• 한국소음진동공학회논문집
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• 제23권3호
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• pp.218-225
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• 2013

Vertically-launched missiles are supported as erected vertically in the vertical launching system of warship, and they should be mounted in the same way when vibration-tested. However, mounting missiles vertically makes a fixture, which is a supporting structure, bulky and heavy so requiring a high-performance exciter. Mounting missiles as laid down horizontally in a vibration test is economical regarding fixture manufacturing and exciter performance, but it makes test results incorrect because the different mounting direction has effects on the test results. A bending moment due to missiles' weight happens to missiles, and resilient mounts, which support missiles in the vertical launch system, deflect differently from the real situation because of the static deflection of these mounts due to missiles' weight. If the resilient mounts supporting missiles have nonlinear force-deflection characteristics, vibration test results become more different from the true results. This paper proposes to support missiles with an additional resilient mount such as a bunge code in order to solve those problems coming from mounting vertically-launched missiles as laid down horizontally in vibration tests. The proposed approach enables to obtain the same test results as in their actual mounting condition even though vertically-launched missiles are mounted in a different direction.

• 임산에너지
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• 제18권2호
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• pp.84-91
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• 1999

The objective of this study was to present creep and the effects of mechano-sorptive deflection of drift pin moment resisting joint between LVL members under changing relative humidity (RH) conditions. The LVL members with steel gusset were jointed by a square pattern of eight injected drift pin. Three diameter drift pins were used to test specimens (6mm, 10mm, and 16mm). The creep test was conducted under two constant loading conditions : one at 30 kgf(840 kgf-cm) and the other at 60 kgf(1680 kgf-cm). The experiment was conducted in an open shed outside. (1)The total rotation creep model of moment resisting joing can be expressed as the sum of the creep of controlled environment (3-parameter model), dimensional change and mechano-sorptive deflection resulting from the variable environment. (2)Mechanosorptive rotation creep is recoverable as moisture content increases during adsorption. Least squares method for linear regression analysis was performed using mechano-sorptive rotation creep as the dependent variable and moisture content as the independent variable. The slope of low moment specimens are compared with those of high moment. This means that low moment condition is more easily affected by changes in humidity than high moment conditions. (3)Although creep deflection is higher for small diameter drift pin than for large diameter drift pin, the shape of creep deflection curves for all specimens is similar.

• 복합신소재구조학회 논문집
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• 제4권3호
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• pp.38-44
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• 2013

Glass fiber reinforced plastic (GRP) pipes buried underground are attractive for use in harsh environments, such as for the collection and transmission of liquids which are abrasive and/or corrosive. In this paper, we present the result of investigation pertaining to the structural behavior of GRP flexible pipes buried underground. In the investigation of structural behavior such as a ring deflection, experimental and analytical studies are conducted. In addition, vertical ring deflection is measured by the field test and finite element analysis (FEA) is also conducted to simulate behavior of GRP pipe buried underground. Based on the results from the finite element analyses considering soil-pipe interaction the vertical ring deflection behavior of buried GRP pipe is predicted. In addition, analytical and experimental results are compared and discussed.

• Restorative Dentistry and Endodontics
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• 제29권4호
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• pp.346-352
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• 2004

The purpose of present study was to evaluate the polymerization shrinkage stress and cuspal deflection in maxillary premolars resulting from polymerization shrinkage of composites and compomers. Composites and compomers which were used in this study were as follows: Dyract AP, Z100, Surefil. Pyramid, Synergy Compact, Heliomolar, Heliomolar HB, and Compoglass F. For measuring of polymerization shrinkage stress, Stress measuring machine (R&B, Daejon, Korea) was used. One-way ANOVA analysis with Duncan's multiple comparison test were used to determine significant differences between the materials. For measuring of cuspal deflection of tooth, MOD cavities were prepared in 10 extracted maxillary premolars. And reduction of intercuspal distance was measured by strain measuring machine (R&B, Daejon, Korea) One-way ANOVA analysis with Turkey test were used to determine significant differences between the materials. Polymerization shrinkage stress is $\mathbb{\ulcorner}$Heliomolar, Z100, Pyramid < Synergy Compact Compoglass F < Dyract AP < Heliomolr HB, surefil$\mathbb{\lrcorner}$ (P < 0.05). And cuspal delfelction is $\mathbb{\ulcorner}$Z100, Heliomolar, Heliomolar HB, Synergy Compact Surefil. < Compoglass F < Pyramid, Dyract AP$\mathbb{\lrcorner}$ (P < 0.05). Measurements of ploymerization shrinkage stress and those of cuspal deflection of the teeth was different. There is no correlation between polymerization shrinkage stress and cuspal deflection of the teeth(p > 0.05).

• 한국항공우주학회지
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• 제35권10호
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• pp.899-904
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• 2007

전투기급 항공기 개념설계 기간 중 항공기 초음속 순항성능에 미치는 앞전플랩 굽힘 효과를 분석하기 위하여 1/20 축척 날개-동체-꼬리 형상 모형을 사용한 고속 풍동시험을 수행하였다. 풍동시험을 위한 적절한 앞전플랩 각도를 선정하기 위하여 보정된 초음속 패널 방법을 사용하여 다양한 앞전플랩 굽힘 각도에 따른 공력특성을 분석하였다. 실험 및 수치해석적 접근 결과 분석을 기초로, 앞전플랩 굽힘 효과는 전투기급 항공기의 초음속 순항 성능 증대에 유용한 것으로 확인되었다.

• 대한토목학회논문집
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• 제9권4호
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• pp.41-49
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• 1989

전보(前報)에 이어서, 부분(部分) 프리스트레스트 콘크리트 부재(部材)의 실험결과(實驗結果)를 분석(分析)한다. 부분(部分) 프리스트레스트 콘크리트 부재(部材)는 사용하중하(使用荷重下)에서 균열의 발생을 허용(許容)하므로, 사용상태(使用狀態)의 처짐제한(制限)과 균열제한(制限)을 위하여 이들을 정확(正確)하게 예측(豫測)하는 것이 필요(必要)하다. 실험부재(實驗部材)의 하중(荷重)-처짐 관계(關係)에서 표리스트레스의 효과(效果)를 고찰(考察)하고, 각(各) 시방서(示方書)의 처짐식(式)과 실험결과(實驗結果)를 비교(比較)한다. 기왕(旣往)에 제안(提案)된 균열간격 및 균열폭 공식들과 실험부재(實驗部材)에서의 측정결과(測定結果)를 비교(比較)한다.

• 한국안전학회지
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• 제38권3호
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• pp.61-68
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• 2023

This study performed a structural performance evaluation of a system scaffolding for elevator installation work developed in previous studies. The structural performance was evaluated via a structural test conducted to apply the working load specified in the design standard. The deflection of the horizontal member and the stress of each member constituting the system scaffolding were measured. Consequently, the structural safety evaluation including structural behavior and required performance was performed using the deflection and stresses measured from the structural test. The structural test and safety evaluation results based on the heavy working load corresponding to the design load indicated that the deflection, which is the performance criterion of the horizontal member, did not exceed the allowable value. Further, each member's stress, which is a safety evaluation indicator, did not exceed the allowable strength for both horizontal and vertical members with bending behavior and fordable bracing with tensile behavior, while also satisfying the required safety factor. In addition, the results confirmed the safety against deformation, partial damage, and destruction owing to excessive and maximum load. Therefore, the system scaffolding developed in this study satisfies both the structural performance and safety required by the design standards; thus, it can be applied to elevator installation work sites.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1889-1894
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• 2012

바톰애쉬와 현장발생토사를 혼합한 유동성뒤채움재를 이용하여 실내모형실험을 수행하였다. 실내모형실험은 현장조건을 최대한 유사하게 모사하여 시공단계를 고려하여 실시하였다. 모형실험결과 뒤채움재 타설과정시 발생하는 최대수직변위는 4.43mm~6.6mm, 최대수평변위는 5.49mm~15.9mm로 나타났다. 하중재하시 최대 수직 변위는 2.41mm~8.69mm이고 최대 수평 변위는 3.02mm~4.25mm로 측정되었다. 하중을 제거한 후의 잔류변형은 수직방향 1.40mm~5.93mm, 수평방향 1.66mm~2.53mm로 나타났다. 동일한 크기의 하중재하시 일반모래뒤채움에 비해 유동성 뒤채움재의 수직 및 수평변위가 작게 나타났다. 유동성뒤채움의 경우 수평토압 경감효과가 크게 나타났다. 또한, 지표침하량의 경우 모래에 비해 유동성 뒤채움재에서 크게 경감되는 것으로 나타났다.

• 한국의류학회지
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• 제29권6호
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• pp.837-846
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• 2005

The purpose of this study is to suggest a standard of guidance for testing the performance and safety of motorcycle jacket with built-in airbag. The method of testing were as follows: The effects of the motorcycle jacket with built-in airbag are experimentaly investigated according to neck injury of FMVSS 208. The experiment consists of the crash simulation test by shield and the impact test. The head and neck injuries are evaluated based on industrial standards. Also, the displacements of the head and neck and chest are observed by film analysis. Using the results of the crash simulation test, neck injury$(N_ij)$ is discussed and the peak chest deflection of the results of the impact test, chest injury is pursued. Neck injury$(N_ij)$ of the result of the crash test show that the chance of a serious wound is $18\%$ if rider wear the R&D motorcycle jacket with built-in airbag(Type A). Chest injury is expected by peak chest deflection of the result of the impact test. The result of the peak chest deflection show that the reduction effect in chest injury of Type A motorcycle jacket is $10.3\%$.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.149-154
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• 2001

This paper presents the experimental study of the static stiffness for the BT Shank(7/24 Long Taper) and the HSK Tool Shank(1/10 Short taper). The static stiffness test was performed under different experimental conditions. The results obtained are as follows ; As known in the analysis results of the Load-Deflection diagram of the 7/24 Test tool shank, it is turned out that the diagram is a linear characteristics without regard to axial drawing force and according as the axial drawing force get to the 6kN, the static stiffness of the shank increase linearly. Thus the effective axial drawing force which maintains the static stiffness of the Main spindle taper of Machine Tool is larger than 6kN. It is found that the Load-Deflection diagram with 6kN of drawing force in the 1/10 Test tool shank is characterized by non-linear. But according as the axial drawing force is increasing by the 8kN, the diagram is characterized by linear. And increasing amount of deflection is about 60%. Therefore commendable axial drawing force is larger than 8kN. As a result, considering that the actual drawing force of the Machining Center is about 1300kgf and axial drawing force 12kN is equivalent amount as a 1220kgf, it is turned out that 1/10 Test tool shank superior to 7/24 Test tool shank in the static stiffness.