• Title, Summary, Keyword: modification factor

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Evaluation of Stress Intensity Factor after Penetration of Plate with Long Surface Crack (긴 표면균열재의 관통후 응력확대계수 평가)

  • Nam Kiwoo;Lee Jongrark
    • Journal of the Korean Institute of Gas
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    • v.4 no.1
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    • pp.33-39
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    • 2000
  • Stress intensity factor after penetration was discussed experimentally using long surface pre-cracked specimens of aluminum alloy 5083. The propagation behavior evaluation of long surface crack by equation proposed at penetration of short surface crack could be need modification to evaluate precisely because the error was high as aspect ratio is little. The modification of stress intensity factor with consideration of aspect ratio at penetration of long surface crack can be analyzed the behavior of crack penetration quantitatively.

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A study on strength of internal gear (내접치차의 강도에 관한 연구)

  • 정태형
    • Journal of the korean Society of Automotive Engineers
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    • v.6 no.3
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    • pp.45-54
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    • 1984
  • Bending strength of an internal gear tooth is discussed as tooth form factor taking into account the actual stress magnitude. Stress analysis was carried out by the finite element method(FEM) for the calculation of tooth form factor of an internal gear. This paper also investigated the influences of number of teeth and addendum modification coefficient of the internal gear and the influences of number of teeth, addendum modification coefficient, pressure angle, radius of rounding of tooth tip, and bottom clearance coefficient of the pinion-shaped cutter on tooth form factor of internal gear. Generalizing the resultant data, a simple formula for the tooth form factor of an internal gear was derived for the calculation of tooth bending strength of an internal gear.

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Evaluation of Ductility and Strength Factors for Special Steel Moment Resisting Frames (철골 연성 모멘트 골조의 연성계수 및 강도계수 평가)

  • Kang, Cheol Kyu;Choi, Byong Jeong
    • Journal of Korean Society of Steel Construction
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    • v.16 no.6
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    • pp.793-805
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    • 2004
  • The main objective of this paper is to evaluate the ductility and strength factors that are key components of the response modification factor for special steel moment-resistant frames. The ductility factors for special steel moment-resistant frames were calculated by multiplying the ductility factor for SDOF systems and the MDOF modification factors. Ductility factors were computed for elastic and perfectly plastic SDOF systems undergoing different levels of inelastic deformation and periods when subjected to a large number of recorded earthquake ground motions. Based on the results of the regression analysis, simplified expressions were proposed to compute the ductility factors. Based on previous studies, the MDOF modification factors were also proposed to account for the MDOF systems. Strength factors for special steel moment resisting frames were estimated from the results of the nonlinear static analysis. A total of 36 sample steel frames were designed to investigate the ductility and strength factors considering design parameters such as number of stories (4, 8, and 16 stories), seismic zone factors (Z = 0.075, 0.2, and 0.4), framing system (Perimeter Frames, PF and Distributed Frames, DF), and failure mechanism (Strong-Column Weak Beam, SCWB, and Weak-Column Strong-Beam, WCSB). The effects of these design parameters on the ductility and strength factors for special steel moment-resisting frames were investigated.

Investigation on Response Modification Factor of RC Structural Walls in Apartment Buildings (아파트 건물의 구조 벽체에 대한 반응수정계수)

  • 한상환;오영훈;이리형
    • Journal of the Korea Concrete Institute
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    • v.13 no.6
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    • pp.544-552
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    • 2001
  • Korea is classified into low and moderate seismic zone from the view-point of seismic hazard level. Korean seismic provisions has been developed based on UBC and ATC 3-06. Thus, in calculation of design base shear according to Korean provisions response modification factor (R) is included in the formula of design base shear. The major role of this factor is to reduce the elastic design base shear whereby structures can behave in inelastic range during design level earthquake ground motions(mean return period of 475 yrs.). R factor is assigned according to material and structural systems. In this study, R factor for bearing wall system is considered. Most of the walls of apartment buildings in Korea resist gravity and seismic loads simultaneously so that this wall system can be classified into bearing wall system. Structural details of these walls are different from those used in Japan and U.S.. They are all rectangular in sectional shape rather than barbell in shape, and also have special lateral reinforcement details at the boundaries of a wall. In Korean seismic design provisions(1988), two different values(3.0 and 3.5) of R factor are assigned to the bearing wall systems according to the wall details. However, in updated seismic provisions(2000), only one value is assigned to R factor(3.0) irrespective of wall details. In this study, the design base shear values in Korean seismic design provisions(1988, 2000), ATC 3-06, UBC are compared. Also experimental study was carried out to evaluate the seismic performance of structural walls. For this purpose, five test specimens were made which have special details used in apartment bearing wall systems in Korea. Based on the results of this study, response modification factor for bearing wall system is discussed.

Response Modification Factors of Inverted V-type Special Concentrically Braced Frames (역V형 특수가새골조의 반응수정계수)

  • 김진구;남광희
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.1
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    • pp.29-37
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    • 2004
  • The overstrength factor and the ductility factor are the two important factors that determine response modification factors used in current seismic codes, In this paper the overstrength and ductility factors of special concentric braced frames are determined by performing pushover analysis of model structures with various stories and span lengths. and by using those factors the response modification factors are obtained. According to the analysis results. the overstrength and the ductility factors are larger than the values proposed by the codes in low-rise structures. and the opposite is true in medium to high-rise structures, It is also found that the factors increase as the height of structures decreases and the span length increases.

Energy-based design base shear for RC frames considering global failure mechanism and reduced hysteretic behavior

  • Merter, Onur;Ucar, Taner
    • Structural Engineering and Mechanics
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    • v.63 no.1
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    • pp.23-35
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    • 2017
  • A nonlinear static procedure considering work-energy principle and global failure mechanism to estimate base shears of reinforced concrete (RC) frame-type structures is presented. The relative energy equation comprising of elastic vibrational energy, plastic strain energy and seismic input energy is obtained. The input energy is modified with a factor depending on damping ratio and ductility, and the energy that contributes to damage is obtained. The plastic energy is decreased with a factor to consider the reduced hysteretic behavior of RC members. Given the pre-selected failure mechanism, the modified energy balance equality is written using various approximations for modification factors of input energy and plastic energy in scientific literature. External work done by the design lateral forces distributed to story levels in accordance with Turkish Seismic Design Code is calculated considering the target plastic drift. Equating the plastic energy obtained from energy balance to external work done by the equivalent inertia forces considering, a total of 16 energy-based base shears for each frame are derived considering different combinations of modification factors. Ductility related parameters of modification factors are determined from pushover analysis. Relative input energy of multi degree of freedom (MDOF) system is approximated by using the modal-energy-decomposition approach. Energy-based design base shears are compared with those obtained from nonlinear time history (NLTH) analysis using recorded accelerograms. It is found that some of the energy-based base shears are in reasonable agreement with the mean base shear obtained from NLTH analysis.

Experimental Evaluation of Seismic Performance Factors for Tall Diagrid Structure (초고층 다이아 그리드 구조의 실험적 내진성능계수 평가)

  • Bae, Jae-Hoon;Ju, Young-Kyu;Kim, Young-Ju;Kim, Sang-Dae
    • Journal of Korean Society of Steel Construction
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    • v.22 no.1
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    • pp.75-85
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    • 2010
  • A new freeform structure representing "Diagrid, Cantilevered, Tilted." which has been considered not only its distinctive appearance but also the structural advantages becomes one of the trends in tall building design. Especially in the Diagrid system, loads can be distributed through bracing frame so that it can be save the materials since it has more effective in the structure behavior. But the seismic performance index such as response modification factor is not clearly defined yet. Even though the diagrid is supposed to show higher seismic performance, it is underestimated due to the lack of reliable data. In this paper the response modification factor for the diagrid system is experimentally explored.

Effect of Design Modification and Color Scheme on Impression Formation of Traditional Korean Women's Clothing (여자한복의 인상형성 연구 - 디자인의 변형과 배색을 중심으로 -)

  • Kahng Hewon;Koh Ae Ran
    • Journal of the Korean Society of Clothing and Textiles
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    • v.15 no.2
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    • pp.211-227
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    • 1991
  • The purpose of this study was to investigate the effects of design modification, decoration and color scheme of traditional Korean women's clothing on impression formation by 2 age groups of women. The instruments developed for the study were 2 sets of stimuli and a response scale. Stimuli I (design stimuli) consisted of 6 line drawings of female figures in Korean clothing and modified Korean style clothing, whereas stimuli II (color stimuli) consisted of 6 colored drawings of female figures in different color schemes. The 7-point semantic differential scale of 14 bipolar adjectives were used for the response scales. 144 female college students and 144 middle·aged women subjects were randomly assigned to one of 6 drawings from each set of stimuli. The data were analyzed by factor analysis, ANOVA and t-test. 1) There factors emerged to account for dimensions of design and color scheme, respectively. The first factor was interpreted as Evaluation/prestige both in design (stimuli I) and color scheme (stimuli II), the second factor was Modernity for stimuli I, and the third factor for stimuli I was Practicality. On the other hand, the Luxuriousness/Individuality was factor 2 and Modernity was factor 3 for stimuli ll. 2) Modification had the largest effect on impressions regarding design and decorated designs had a partial effect on the impression of Modernity and Practicality. The female figures in modified Korean style clothing were perceived as more prestigious, modern and practical than those in traditional Korean clothing. 3) Color schemes had little effect on impressions, while perceiver's age had a larger effect. Middle·aged women formed more positive impressions toward Korean clothing of various color schemes than female college students.

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The Response Modification Factor of Inverted V-type Braced Steel Frames (역V형 가새골조의 반응수정계수)

  • Ahn, Hyung Joon;Jin, Song Mei
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.1
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    • pp.1-9
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    • 2013
  • In this study of Eccentric Braced Frames have identified the following target eccentricity on the length of the inelastic behavior of the reaction by calculating the correction factor by comparing it to the value suggested by the earthquake provided material for the rational design aims to There are. As a variable-length V-braced frame analysis model stations were set up. Eccentricity faults in the model according to the length stiffness ratio, the maximum amount of energy dissipation were analyzed base shear and multi-layered model of the reaction from the eccentricity correction factor calculated on the length of the building standards proposed by KBC 2009 in response eccentricity correction factor calculated from The length varies. does not have the same response modification factor was confirmed.

Behavior Factor of a Steel Box Bridge with Single Column Piers (단주교각 강박스교량의 거동계수)

  • 박준봉;김종수;국승규
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.228-235
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    • 2002
  • As the response spectrum method generally used in the earthquake resistant design is a linear method, the nonlinear behavior of a structure is to be reflected with a specific factor. Such factors are provided in the "Design Criteria for Roadwaybridges"as response modification factors and in the Eurocode 8, Part 2 as behavior factors. In this study a 5-span steel box bridge with single column piers is selected and the behavior factor is determined. The linear time history analyses are carried out with a simple linear model, where the nonlinear behavior of piers leading to the ductile failure mechanism is considered as predetermined characteristic curves.

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