• Title/Summary/Keyword: Stiffness Evaluation

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A Study on the Visual Evaluation of Bell Bottom Pants (벨 버텀 팬츠(Bell Bottom Pants)의 시각적 평가)

  • Lee, Jung-Soon
    • Journal of the Korea Fashion and Costume Design Association
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    • v.16 no.1
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    • pp.15-25
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    • 2014
  • The purpose of this study is to recognize the differences of visual evaluation by variations in width of hem line and waistline position of the bell buttom pants. The stimuli are 9 samples: One control group, 3 variations of the width of hem line and 3 variations of the waistline position. The data has been obtained from 56 fashion students. The data has been analyzed by Factor Analysis, Anova, Scheffe's Test and the MCA method. The results of the study are as follows: The visual evaluation by the width of hem line and waistline position of bell buttom pants are composed of 5 factors : comfort, personality, physical characteristics, stiffness and modern. Among these factors, the comfort is evaluated to be the most important factor. As a visual evaluation result of changes in the width of hern line, 62cm in width (the narrowest width) was highly evaluated in comfort and stiffness factors, 78cm in width (the widest width) was highly evaluated in personality and physical characteristics factors. For the result of changes in the waistline position, high-waisted bell buttom pants were was highly evaluated in personality and stiffness factors, low-waisted bell buttom pants were was highly evaluated in comfort, physical characteristics and modern factors. The width of hem line and waistline position of the bell buttom pants interacted to the comfort factor. The width of hem line had more influence on visual evaluation in personality factors while physical characteristics, stiffness and modern factors were affected by the waistline position.

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Evaluation of the Rotational Stiffness of Connections between Vertical and Horizontal Members for the Highly Reusable System Supports (재사용율이 높은 시스템 동바리의 수직재와 수평재 연결부 회전강성 평가)

  • Ji-Sun Park;Tae-Hyeob Song
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.517-526
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    • 2023
  • To avoid arbitrary design and excessive braces of system supports with high reusability in the field, this study aimed to propose connection conditions for the vertical and horizontal joints of the system supports based on performance evaluation. Disk-type and pocket-type connection materials, widely used in domestic construction sites, were selected for evaluation of rotational stiffness based on load directions(vertical and horizontal) and loading methods (monotonic and cyclic). Contrary to the current design standards specifying a rotational stiffness of "0" for connection materials, the experimental results revealed that, contrary to the current design standards specifying a rotational stiffness of "0" for connection materials, all specimens exhibited rotational stiffness values. The maximum rotational stiffness was observed to be 19.624 kNm/rad in specimens subjected to repeated loading in the vertical direction using disk-type connection materials.

The Study of Stiffness Evaluation Technique for L, T Shaped Joint Structures Using Normal Modes Analysis with Lumped Mass (모드해석을 이용한 L, T 자형 구조물의 결합 강성 평가 방법에 대한 연구)

  • Hur, Deog-Jae;Jung, Jae-Yup;Cho, Yeon;Park, Tae-Won
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.975-983
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    • 1999
  • This paper describes the dynamic characteristics of the joint structures in case of using the simplified beam model in the F. E. analysis. The modeling errors, when replace the shell with the beam, are investigated through F. E. normal modes analysis. Normal mode analysis were performed to obtain the natural frequencies of the L and T shaped joints with various type of channels. The results were analyzed to access the effects of the models on the accuracy of F.E. analysis by identifying the geometric factors which cause the error. The geometric factors considered are joint angle, channel length, thickness and area ratio of the hollow section to the filled one. The joint stiffness evaluation technique is developed in this study using normal modes analysis with Lumped Mass. With this method, the progressively improved results of F. E. analysis are obtained using the simplified beam model. The static and normal modes analysis are performed with the joint stiffness values obtained by the Kazunori Shimonkakis' virtual stiffness method and the proposed method and these simplified modeling errors are compared.

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The Static and Dynamic Analysis of a 45,000rpm Spindle for a Machine Tool and Evaluation of Its Stiffness (공작기계용 45,000rpm 주축의 정.동적 해석과 강성평가)

  • Kim, Dong-Hyeon;Lee, Choon-Man
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.4
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    • pp.422-426
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    • 2011
  • The spindle system is very important unit for the product accuracy in machine tools. A spindle system is designed by using the angular contact ceramic ball bearings, built-in motor, oil-air lubrication method and oil jacket cooling method. The static and dynamic analysis and stiffness evaluation of 45,000rpm spindle for machine tool has been investigated. Using a finite element method, we obtained some analyzed a static and dynamic characteristics of a spindle, such as natural frequency, harmonic analysis and we got the value of compliance through it. We evaluated stiffness by taking the inverse this value. A 45,000rpm spindle is successfully developed using the results.

Development and Performance Evaluation of In-situ Dynamic Stiffness Analyzer (원위치 동적강성 분석기의 개발 및 성능평가)

  • Kim, Dong-Ju;Byun, Yong-Hoon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.61 no.2
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    • pp.41-50
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    • 2019
  • Stiffness characteristic of subgrade is one of the most important aspects for the design and evaluation of pavement and railway. However, adequate field testing methods for evaluating the stiffness characteristics of the subgrade have not been developed yet. In this study, an in-situ dynamic stiffness analyzer (IDSA) is developed to evaluate the characteristics of subgrade stiffness along the depth, and its performance is evaluated in elastic materials and a compacted soil. The IDSA consists of a falling hammer system, a connecting rod, and a tip module. Four strain gauges and an accelerometer are installed at the tip of the rod to analyze the dynamic response of the tip generated by the drop of hammer. Based on the Boussinesq's method, the stiffness and Young's modulus of the specimens can be calculated. The performance of IDSA was tested on three elastic materials with different hardness and a compacted soil. For the repeatability of test performance, the dynamic signals for force and displacement of the tip are averaged from the hammer impact tests performed five times at the same drop height. The experimental results show that the peak force, peak displacement, and the duration depend on the hardness of the elastic materials. After calculating the stiffness and elastic modulus, it is revealed that as the drop height of hammer increases, the stiffness and elastic moduli of MC nylon and the compacted soil rapidly increase, while those of urethanes less increase.

An effective evaluation method for the subjective sensibility of linen-like silk (의마 가공된 견직물의 효율적인 주관적 감성평가 방법)

  • You, Ji-Ho;Lee, Jung-Soon
    • Korean Journal of Human Ecology
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    • v.15 no.3
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    • pp.439-447
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    • 2006
  • The purpose of this study is to explore the accuracy and reliability of subjective evaluation instruments in evaluating sensibility of similar fabrics, Kendall's coefficient of concordance W (agreement among subjects) and Spearman rank correlation coefficient (reproducibility after 1 week) were used to evaluate which one is more efficient. Eight kinds of linen-like silk fabrics finished with polyurethane resin were used, Subjective evaluation instruments such as rating scale method, contrasting method against a control, rank ordering method, paired comparison and Quad analysis were used, 'Stiffness and Pliability' and 'Preference of summer fabric' were estimated, From the result of subjective stiffness and pliability, which are effective on objective properties of fabric, the rating scale method in Kendall's coefficient of concordance W and Quad analysis in Spearman rank correlation coefficient were given the highest score, From the result of subjective preference of summer fabric, which are effective on individual sensibility, contrasting method against a control in Kendall's coefficient of concordance W and Quad analysis in Spearman rank correlation coefficient revealed the highest score, Regarding the accuracy, reliability and efficiency, Quad analysis was an efficient method for subjective evaluation of linen-like silk fabrics.

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A Study on the Visual Evaluation According to Changes in Width of Hem Line and Waistline Position of Flare Pants (플레어 팬츠의 바지부리 폭과 허리선 위치의 변화에 따른 시각적 평가)

  • Lee, Jung-Soon
    • Journal of the Korea Fashion and Costume Design Association
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    • v.14 no.4
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    • pp.127-137
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    • 2012
  • The purpose of this study is to recognize the differences of visual evaluation by variations in width of hem line and waistline position of the flare pants. The stimuli are 9 samples: One control group, 3 variations of the width of hem line and 3 variations of the waistline position. The data has been obtained from 44 fashion students. The data has been analyzed by Factor Analysis, Anova, Scheffe's Test and the MCA method. The results of the study are as follows: The visual evaluation by the width of hem line and waistline position of flare pants are composed of 5 factors : physical characteristics, elegance, originality, comfort, and stiffness. Among these factors, the physical characteristic is evaluated to be the most important factor. As a v isual evaluation result o f changes in the width o f hern l ine, 8 4 cm in width (the narrowest width) was highly evaluated in physical characteristics, elegance, and originality factors. For the result of changes in the waistline position, high-waisted flare pants were highly effective in physical characteristics, and also evaluated well in elegance, originality and stiffness factors. The flare pants did not show any interaction between the width of hem line and waistline position. The waistline position had more influence on visual evaluation in physical characteristics, originality and comfort factors while elegance and stiffness factors were affected by the width of hem line.

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Stress Evaluation and Case Study of Reinforced Wall-thinned Class 2 and 3 Pipes in Operating Nuclear Power Plants Using Equivalent Stiffness Concept (등가 강성 개념을 이용한 가동 원전 2, 3등급 감육 보강 배관의 응력 평가 및 사례해석)

  • Xinyu Ma;Jae Yoon Kim;Jin Ha Hwang;Yun Jae Kim;Man Won Kim
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.18 no.2
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    • pp.54-60
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    • 2022
  • ASME BPVC provides stress evaluation rules for Class 2 and 3 nuclear piping. However, such rules are difficult to be applied to reinforced wall-thinned pipes during service. To resolve this issue, a new method for stress evaluation of reinforced wall-thinned pipes is proposed in this work, based on the equivalent stiffness concept. By converting a reinforced wall-thinned pipe to an equivalent straight pipe having the same stiffness, stress evaluation can be proceeded using the current ASME BPVC rules. The proposed method is applied to pipes with 4 different normal pipe size and the effects of reinforcement and wall-thinning dimensions on evaluated stresses are discussed.

Evaluation of Subgrade Stiffness using Pressuremeter Test (공내재하시험에 의한 포장하부기초 강성도 평가)

  • Lim, Yu-Jin;Hai, Nguyen Tien;Jang, Duk-Sun
    • International Journal of Highway Engineering
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    • v.6 no.2 s.20
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    • pp.25-36
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    • 2004
  • The pressuremeter test can be used as an effective tool for evaluating stiffness of lower pavement layers including subgrade and subbase. At present, the most practical and applicable methods for evaluation of the stiffness of the subgrade and subbase are PBT and CBR in Korea. However, these methods have inherent drawbacks and large variabilities of test results themselves. In this study, an evaluation method and a test procedure that can be used for decision of pavement stiffness using pressuremeter were developed. The obtained results representing stiffness of the subgrade and subbase can replace PBT's soil reaction value k and CBR in design methods. It is found that the developed procedure based on the pressuremeter can provide an effective correaltion between the PBT's soil reaction value k and PMT's reloading modulus ($E_R$).

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Evaluation on the Edge Stiffening Affect of Composite Girder Bridge (합성형교의 외측강성 영향 평가)

  • Sung, Ki Tae;Park, Young Hoon;Lee, Seung Yong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.2A
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    • pp.179-186
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    • 2008
  • To analyzing the validity for using the stiffness ratio in evaluating edge stiffness effect of the composite girder bridges, modification factors are analyzed with changing girder spacing. The relation between stiffness ratio, loading type, girder spacing and modification factors is analyzed. From the results of comparing modification factors analyzed from the field loading test and the established design method with the modification factor analyzed from this study, it was concluded that evaluating the edge stiffness effect using stiffness ratio is possible.