• 한국지진공학회논문집
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• 제6권2호
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• pp.21-28
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• 2002

Ductile behavior and strength of concrete-filled steel(CFS) piers was supported by many quasi-static cyclic loading tests. This test method, however, only estimates the member′s deformation capacity under escalating and repetitive displacement and ignores dynamic and random aspects of an earthquake load. Therefore, to understand complete seismic behavior of the structure against an earthquake, dynamic tests such as shaking table test and pseudo-dynamic tests are required as well as quasi-static tests. In this paper, following "Seismic Performance of Concrete-Filled Steel Piers Part I : Quasi-Static Cyclic Loadint Test", the seismic behavior of CFS and steel piers designed for I-Soo overpass in Seoul in investigated by the pseudo-dynamic test. In addition, the residual strength of both piers after an earthquake is estimated by the quasi-static test. The results show that both piers have satisfactory ductility and strength against well-known EI Centro earthquake although the CFS pier has better strength and energy dissipation than the steel pier.

• Wind and Structures
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• 제15권5호
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• pp.385-407
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• 2012

Bridge hanger vibrations have been reported under icy conditions. In this paper, the results from a series of static and dynamic wind tunnel tests on a circular cylinder representing a bridge hanger with simulated thin ice accretions are presented. The experiments focus on ice accretions produced for wind perpendicular to the cylinder at velocities below 30 m/s and for temperatures between $-5^{\circ}C$ and $-1^{\circ}C$. Aerodynamic drag, lift and moment coefficients are obtained from the static tests, whilst mean and fluctuating responses are obtained from the dynamic tests. The influence of varying surface roughness is also examined. The static force coefficients are used to predict parameter regions where aerodynamic instability of the iced bridge hanger might be expected to occur, through use of an adapted theoretical 3-DOF quasi-steady galloping instability model, which accounts for sectional axial rotation. A comparison between the 3-DOF model and the instabilities found through two degree-of-freedom (2-DOF) dynamic tests is presented. It is shown that, although there is good agreement between the instabilities found through use of the quasi-steady theory and the dynamic tests, discrepancies exist-indicating the possible inability of quasi-steady theory to fully predict these vibrational instabilities.

• 한국지반환경공학회 논문집
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• 제10권3호
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• pp.5-12
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• 2009

본 연구는 발전소의 적치장에서 채취한 석탄회의 정적 및 동적 강도를 제시하였다. 석탄회는 주로 저회로 이루어져 있으며 정적 및 동적 강도를 평가하기 위하여 NGI형 단순전단시험, 반복단순전단시험 및 직접전단시험을 수행하였으며, 이러한 시험으로부터의 강도를 모래의 강도와 비교하였다. 본 연구에 사용된 석탄회 속에 있는 저회는 입도분포에 의하면 모래로 분류되었으며 모래보다 높은 강도 특성을 보였다. 석탄회를 토목공사에 활용되기 위해서 사질토와 석탄회를 50:50의 비율로 배치플랜트에서 섞어 사용하는 것은 사질토층과 석탄회층을 교대로 층별 시공하는 것보다 비효율적이다. 혼합시공과 층별시공을 모사하기 위하여 모래와 석탄회가 50:50으로 조성된 시료를 준비하였다. 시험결과 혼합에 의한 시료가 층별시료보다 약간 큰 정적 및 동적 강도를 나타내었다. 높은 강도는 주로 저회의 모난 입자로부터 기인된 것으로 보인다. 혼합시료에서 액상화시의 반복응력비는 반복횟수가 증가함에 따라 층별시료보다 급격히 감소하였다.

• 한국안전학회지
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• 제15권4호
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• pp.20-27
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• 2000

The hat shaped section members, spot welded strength resisting structures are the most energy absorbing ones of automobile components during the front-end collision. Under the static axial collapse load in velocity of 10mm/min and quasi-static collapse load in velocity of 1000mm/min, the collapse characteristics of the hat shaped section and double hat shaped section member have been analyzed by axial collapse tests with respect to the variations of spot weld pitches on the flanges. In addition, the quasi-static collapse simulations have been implemented in the same condition to the experiment's using FEM package, LS-DYNA3D. The simulated results have been verified in comparison with these from the quasi-static axial collapse tests. With the computational approaches the optimal energy absorbing structures can be suggested. Simulations are so helpful that the optimized data be supplied in designing vehicles in advance.

• 한국군사과학기술학회지
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• 제26권4호
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• pp.344-351
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• 2023

Static ejection tests were conducted using the 2,000lb-Class Store to provide ejector model for the store separation simulation. In this study, static ejection test device for 2,000lb-class store was constructed and reaction force applied to store was measured over time. In addition, the trajectories of the ejected store were obtained using photogrammetry and compared with the simulations using developed ejector model. The results of the static ejection test were analyzed to determine the cartridge-orifice combination to be used for store separation. Flight tests were performed by applying the analysis results and verified that the store was safely separated from the aircraft.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.166-173
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• 2013

An aluminum suspension corner module is widely used in high class passenger cars to reduce vehicle weight and improve fuel economy. According to the change of material and suspension type, the evaluation of the static strength and failure mode of the corner module is important. In this study, static strength and failure mode analysis of aluminium multi-link suspension corner module is presented. Static strength test system is designed and static failure mode tests of the corner module are carried out in longitudinal, lateral, and vertical direction. From the resuls of the tests we found that the failure modes are different compare to those of the steel corner module. The static failure modes and load-displacement curves of this study will be used as a guidance in design of a passenger car aluminium multi-link suspension corner module.

• 한국지반공학회논문집
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• 제20권6호
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• pp.137-150
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• 2004

모래의 aging 현상은 점성토에 비하여 무시할 정도로 매우 작아서 최근까지 연구되지 않았다. 그러나 퇴적이나 교란 후 시간경과에 따라 관입저항치의 증가가 관찰되면서 현장시험을 중심으로 모래의 aging 효과에 대하여 활발한 조사가 이루어졌고, 최근에는 현장시험뿐만 아니라 실내시험에서도 여러 연구자들에 의해 모래의 aging 효과가 규명 되어지고 있다. 본 연구에서는 모래의 비배수 정적전단거동에 대한 aging 효과를 살펴보기 위해 낙동강 모래를 이용하여 상대밀도 $(D_r)$, 압밀응력비$(K_c)$ 그리고 압밀시간을 달리하여 비배수 정적삼축압축시험을 실시하였다. 그 결과 응력-변형률의 탄성구간내 탄성계수가 압밀시간 경과에 따라 증가하는 것으로 나타났으며, 또한 상전이점 강도$(S_{PT})$와 한계응력비점 강도$(S_{CSR})$도 압밀시간 경과에 따라 증가하였다. 그러나 간극수압비$(u/{p_c}')$는 압밀시간에 비례하게 감소하는 등 모래의 정적전단에서 나타나는 aging 효과를 관찰할 수 있었다.

• Steel and Composite Structures
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• 제21권2호
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• pp.323-342
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• 2016

To study the effect of collar-plate reinforcement on the static strength of tubular T-joints under axial loading, fundamental research work is carried out from both experimental test and finite element (FE) simulation. Through experimental tests on 7 collar-plate reinforced and 7 corresponding un-reinforced tubular T-joints under axial loading, the reinforcing efficiency is investigated. Thereafter, the static strengths of the above 14 models are analyzed by using FE method, and it is found that the numerical results agree reasonably well with the experimental data to prove the accuracy of the presented FE model. Additionally, a parametric study is conducted to analyze the effect of some geometrical parameters, i.e., the brace-to-chord diameter ratio ${\beta}$, the chord diameter-to-chord wall thickness ratio $2{\gamma}$, collar-plate thickness to chord wall thickness ratio ${\tau}_c$, and collar-plate length to brace diameter ratio $l_c/d_1$, on the static strength of a tubular T-joint. The parametric study shows that the static strength can be greatly improved by increasing the collar-plate thickness to chord wall thickness ratio ${\tau}_c$ and the collar-plate length to brace diameter ratio $l_c/d_1$. Based on the numerical results, parametric equations are obtained from curving fitting technique to estimate the static strength of a tubular T-joint with collar-plate reinforcement under axial loading, and the accuracy of these equations is also evaluated from error analysis.

• Steel and Composite Structures
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• 제24권5호
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• pp.615-633
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• 2017

Fatigue crack initiated in welded tubular joints due to cyclic loading may produce harmful effect on the integrity of the tubular structures. To study such effect, both fatigue and static tests on nine circular tubular T-joint specimens made of carbon steel materials were carried out. The specimens were subjected to tensile loading in both fatigue and static tests. The load-displacement relation, the crack propagation and the failure mode of the specimens are all analyzed. The deterioration of the static strength of the cracked T-joints is also investigated and evaluated through an area reduction factor. Experimental results indicate that the static strength of a tubular T-joint with a surface crack seems to decrease slightly while a through crack has relatively remarkable effect on the reduction of the static strength. Additionally, experimental results also show that the toughness of the materials and the geometry of the specimens play an important role on the failure process of cracked tubular T-joints.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.375-382
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• 2003

This study, Using Pusan clay, examined a relationship between Dynamic and Static Liquid Tests. The Static Liquid Tests wow carried out based on BS and JIS. The results of the study are summarized as follows. (1) The result of the Dynamic Liquid Limit Test showed that the liquid limit values of air-dried soil were greater than those of oven-dried soil by 4%~15% (2) The liquid limit value of the Static Liquid Limit Test was greater than that of the Dynamic Liquid Limit Test by 2%~9%. The following equations show the relationship between the two values WL,Fall(JIS) = 0.961ㆍWL,Cas. + 4.209 WL,Fall(BS) = 0.969ㆍWL,Cas + 5.024 (3) The liquid limit value of BS was greater than that of JIS by 1%~6%. The following equation shows the relationship between the two values.