• Structural Engineering and Mechanics
• /
• 제11권6호
• /
• pp.651-662
• /
• 2001

In order to investigate the seismic behavior and seismic design methods in the transverse direction of a shield tunnel, a series of model shaking table tests and a two-dimensional finite element dynamic analysis on the tests are carried out. Two kinds of static analytical methods based on ground-tunnel composite finite element model and beam-spring element model are proposed, and the validity of the static analyses is verified by model shaking table tests. The investigation concerns the dynamic response behavior of a tunnel and the ground, the interaction between the tunnel and ground, and an evaluation of different seismic design methods. Results of the investigation indicate that the shield tunnel follows the surrounding ground in displacement and dynamic characteristics in the transverse direction; also, the static analytical methods proposed by the authors can be used directly as the seismic design methods in the transverse direction of a shield tunnel.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2003년도 학술발표논문집
• /
• pp.207-210
• /
• 2003

This study, using Pyongteak & Tangjin soil, examined a relationship between Dynamic and Static Liquid Limit Tests. The Liquid Limit Tests were carried out based on BS and KS. The results of the study are summarized as follows. The liquid limit value of the Static Liquid Limit Test was greater than that of the Dynamic Liquid Limit Test be 4% - 14%. The following equation shows the relationship between the two values.(Coefficient of Correlation = 0.88) $$BS(LL)=0.7519{\times}KS(LL)+19.174$$

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.299-302
• /
• 2005

This study deals with the quasi-static tests on steel reinforced concrete composite columns with single embedded steel or multiple members. For the design of bridge piers, the composite section needs to have low steel ratio for cost savings because the dimension of the pier section is usually large. There is lack of design guidelines for these composite columns with low steel ratio, but the design provisions for the normal reinforced concrete column can be used for the design because of the low steel ratio. It is necessary to provide the design provisions in terms of the strength limit state and seismic performance by the detail requirements on the longitudinal steel and the transverse steel. The test parameters in this study were determined considering the current design provisions on RC columns. Through the quasi-static tests, the seismic performance of the composite columns were discussed.

• 한국정밀공학회지
• /
• 제18권11호
• /
• pp.34-41
• /
• 2001

This study is to investigate the energy absorption characteristics of CFRP(Carbon-Fiber Reinforced Plastics) tubes on static and dynamic tests. Axial static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine) and dynamic compression tests have been utilized using an vertical crushing testing machine. When such tubes are subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that could control the crushing process. The collapse characteristics and energy absorption have been examined for various tubes. Energy absorption of the tubes are increased as changes in the lay-up which may increase the modulus of tubes. The results have been varied significantly as a function of ply orientation and interlaminar number.

• 한국자동차공학회논문집
• /
• 제9권6호
• /
• pp.195-200
• /
• 2001

Composites have wide applications in aerospace vehicles and automobiles because of the inherent flexibility in their design for improved material properties. Composite tribes in particular, are potential candidates for their use as energy absorbing elements in crashworthiness applications due to their high specific energy absorbing capacity and the stroke efficiency. Their failure mechanism however is highly complicated and rather difficult to analyze. This includes fracture in fibres, in the matrix and in the fibre-matrix interface in tension, compression and shear. The purpose of this study is to investigate the energy absorption characteristics of CFRP(Carbon Fiber Reinforced Plastics) tubes on static and impact tests. Static compression tests have been carried out using the static testing machine and impact tests have been carried out using the vertical crushing testing machine. Interlaminar number affect the energy absorption capability of CFRP tubes. Also, theoretical and experimental have the same value.

• 항공우주기술
• /
• 제3권1호
• /
• pp.27-34
• /
• 2004

50m 무인 비행선 비아50의 주 구조물인 꼬리날개, 곤돌라, 추력모터마운트(EMS) 등은 탄소 및 유리 섬유 복합재를 이용하여 설계/제작되었다. 사용된 재료 시편 강도 시험을 수행하여 설계 물성치를 확정하였다. 각각의 구조물들에 대하여 정하중 시험을 수행하여 구조 건전성을 입증하였다. 각 단품별로 정하중 시험을 수행하였으며, 보다 정확한 시험을 위하여 조립상태를 고려한 경계조건을 모사하였다. 100% DLL에서 영구변형이 발생하지 않음을 보였고, 150% DLL에서 파손이 발생하지 않음을 입증하였다.

• 대한안전경영과학회지
• /
• 제3권1호
• /
• pp.127-137
• /
• 2001

Because of the inherent flexibility in their design for improved material properties, composites have wide applications in aerospace vehicles and automobiles. The purpose of this study is to investigate the energy absorption characteristics of CFRf (Carbon Fiber Reinforced Plastics) tubes on static and impact tests. Static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine) and impact compression tests have been carried out using the vertical crushing testing machine. When such tubes were subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that control the crushing process. The collapse characteristics and energy absorption were examined. Trigger and interlaminar number affect the energy absorption capability of CFRP tubes.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.356-363
• /
• 2004

In this research, the shear behavior of four different interfaces consisting of 4 types of geosynthetics was examined, and both static and dynamic tests for the geosynthetic interface were conducted. The monotonic shear experiments were performed by using an inclined board apparatus and large direct shear device. The interface shear strength obtained from the inclined board tests were compared with those calculated from large direct shear tests. The comparison results indicated that direct shear tests are likely to overestimate the shear strength in low normal stress range where direct shear tests were not performed. Curved failure envelopes were also obtained for interface cases where two static shear tests were conducted. By comparing the friction angles measured from three tests, i.e. direct shear, inclined board, and shaking table tests, it was found that the friction angle might be different depending on the test method and normal stresses applied in this research. Therefore, it was concluded that the testing method should be determined carefully by considering the type of loads and the normal stress expected in the field.

• Geomechanics and Engineering
• /
• 제37권1호
• /
• pp.85-95
• /
• 2024

This study investigates the influence of nano-silica and basalt fiber content, curing duration, and freeze-thaw cycles on the static and dynamic properties of soil specimens. A comprehensive series of tests, including Unconfined Compressive Strength (UCS), static triaxial, and dynamic triaxial tests, were conducted. Additionally, scanning electron microscopy (SEM) analysis was employed to examine the microstructure of treated specimens. Results indicate that a combination of 1% fiber and 10% nano-silica yields optimal soil enhancement. The failure patterns of specimens varied significantly depending on the type of additive. Static triaxial tests revealed a notable reduction in the brittleness index (IB) with the inclusion of basalt fibers. Specimens containing 10% nano-silica and 1% fiber exhibited superior shear strength parameters and UCS. The highest cohesion and friction angle were obtained for treated specimens with 10% nano-silica and 1% fiber, 90 kPa and 37.8°, respectively. Furthermore, an increase in curing time led to a significant increase in UCS values for specimens containing nano-silica. Additionally, the addition of fiber resulted in a decrease in IB, while the addition of nano-silica led to an increase in IB. Increasing nano-silica content in stabilized specimens enhanced shear modulus while decreasing the damping ratio. Freeze-thaw cycles were found to decrease the cohesion of treated specimens based on the results of static triaxial tests. Specimens treated with 10% nano-silica and 1% fiber experienced a reduction in shear modulus and an increase in the damping ratio under freeze-thaw conditions. SEM analysis reveals dense microstructure in nano-silica stabilized specimens, enhanced adhesion of soil particles and fibers, and increased roughness on fiber surfaces.

• Elastomers and Composites
• /
• 제52권4호
• /
• pp.303-308
• /
• 2017

In this study, finite element modeling and material property tests are performed for the finite element analysis of rubber isolator parts which support the engine and isolate the vibration. As a result of the P direction analysis of the rubber isolator parts, the static stiffness in the P direction was 44.2 kg/mm, which is well within the error of 5% as compared with the test result of 46.1 kg/mm. The static stiffness of the rubber isolator parts in the Q direction was calculated to be 7.9 kg/mm, which is comparable to the test result of 8.6 kg/mm, with an error of less than 8%. As a result of the analysis on the Z direction, the static stiffness was calculated as 57.7 kg/mm, and the test results were not available. Through this study, it is expected that the time and cost for prototype development can be reduced through nonlinear finite element analysis for rubber isolator parts.