally investigates the performance of externally confined high-strength concrete columns subjected to loading mechanism and evaluates the effectiveness of two confinement materials carbon fibre and high performance glass fibre. Twelve short columns with the same dimensions were cast and tested Six columns were reinforced with hoop bars, the remaining six columns were reinforced with spiral bars and wrapped with three layers of carbon failure and high performance glass FRP sheets. Test variables considered were the shape of internal reinforcement and strengthening materials according to loading location. The experimental results showed that eccentric load could obviously lower down the maximum failure load of FRP-confined concrete columns, compared with the columns under concentric load. And compared with the carbon FRP-confined reinforced concrete columns, high performance glass FRP-confined columns displayed a higher load capacity and ductility, when tested both concentrically and eccentrically.

A study on the self-esteem of the gifted children (영재아의 자아존중감에 관한 연구)

  • Song, Su-Jie
    • Journal of Gifted/Talented Education
    • /
    • v.10 no.2
    • /
    • pp.87-108
    • /
    • 2000
  • This study analyzes the factors influencing self-esteem of the gifted children. The factors are divided into the environmental ones and innate ones. The purposes of this study is presented as follows. 1) To analyze the environmental factors influencing self-esteem of the gifted children (1) whether the education period affects self-esteem of the gifted children? (2) what influences do the manners of parental child-rearing behavior make? (3) what influences do peer relationships make on self-esteem of the gifted children? 2) To analyze the innate factors influencing self-esteem of the gifted children (1) does the gender make a difference to self-esteem of the gifted children? (2) does the level of intelligence make a difference to self-esteem of the gifted children? (3) what influences does the locus of control make on the self-esteem of the gifted children? To solve these questions 120 gifted children were selected, who were taking a special education program at C Korea Academy of Gifted Education located at Yangjae-dong Seocho-gu. They were 1st to 3rd grades at elementary school. We used Hare Self-Esteem Scale developed by Bruce R. Hare in 1985, the Index of Peer Relations developed by Hudson in 1986, and Nowicki & Strickland Locus of Control Scale developed by Nowicki and Strickland in 1973. At the other hand the nursing behaviors of 120 mothers of the gifted, were also investigated, based on the Korean Maternal Behavior Inventory, developed by Sungyeon Park in 1989 with some modifications. For statistical analysis we adopted SPSS, a computer software, and calaulated the coefficient of internal appropriateness and the frequencies and percentages of general aspects of the cases. We analysed the factors influencing the self-esteem of the gifted children by way of Pearson's product moment correlation coefficient, t-test, ANOVA, and multiple regression analysis and Duncan for ex-post-facto approval. The results of this study can be summarized as follows. 1) Influences of the environmental factors on the self-esteem of the gifted children: (1) The duration of education period had a significant effect on the self-esteem; the longer the duration were, the higher self-esteem they possessed. (2) Of parental child-rearing behaviors, active involvement had positive influence on the self-esteem; on the contrary, authoritarian control and overprotection had negative influences on the self-esteem. (3) An acceptable peer relationship had a positive influence on the self-esteem of the gifted children. 2) Influences of individual innate characteristics on the self-esteem of the gifted children: (1) The gender made no difference on the self-esteem of the gifted. (2) The intelligence did not have a statistically significant effect on the self-esteem of the gifted. (3) When the locus of control was external, the self-esteem of the gifted tended to be low.

  • PDF

A case study for prediction of the natural ventilation force in a local long vehicle tunnel (장대도로터널의 자연환기력 예측 사례연구)

  • Lee, Chang-Woo;Kim, Sang-Hyun;Gil, Se-Won;Cho, Woo-Chul
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.11 no.4
    • /
    • pp.395-401
    • /
    • 2009
  • One of the key design factors for the ventilation and safety system at extra long tunnel is the airflow velocity induced by the natural ventilation force. Despite of the importance, it has not been widely studied due to the complicated influencing variables and the relationship among them is difficult to quantify. At this moment none of the countries in the world defines its specific value on verified ground. It is also the case in Korea. The recent worldwide disasters by tunnel fires and demands for better air quality inside tunnel by users require the optimization of the tunnel ventilation system. This indicates why the natural ventilation force is necessary to be thoroughly studied. This paper aims at predicting the natural ventilation force at a 11 km-long tunnel which is in the stage of detailed design and will be the longest vehicle tunnel in Korea. The concept of barometric barrier which can provide the maximum possible natural ventilation force generated by the topographic effect on the external wind is applied to estimate the effect of wind pressure and the chimney effect caused by the in and outside temperature difference is also analyzed.

Sluice Gates Control Monitoring of Oil Pressure-Machine Using FDC Tuning Control Technique (FDC 동조제어기법을 이용한 유압-기계식 수문 제어 모니터링)

  • Heo, Gwanghee;Kim, Chunggil
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.30 no.4A
    • /
    • pp.337-342
    • /
    • 2010
  • Generally most sluice gates are closed and opened by a mechanical winch, a winch using an oil-pressure, or a winch mixing both. Because of their size and structure, they should be safely operated with more than two pulling devices helping each other. At the moment of their opening and closing, there usually occur some additional loads to the structure which cannot be exactly measurable at the stage of designing. Such additional loads can cause the sluice gate to be unbalanced and make it hard to open and close the gate, and by also overloading a winch, they can inflict a significant damage to the safety of the sluice gate. This paper explains a FDC(Force-Displacement Control) system which simultaneously considered the oil-pressure and displacement in order to evenly distribute the force and make a winch balanced at the opening and closing motion. This FDC system was implemented by means of the PID(Proportional Integral Derivative) function of XG 5000 program. It was experimented on a model of the sluice gate winch with the hydraulic oil pressure cylinder. The experiments showed that the developed FDC system made the winch of hydraulic oil pressure cylinder open and close cooperatively in spite of various external loads. Therefore the FDC system is proven effective when it is applied to a winch of sluice gate.

A Study on the Required Horsepower of Tugboats at Jeju Port for Car Ferries - Focusing on Car Ferry H - (카페리여객선 제주항 입출항 시 예선 사용 기준에 관한 연구 - 카페리여객선 H호를 중심으로 -)

  • Byung-Sun Kang;Chang-Hyun Jung
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.30 no.2
    • /
    • pp.209-216
    • /
    • 2024
  • Four accidents occurred between 2020 and 2022 after car ferries built according to a coastal passenger ship modernization plan collided with other ships or came into contact with the dock when entering Jeju Port. Accidents primarily occurred owing to careless ship handling and drift by wind during ship handled by herself using bow and stern thrusters without tugboats. Accordingly, in this study, we analyzed the collision accident focusing on car ferry H and the critical wind speed at which the ship cannot be controlled using its own power, tugboat operation plan in increasing wind speed were proposed based on the power required for the ship to berth parallel to the pier without a tugboat considering the external force and moment generated while the ship is berthing. A analysis of the critical wind speed of car ferry H by relative wind direction when using tugboats or not according to the loading status and the berthing speed, showed that one tugboat should be used at the stern when the lateral wind speed is over 10 m/s and two tugboats should be used when the lateral wind speed is over 14m/s berthing at Jeju port.

An Investigation on the human nature in philosophy of Wang Yang-Ming and Buddhism from a Kantian point of view (칸트의 관점에서 본 왕양명과 불교의 인간관)

  • Park, Jong-sik
    • Journal of Korean Philosophical Society
    • /
    • v.131
    • /
    • pp.165-197
    • /
    • 2014
  • In this paper, I investigate on the human nature in philosophy of Wang Yang-Ming and Buddhism from a Kantian point of view. The core argument of the philosophy of Wang Yang-Ming, Buddhism and Kant is that all human beings have the pure abilities a priori to overcome themselves, to realize their own potentialities. This is called immanent transcendence. At this time human beings can be free. Kant, Wang Yang-Ming and Buddhism claim that all human beings themselves will overcome their desires from their mind and body through the immanent transcendence, reflection and contemplation on their own. When we give up the external knowledges, throw away obsessions with the selfish desires and go back to our inside, we can see our original nature. To have an insight into this inner nature, to respect the moral law a priori, this is to overcome the ourselves, and to be a Grate Man(聖人) and a Buddha. This way is the only way to be a Grate Man and a Buddha. The main proposition of Wang Yang-Ming's philosophy is expressed 'There are no things without mind.'(心外無物) The core of Kant's transcendental philosophy is called the Copernican Revolution by himself. Copernican Revolution means the transition from the object-centered epistemology to the subject-centered epistemology. 'Innate Knowing'(良知) and 'Perform Innate Knowing'(致良知), 'All human beings have the mind of Buddha'(一切衆生悉有佛性) contain the apriority, immanence of Moral Law. In this respect, the theory of Innate Knowing in Wang Yang-Ming and mind of Buddha in Buddhism, pure Moral Law in Kant has the same structure grounded in subjectivity. Even if we have the mind of Buddha, innate Knowing, moral law a priori, the reason why we don't know our original nature is that we fall into the obsessions with selfish desires, and that we have inclination to external interests. So the moment you see our original nature, ordinary people themselves turn into a Buddha. These changes and transitions are immanent transcendence. All human beings have the ability to do this changes and transitions. Buddha does not exist outside of us, but it exists with our reflections on our human nature. Buddha can not existed without our insight into the our innate Ego. Where there is our original nature, there is a Buddha. So Buddha is called the another name of the original figure of human beings.

A Comparative Study on Injury Severity, Self esteem, Health Locus of control and Health Promotion Lifestyles between Helmeted and Nonhelmeted Motorcycle Accident Victims (오토바이 사고환자의 안전모 착용여부에 따른 뇌 손상비교와 자아존중감, 건강통제위 성격, 건강증진행위의 비교연구)

  • 최스미
    • Journal of Korean Academy of Nursing
    • /
    • v.23 no.4
    • /
    • pp.585-601
    • /
    • 1993
  • Data on 63 patients who had had motorcycle accidents and who were admitted to four general hospitals in the Chung Chung Nam Do area from July / 1993 to August 1993 were analyzed. The tool used for this study was a structured questionnaire which consisted of ten items on self- esteem, 18 items on health locus of control and 37 items profiling health prometion lifestyle. Injury severity scores were calculated bated based on data from the patients’ medical records. The collected data were analyzed using the SPSS, yielding descriptive statistics, t-test, ANOVA, Pearson’s Product Moment Correlation. The findings of this study are as follows. 1) Of the 63 injured motorcyclists, 35(55.6%) were helmeted and 28(44.4%) were nonhelmeted, and the nonhelmeted motorcyclists were predominantly young and male. The demographic variables for the helmeted and nonhelmeted groups were heterogeneous for age and occupation. 2) The results of the comparison between the two groups showed a statistically significant difference in the injury severity score(t=-4.70, p=0.000). The helmeted group had lower scores on injury severity score (9.00±3.93) than the nonhelmeted group(14.32土5.05). More than 60% of the nonhelmeted motorcyclists had brain injuries compared to only a third of the helmeted cyclists. 3) There .was a statistically significant difference between the two groups on self esteem(t=4.5, 000). The helmeted group had a higher mean score (31.27±2.72) than the nonhelmeted group(27.46±3.80). 4) The means for Internal health locus of control (IHLC), Powerful others health locus of control (PHLC), and Chance health locus of control (CHLC) in the two groups were similar to instrument norms reported in other literature. The mean scores on the IHLC in the two groups were higher than scores on the PHLC or the CHLC. However, there was a significant difference between the mean scores for the two groups on the PHLC (t=2.85, P=0.006). 5) The mean score for the helmeted group on the health promotion lifestyle profile was higher than the mean score for the nonhelmeted group(107.30±11.10, 96.57土 15.54 respectively), and there was a significant difference between the mean scores (t=3.64, p=0.001) . The highest score for helmeted group on the health promotion lifestyle profile was in the health care domain. However, for the nonhelmeted group the highest score was in the exercise domain and the lowest score was in the health care domain. 6) With regard to the relationship between health promotion lifestyle, health locus of control and self esteem in the two groups, the correlation coefficient between health promotion lifestyle and internal health locus of control for the helmeted group was 50(p〈0.01). For the nonhelmeted group, there was no correlation between health promotion lifestyle and internal health locus of control. However, there were significant correlation between health pro-motion lifestyle and external locus of control(r=0. 46, p〈0.01), and self esteem(r=0.495, p〈0.01). 7) Among the demographic variables, age and education had an impact on individual’s self-esteem The modifying factors of age made a contribution to explaining health - promoting lifestyle. In the present study, more than 40% rf the motorcyclists were riding without a helmet. The incidence of brain injury for patients riding without a helmet was nearly twice as high in the nonhelmeted rider as compared to the helmeted rider. The nonhelmeted motorcyclists in this study had lower self-esteem, obtained a higher score on the IHLC, and were not strongly engaged in performing health promotion activities as compared to the helmeted riders. However, some of the nonhelmeted riders who had a strong belief in PHLC were positively associated with engaging in health promotion activities. Based on the results obtained from this study, strategies to promote helmet usage for motorcyclists have to be developed.

  • PDF

Analysis of Image Distortion on Magnetic Resonance Diffusion Weighted Imaging

  • Cho, Ah Rang;Lee, Hae Kag;Yoo, Heung Joon;Park, Cheol-Soo
    • Journal of Magnetics
    • /
    • v.20 no.4
    • /
    • pp.381-386
    • /
    • 2015
  • The purpose of this study is to improve diagnostic efficiency of clinical study by setting up guidelines for more precise examination with a comparative analysis of signal intensity and image distortion depending on the location of X axial of object when performing magnetic resonance diffusion weighted imaging (MR DWI) examination. We arranged the self-produced phantom with a 45 mm of interval from the core of 44 regent bottles that have a 16 mm of external diameter and 55 mm of height, and were placed in 4 rows and 11 columns in an acrylic box. We also filled up water and margarine to portrait the fat. We used 3T Skyra and 18 Channel Body array coil. We also obtained the coronal image with the direction of RL (right to left) by using scan slice thinkness 3 mm, slice gap: 0mm, field of view (FOV): $450{\times}450mm^2$, repetition time (TR): 5000 ms, echo time (TE): 73/118 ms, Matrix: $126{\times}126$, slice number: 15, scan time: 9 min 45sec, number of excitations (NEX): 3, phase encoding as a diffusion-weighted imaging parameter. In order to scan, we set b-value to $0s/mm^2$, $400s/mm^2$, and $1,400s/mm^2$, and obtained T2 fat saturation image. Then we did a comparative analysis on the differences between image distortion and signal intensity depending on the location of X axial based on iso-center of patient's table. We used "Image J" as a comparative analysis programme, and used SPSS v18.0 as a statistic programme. There was not much difference between image distortion and signal intensity on fat and water from T2 fat saturation image. But, the average value depends on the location of X axial was statistically significant (p < 0.05). From DWI image, when b-value was 0 and 400, there was no significant difference up to $2^{nd}$ columns right to left from the core of patient's table, however, there was a decline in signal intensity and image distortion from the $3^{rd}$ columns and they started to decrease rapidly at the $4^{th}$ columns. When b-value was 1,400, there was not much difference between the $1^{st}$ row right to left from the core of patient's table, however, image distortion started to appear from the $2^{nd}$ columns with no change in signal intensity, the signal was getting decreased from the $3^{rd}$ columns, and both signal intensity and image distortion started to get decreased rapidly. At this moment, the reagent bottles from outside out of 11 reagent bottles were not verified from the image, and only 9 reagent bottles were verified. However, it was not possible to verify anything from the $5^{th}$ columns. But, the average value depends on the location of X axial was statistically significant. On T2 FS image, there was a significant decline in image distortion and signal intensity over 180mm from the core of patient's table. On diffusion-weighted image, there was a significant decline in image distortion and signal intensity over 90 mm, and they became unverifiable over 180 mm. Therefore, we should make an image that has a diagnostic value from examinations that are hard to locate patient's position.