• 제목/요약/키워드: BEM analysis

Search Result 320, Processing Time 0.025 seconds

Electric Field Distribution of XLPE due to Position of Void (보이드 위치에 따른 XLPE 전계분포)

  • Park, Hyoung-Jun;Kim, G.S.;Shin, H.T.;Lee, J.P.;Kim, G.Y.;Lee, S.W.;Hong, J.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2003.11a
    • /
    • pp.220-223
    • /
    • 2003
  • This paper is aimed at determining the e-field distribution by apply voltage of air void, which can be generate air void in the XLPE cable for ultra high voltage. E-field distribution had an effect in XLPE due to the type and position of void, compared and studied. This method of analysis is based on the quasi-static electromagnetic 3D simulation program by boundary element method (BEM): Applied AC 3[kV], discretization of 2000 elements, 4 angular periodicity, The result of experiment indicate that E-field distribution appeared the highest levels on the void position of electrode 2[nm] outer boundary and shape of the smallest inner angle in the void. This will serve to explain the XLPE cable degradation studied of possible, connected cable variation of position and shape of void effects to e-field concentration.

  • PDF

Development of Korean Gender Role Identity Inventory (한국인의 성역할 정체감 검사 도구 개발)

  • 이병숙;김명애;고효정
    • Journal of Korean Academy of Nursing
    • /
    • v.32 no.3
    • /
    • pp.373-383
    • /
    • 2002
  • This study was performed to develope a scale of gender role identity in Korean adults based on the Bem's theory of androgyny. Although there were several tools in Korea, they were revealed having some problems of cultural differences, translation biases, and methodological problems. Methods: A list of 78 items were developed using the existing tools and descriptions from 5 married couples. The items were the typical personality characteristics which were manifested by gender, male or female. And the list contained several items which were the socially desirable personality characteristics. which would be simply used as contextual items. Validity of the 78 items were screened by 18 expert panels with 4 point Likert scale, and 57 items were judged as highly valid from 70% of the experts, which were selected as preliminary items for the tool. Using the preliminary tool which was developed as a 4 point Likert scale, data were collected from 1,127 subjects for item analysis and factor analysis. 53 items were remained, because 4 items whose item-total correlation were lower than 0.2 were excluded by the result of item analysis. Factor analysis was done with the 53 items, and 49 items whose factor loadings were same and higher than 0.4 were remained. 3 factors were identified with eigen value 2.0, and these factors were named as masculinity, femininity, and social desirability. Results and Conclusion: KGRII(Korean Gender Role Identity Inventory) which contained 45 items was developed, with 15 items for 3 factors. The reliability of the tool was very high. Cronbach alpha of the tool was 0.929, and alpha of the subscales were ranged from 0.841 to 0.922.

The Relationships between Sex-Role Identity and Yin-Yang Clothing Behavior of Mothors and Daughters (어머니와 딸의 성역할 정체감과 음양의복행동간의 관계)

  • Lee Hyun My;Lim Sook Ja
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.11 no.3 s.25
    • /
    • pp.67-77
    • /
    • 1987
  • The purposes of this study were to investigate the relationship between mothers and daughters in sex-role identity and yin-yang clothing behavior as well as the relationship between sex-role indentity and yin-yang clothing behavior Sex-role identy was measured by Bem Sex-Role Inventory (1974) modified and supplemented for this study. For the measurement of yin-yang clothing behavior, researcher developed a questionnaire. Data were collected from 422 women, both college women and her mothers. For the statistical analysis, frequency, distribution, t-test, one-way analysis of variance, Duncan's multiple range test, $x^2-test$, Pearson's correlation coefficients, analysis of covariance. multiple regression analysis were used. The results of this research can be summarized as follows: 1 There was significant difference in yin-yang clothing behavior according to home environmental variables such as family type, mother's employment. 2. There was not significant difference in mother's yin-yang clothing behavior according to mother's sex-role identity. But positive significant relationship was found between daughter's sex-role identity and daughter's yin-fang clothing behavior. 3. Mother's sex-role identity had influence on daughter's sex-role identity And mother's yin-yang clothing behavior had influence on daughter's yin-yang clothing behavior, too. 4. Mother's fin-yang clothing behavior and daughter's sex-role identity directly affected daughter's yin-yang clothing behavior, but mother's sex-role identity indirectly affected daughter's yin-yang clothing behavior.

  • PDF

Structural Analysis of Floating Offshore Wind Turbine Tower Based on Flexible Multibody Dynamics (탄성 다물체계 동역학을 기반으로 한 부유식 해상 풍력 발전기 타워의 구조 해석)

  • Park, Kwang-Phil;Cha, Ju-Hwan;Ku, Namkug;Jo, A-Ra;Lee, Kyu-Yeul
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.36 no.12
    • /
    • pp.1489-1495
    • /
    • 2012
  • In this study, we perform the structural analysis of a floating offshore wind turbine tower by considering the dynamic response of the floating platform. A multibody system consisting of three blades, a hub, a nacelle, the platform, and the tower is used to model the floating wind turbine. The blades and the tower are modeled as flexible bodies using three-dimensional beam elements. The aerodynamic force on the blades is calculated by the Blade Element Momentum (BEM) theory with hub rotation. The hydrostatic, hydrodynamic, and mooring forces are considered for the platform. The structural dynamic responses of the tower are simulated by numerically solving the equations of motion. From the simulation results, the time history of the internal forces at the nodes, such as the bending moment and stress, are obtained. In conclusion, the internal forces are compared with those obtained from static analysis to assess the effects of wave loads on the structural stability of the tower.

An analysis of the relationship between Sex-role-identity and life adjustment among adult patients perceives (성인환자가 지각한 성역할 정체감과 생활적응과의 관계분석)

  • 모경빈
    • Journal of Korean Academy of Nursing
    • /
    • v.18 no.3
    • /
    • pp.245-256
    • /
    • 1988
  • The purpose of this study was to examne the relationship between sex-role-identity and life adjustment which adult patients perceive by means of the analysis of the relationship between the sex-role-identity and life adjustment which are perceived by adult patients who are hospitalized. The primary purpose of this study is to investigate how the adult patients describe their own Sex role-identity. Sceondary purpose is to find out whether their Sex role-identity is related to life adjustment and which life circumstances. If any are associated with Sex role identity. 207 adult patients who were older than 30 years living under 65 years were admitted to the hospital in Seoul. Were interviewed with measures including the Bem Sex Role Inventory short Form. Life adjustment and current life situation. For data analysis, X$^2$-test, ANOVA, and Scheffe test were used. The results are summarized as follows ; (1) Most adult patients described androgynous Sex role-identity. (2) Sex role-identity differentiated significantly life adjustment. (3) Perceived Sex role identity was related to the Several dimension of life sityation such as marital status family construction activity. By the result of this study, the present writer is to suggest as follows ; Firstly, in the aspect of the study of nursing the many -sided and desirable study on the relation between the sex-role-identity life ajustment, and the study which a nurse can control and prevent the anxiety of adult patients by means of examining the measure and the cause of the emotional support on a patient must be accomplished. Secondly, in the aspect of the aspect of the practical affairs of nursing the practical effort which puts emphasis on the whole personal nursing in the performance of the duty, and the institutional support in the nursing administration must be planned in order to increase the efficiency of the nursing service by promoting the whole -personal nursing role of a nurse.

  • PDF

Two Dimensional Flexible Body Response of Very Large Floating Structures (거대 부체구조물의 2차원 유연체 해석 및 거동)

  • Namseeg Hong
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.8 no.4
    • /
    • pp.274-286
    • /
    • 1996
  • Two-dimensional flexible body analysis (hydroelasticity theory) is adopted to a very large floating structure that may be multimodule and extend in the longitudinal direction. The boundary-element method (BEM) and Green function method(GFM) are used to obtain the hydrodynamic coefficients. The structure is considered to be a flexible beam responding to waves in the vertical direction and a consistent formulation for the hydrostatic stiffness is derived. The resulting coupled equations of motion are solved directly. Two designs of the module connectors are considered: a rotationally-flexible hinge connector, and a rotationally-rigid connector Numerical examples are presented to an integrated system of semi-submersibles. The analysis provides basic motions and section forces, which are useful to develop an understanding of the fundamental modes of displacement and force amplitudes for which multi-module VLFSs must be designed. The results show that while the hinge connectors result in greater motion, the rigid connectors increase substantially the sectional moments.

  • PDF

Optimum design of injection molding cooling system via boundary element method (경계요소법을 이용한 사출성형금형 냉각시스템의 최적설계)

  • Park, Seong-Jin;Kwon, Tai-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.11
    • /
    • pp.1773-1785
    • /
    • 1997
  • The cooling stage is the very critical and most time consuming stage of the injection molding process, thus it cleary affects both the productivity and the part quality. Even through there are several commercialized package programs available in the injection molding industry to analyze the cooling performance of the injection molding coling stage, optimization of the cooling system has npt yet been accomplished in the literature due to the difficulty in the sensitivity analysis. However, it would be greatly desirable for the mold cooling system designers to have a computer aided design system for the cooling stage. With this in mind, the present study has successfully developed an interated computer aided design system for the injection molding cooling system. The CAD system utilizes the sensitivity analysis via a Boundary Element Method, which we recently developed, and the well-known CONMIN alforuthm as an optimization technique to minimize a weighted combination (objective function) of the temperature non-uniformity over the part surface and the cooling time related to the productivity with side constranits for the design reality. In the proposed objective function , the weighting parameter between the temperature non-uniiformity abd the cooling time can be adjusted according to user's interest. In this cooling system optimization, various design variable are considered as follows : (i) (design variables related to processing conditions) inlet coolant bulk temperature and volumetric flow rate of each cooling channel, and (ii) (design variables related to mold cooling system design) radius and location of each cooling channel. For this optimum design problem, three different radius and location of each cooling channel. For this optimum design problem, three different strategies are suffested based upon the nature of design variables. Three sample problems were successfully solved to demonstrated the efficiency and the usefulness of the CAD system.

Optimum mesh size of the numerical analysis for structural vibration and noise prediction (구조물 진동.소음의 수치해석시 최적 요소크기는 .lambda./4이다.)

  • Kim, Jeung-Tae;Kang, Jun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.11
    • /
    • pp.1950-1956
    • /
    • 1997
  • An engineering goal in vibration and noise professionals is to develope quiet machines at the preliminary design stage, and various numerical techniques such as FEM, SEA or BEM are one of the schemes toward the goal. In this paper, the research has been focused on the sensitivity effect of mesh sizes for FEM application so that the optimum size of the mesh that leads to engineering solution within acceptable computing time could be generated. In order to evaluate the mesh size effect, three important parameters have been examined : natural frequencies, number of modes and driving point mobility. First, several lower modes including the fundamental frequency of a 2-D plate structure have been calculated as mesh size changes. Since theoretical values of natural frequencies for a simple structure are known, the deviation between the numerical and theoretical values is obtained as a function of mesh size. The result shows that the error is no longer decreased if the mesh size becomes a quarter wavelength or smaller than that. Second, the mesh size effect is also investigated for the number of modes. For the frequency band up to 1.4 kHz, the structure should have 38 modes in total. As the mesh size reaches to the quarter wavelength, the total count in modes approaches to the same values. Third, a mobility function at the driving point is compared between SEA and FEM result. In SEA application, the mobility function is determined by the modal density and the mass of the structure. It is independent of excitation frequencies. When the mobility function is calculated from a wavelength to one-tenth of it, the mobility becomes constant if the mesh becomes a quarter wavelength or smaller. We can conclude that dynamic parameters, such as eigenvalues, mode count, and mobility function, can be correctly estimated, while saving the computing burden, if a quarter wavelength (.lambda./4) mesh is used. Therefore, (.lambda./4) mesh is recommended in structural vibration analysis.

An ex post facto Relational Study of Genderlogy, and Gender Identity of Clothing and Attitudes toward Unisex Clothing -female and male college students in Taejeon, Chungnam, and Chungbuk province- (성역할 개념, 의복 성정체감, 유니섹스 의복에 대한 태도 사이의 상관 연구 -대전, 충남북 지역의 남녀 대학생을 중심으로-)

  • 차진희;김재숙
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.19 no.5
    • /
    • pp.738-746
    • /
    • 1995
  • The purposes of this study were 1) to find out any significant relationships among genderlogy, gender identity of clothing, and attitudes toward unisex clothing, 2) to investi- gate differences in genderlogy, gender identity of clothing, and attitudes toward unisex clothing between female and male college students, 3) to understand the structual dimension of genderlogy. The theory of this study was Bem's androgyny sex role theory which suggested an individual's masculine and feminine sex role lied on separate lines rather than on a linear line. The research design was an ex post facto survey and the subjects were 222 female college students and 179 male students in Taejeon, Chungnam and Chungbuk province. Using the SPSS program, factor analysis, 1-test, Pearson correlation coefficient, and plot were calculated for statistical analysis. The findings of this study were summarized as follows: 1) The 1.test showed significant differences in genderloy, gender identity of clothing, attitudes toward unisex clothing between female and male college students. 2) There were significant relationship among genderlogy, gender identity of clothing, attitudes toward unisex clothing. 3) The moi or dimensions of genderlogy were found to be traditional sex role and equal sex roles. There were only moderate negative relationship between traditional and equal sex roles and these two dimensions affected differently on the gender identity of clothing, as well as the attitudes toward unisex clothing, therefore traditional sex roles and equal sex roles seemed to lie on separate lines, and the androgyny sex role theory was supported.

  • PDF

An Experimental Study on the Noise Reduction of Cooling Fans for Four-ton Forklift Machines (4톤급 지게차 냉각홴 소음 저감에 관한 실험적 연구)

  • Choi, Daesik;Kim, Seokwoo;Yeom, Taeyoung;Lee, Seungbae
    • Journal of Drive and Control
    • /
    • v.18 no.1
    • /
    • pp.1-8
    • /
    • 2021
  • This paper presents research on methods for the reduction of forklifts' noise level for the increased comfort and safety of its operator. A cooling fan with a high air volume flow rate installed in the forklift acts as an important design parameter which efficiently cools the heat exchanger system, helping to transfer internal heat from the engine room to the outdoors with both transmitted and diffracted opening noises. The cooling fan contributes significantly to both the forklift's emitted sound power and the operator room's noise level, thereby necessitating research on the forklift's reduction of acoustic power level and transmission. A noise analysis for various fan models with a biomimetic design based on eagle-wing geometry was conducted. In addition to the acoustic power generation, the aerodynamic performance of the cooling blade is also strongly influenced by the design of airfoil distribution, thereby requiring optimization. The cooling fans were fabricated and installed in the forklift in order to check the efficacy of the forklift engine's cooling, and the final version of the fan was measured for its ability to lower acoustic power level and cool the engine room. This study explains the aerodynamic and acoustic features of the designed fans with the use of BEM analysis and forklift test results.