• Title/Summary/Keyword: deflection test

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A Study on the Seamless Knitting Method of Knitted Flare Skirts (니트 플레어 스커트의 무봉제형 편성 방법에 관한 연구)

  • Ki, Hee-Sook;Lee, Youn-Hee;Park, Myung-Ja;Suh, Mi-A
    • The Research Journal of the Costume Culture
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    • v.16 no.3
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    • pp.425-431
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    • 2008
  • The purpose of this study was to observe the changes of skirt length of knitted flare skirts when the seamless test garments were made which had been having full shape while being knitted and to change and amend the challenges in advance when those were knitted. For this study, I made 6 kinds of knitted test garments of wool 100% yarn with seamless knitting machine, which differed from each other by skirt angles ($90^{\circ},\;180^{\circ}$) and gauges (7G, 12G, 15G), and then I measured deflection changes of their length for 2 weeks. Findings and conclusions drawn from this study were as follows: First, the side seam line of full shape hecame somewhat longer than center. Second, 7G and $180^{\circ}$ knitted flare skirt showed the biggest length deflection changes. Third, there was no difference at rear waist deflection changes between front pattern and rear. Fourth, it was difficult to control the tensions of right and left strings as to the knitting directions.

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Deflection Behavior of Concrete Members Reinforced with FRP Bars (FRP-보강근 콘크리트 부재의 처짐 거동)

  • Choi, Bong-Seob
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.2
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    • pp.936-943
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    • 2011
  • The effective moment of inertia revising the expression proposed by Branson has been used in ACI 440.1R-06 design guide for calculating deflections of FRP-reinforced concrete members. However, its adequacy has been questioned by several researchers. The propose of this study is to provide fundamental data for the rational design of deflection by the comparison of the experimental results obtained from twelve specimens with rectangular section and nine specimens with T-shaped section to the theoretical results. As a result, it found that calculated results for specimens with rectangular section were underestimated comparing to test results, while calculated results for specimens with T-shaped section were overestimated comparing to test results.

An Experimental Study on Characteristic Analysis of Deflection Response of RC Structures using Measured Strain (측정변형률을 이용한 RC 구조물의 변위 응답 특성분석에 관한 실험적 연구)

  • Park, Hung-Seok;Park, Ki-Tae;Lee, Kyu-Wan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.3
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    • pp.173-180
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    • 2001
  • In the past few years, the nondestructive inspection technology has greatly developed due to the increased necessity to gain a complete understanding of the bridge behavior. Especially, the deformations of bridges contain a lot of informations about its health state. By measuring these deformations it is possible to analyze the loading and aging behavior of the structure. However, the current, methods (such as LVDT, dial gage, optical displacement transducer, etc) are often of changeable application on site and have the limitations of installation. In this paper, the classical beam theory was reviewed and the deflections of structure are estimated using measured strain which is easy to acquire. The applicability of this algorithm is verified by laboratory(simple reinforced concrete beam) and field test. By this test, we proposed correction factor to estimate deflection of reinforced concrete beam after cracking, and analyze about the generation of correction factor. Also fiber optic sensors as well as resistive strain gages were installed in the concrete beams to establish the applicability of fiber optic sensors in the field of civil engineering.

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Design of Bumper Backbeam Center Reinforcement Bracket for IIHS Full Overlap Bumper Test (IIHS 풀 오버랩 범퍼 시험 대응 범퍼 백빔 중앙 보강재 설계)

  • Kang, Sungjong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.1
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    • pp.105-111
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    • 2015
  • Since 2007, Insurance Institute of Highway Safety(IIHS) has conducted the new bumper test using bumper barrier to estimate the repair cost of impacted vehicle. In this study, for the front body FE model of a medium size passenger car analyzes were carried out to optimize the shape of backbeam center reinforcement bracket. First, overlap effect was examined with changing the overlap magnitude and spot welds were added along the backbeam center line for reducing the section shear deformation. Next, for an overlap model design parameter study was performed for the bracket. Thickness effect was examined and an inner reinforcement was added to the bracket. Also, the lower part of bracket was deleted and additionally the bracket length was extended. The results were discussed in terms of backbeam backward deflection, barrier backstop intrusion and weight. Compared with the current design, the final model showed 44.1% bracket weight reduction with 30.0% decrease of backbeam deflection.

Test and analysis of concrete-filled double steel and double skin tubular columns having outer stainless steel tube

  • Tokgoz, Serkan;Karaahmetli, Sedat;Dundar, Cengiz
    • Steel and Composite Structures
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    • v.45 no.1
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    • pp.23-38
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    • 2022
  • This paper presents experimental and analytical studies of eccentrically loaded concrete-filled double steel (CFDST) and concrete-filled double skin tube (DCFST) columns having outer stainless steel tube. Eighteen CFDST and DCFST column specimens were manufactured and tested to examine the strength and load-deflection responses. In the study, the main parameters were concrete strength, load eccentricity, cross section and slenderness. The strengths, load-deflection diagrams and failure patterns of the columns were observed. In addition, the tested CFDST and DCFST columns were analyzed to attain the capacity and load versus lateral deflection responses. The obtained theoretical results were compared with the test results. A parametric study was also performed to research the effects of the ratio of eccentricity (e/Ho) slenderness ratio (L/r), Ho/to ratio, Hi/ti ratio and the concrete compressive strength on the behavior of columns. In this work, the obtained results indicated that the ductility and capacity of columns were affected by cross section, concrete strength, steel strength, loading eccentricity and slenderness.

A Study on Shear-Fatigue Behavior of Reinforced Concrete Beams using High Strength Concrete (고강도 콘크리트를 사용한 철근콘크리트 보의 전단피로거동에 관한 연구)

  • 곽계환;박종건
    • Journal of the Korea Concrete Institute
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    • v.11 no.5
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    • pp.119-130
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    • 1999
  • Recently, as the building structure has been larger, higher, longer and more specialized, the demand of material with high-strength concrete for building has been increasing. In this research, silica-fume was used as an admixture in order to get a high-strength concrete. From the test result, High-strength concrete with cylinder strength of 1,200kgf/$\textrm{cm}^2$ in 28-days was produced and tested. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns and fracture modes. The load versus strain and load versus deflection relations were obtained from the static test. The relation of cycle loading to deflections on the mid-span, the crack propagation and the modes of failure according to cycle number, fatigue life and S-N curve were observed through the fatigue test. Based on the fatigue test results, high-strength reinforced concrete beams failed to 57~66 percent of the static ultimate strength. Fatigue strength about two million cycles from S-N curves was certified by 60 percent of static ultimate strength.

A Study on the Manufacturing of Cellular RubBer Products with NR, SBR, NBR EPDM EPDM (NR, SBR, NBR 및 EPDM 발포(發泡)고무의 제조연구(製造硏究))

  • Choi, Sei-Young;Paik, Nam-Chul
    • Elastomers and Composites
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    • v.16 no.1
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    • pp.3-13
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    • 1981
  • The purpose of this dissertation is to study the physical properties of cellular rubber products for industrial use. Vulcanization characteristics were investigated by usingcure curve that had obtained by means of Rheometer. The results of physical properties, vulcanization characteristics and foaming states are as follows. 1. The test results for vulcanization characteristics of NR compounds indicated that in the recipe R-1. When accelerator D is used, the optimum conditions of vulcanizate are obtained, while formula R-2 and R-3 have shown higher torgue at curing time, $1{\sim}2$ minutes. Cellular rubber product test in terms of compression set and compression deflection has also met the requirements of SAE. 2. For SBR compounds, S-1 formula was the best in terns of vulcanization characteristics, and for the blowing structure of cellular rubber products, formula S-3 in which accelerator M is added was fair. All other test results, such as compression set and compression deflection properties met SAE requirements. 3. NBR compound (N-1) including accelerator TT was the best in terms of vulcanization characteristic and also blowing structure. All other properties listed above met requirements, particulary for oil resistance test. 4. In the test of EPDM compounds, when mixed accelerator, M and TT, is used(formula E-1) the best results were obtained. Since EPDM is hydrocarbon elastomer, oil resistance test failed. All other properties met the requirement specified in SAE.

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Experimental Evaluation of the Performance of Large-Capacity Mounts for Naval Shipboard Equipments (함정탑재장비용 대용량 마운트의 성능시험평가)

  • Moon, Seok-Jun;Kim, Heung-Sub;Park, Jin-Woo;Park, Jin-Ho;Oh, Kwang-Suk;Jeong, Jong-Ahn
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.3
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    • pp.275-281
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    • 2015
  • Mounts for shipboard equipment in naval ships play an important role for vibration and shock suppression. New large-capacity resilient mounts, SDR-D30 and SDR-D45, have been developed. This paper involves performance tests for the mount which have maximum load of 30 kN and 45 kN, respectively. The performance tests have been carried out for several mounts based on military standards, such as MIL-M-19863D(SH), MIL-M-21693C(SH), MIL-M-17508F(SH), and MIL-S-901D(NAVY). The test items consist of deflection at upper rate load test, dynamic stiffness, uniformity, static load-deflection(axial, transverse and longitudinal), drift test, fatigue test, and shock test. From these performance tests, it is confirmed that the two mounts have good performances based on military standards.

Measurement of Yield Strength for Electroplated Nickel Film Using Micro-cantilever

  • Moon, Hyoung-Sik;Kim, Jooh-Wan;Kim, Young-Min
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.5
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    • pp.247-251
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    • 2004
  • We report highly improved yield strength of nickel thin film, prepared using electroplating. The micro-scaled nickel cantilever is found to have significantly higher yield strength than bulk nickel. For the yield strength test, the heights of the micro-scaled cantilever were varied up to 60 ${\mu}{\textrm}{m}$ and electrostatic force was used for actuation. Stress of the bent cantilever was estimated using the FEM large deflection model. The yield strength of the thin nickel film is found to be over five times higher than that of the bulk nickel previously published. Results from this study indicate that metal microstructures can be used for MEMS applications requiring large deflection.

Evaluation of Comfort Limit on High Speed Railway Bridge Vibration Considering Passenger's Comfort (승차감을 고려한 고속철도 교량 진동사용성 평가)

  • Chin, Won-Jong;Kwark, Jong-Won;Choi, Eun-Suk;Kang, Jae-Yoon;Kim, Sung-Tae;Yoon, Hye-Jin;Kim, Nam-Sik
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.829-835
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    • 2011
  • This paper aims for proposed the deflection limit on vibration serviceability of high-speed railway bridges considering passenger's comfort when a train passes a railway bridge. The vertical acceleration signals of passenger cars obtained from test were compared with them from the bridge-train transfer function by riding KTX. The deflections by KTX of seven high speed railway bridges were assumed as sine and haversine wave. The deflection limit on vibration serviceability of high-speed railway bridges considering passenger's comfort when a train passes a railway bridge duration can be expanded using bridge-train transfer function and bridge comfort limit considering serviceability due to bridge vibration. And it was compared to other allowable deflection limits of railway bridge design specifications.

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