• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.95-100
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• 1999

Dynamic measurements are used rather sparingly to determine the elastic modull of rock cores and modulus values are not much utilized in design practice. The reason seems to result from the general perception that values obtained by dynamic measurement are much higher (about 10 times) than those determined statically. This paper presents results from dynamic and static tests on rock cores. The findings are: 1) elastic modull can be consistently determined by laboratory seismic testing. 2) nonlinear deformation characteristics of rock cores was tentatively proposed with variation in elastic modulus with strain.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.567-569
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• 2011

플러그인 프레임워크는 구성요소 간 높은 종속관계 및 낮은 유연성을 해결하고자 개발된 S/W 기반요소로서, 프레임워크를 구성하는 컴포넌트를 플러그인으로 제공하여 구성요소의 추가 및 변경이 동적으로 이루어지게 한다. 이를 통해 소프트웨어 구성을 위해 필요한 컴포넌트들이 동적으로 추가 혹은 변경하여 소프트웨어를 구현 가능하게 되어 소프트웨어의 확장성 및 재사용성을 증대시킨다. 하지만, 플러그인 프레임워크 기반의 소프트웨어 개발 과정은 낮은 종속관계의 구성요소가 결합되어 이뤄지는 만큼, 개별 구성요소의 인터페이스 및 구성요소 간 통합을 사전에 검증할 수 있는 통합시험환경에 대한 필요성이 제기된다. 이에 본 논문은, 동적 구성요소의 개별 인터페이스 검증 및 구성요소 간 통합검증이 가능한 플러그인 프레임워크 기반에서의 통합시험도구에 대해 제안하고, 이에 대한 개략설계내용을 기술한다.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.47-54
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• 2005

In many practical cases, design methods of pile have been used mainly semi empirical bearing capacity equations. It can be done that confirmation of pile bearing capacities through using of dynamic and static tests during constructing or after constructions. If a prediction of layered point pile bearing capacity could be done through simple tests during field investigation, it could be done that more reliable design of pile than a prediction of using semi empirical equations or static formulations. This paper suggests a method to estimated point bearing capacity during in-situ investigation by using the dynamic rod model pile and verifies the point bearing capacity compare with results of static pile load tests. From test results, the unit ultimate point bearing capacities are relatively similar through a dynamic rod model pile tests and static pile load tests. The unit ultimate point bearing capacity by using N value is shown about 50 % value of measured unit ultimate point bearing capacity from field test result and the prediction of the unit ultimate point bearing capacity by using N value is shown very conservative, illogical and uneconomical pile designs.

• Tunnel and Underground Space
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• v.22 no.5
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• pp.339-345
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• 2012

Information on the deformation behavior and fracture strength of rocks subjected to dynamic loadings is important to stability analyses of underground openings underground vibration due to rock blasts, earthquakes and rock bursts. In this study, Split Hopkinson Pressure Bar (SHPB) system was applied to estimate dynamic compressive and tensile fracture strengths of limestone and also examine deformation behavior of limestones under dynamic loadings. A micro-focus X-ray CT scanner was used to observe non-destructively inside the impacted limestone specimens. From the dynamic tests, it was revealed that the limestone have over 140MPa dynamic compressive strength and the strain-rate dependency of the strength. Dynamic Brazilian tensile strength of the limestone exceeds 21MPa and shows over 3 times static Brazilian tensile strength.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.2
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• pp.80-85
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• 2005

This study, Using Pusan clay, examined a relationship between Dynamic and Static Liquid Tests. The Static Liquid Tests were 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 Natural condition 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 tile two values. WL, Fall(JIS)=0.961$\cdot$WL, Cas+4.209, WL, Fall(BS)=0.969$\cdot$WL, 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. WL, Fall(BS)=0.976WL, Fall(JIS)+2.638.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.4
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• pp.27-36
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• 2012

The simulation of the field dynamic soil properties for soil modeling in the centrifuge test is important. In this study, the process of soil modeling based on the shear wave velocity profile is developed. From the resonant column test in each confining pressure, the shear wave velocity profile is expected and the modeling condition is determined by comparing it with that in the field. During the dynamic centrifuge test, the bender element test is performed for measuring the in-flight shear wave velocity profile, and the applicability of the proposed method was verified. This modeling method is applied to the centrifuge test of the Hualien Large-Scale Seismic test.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.5 s.45
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• pp.21-28
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• 2005

This paper proposes a shaking table test considering the dynamic soil strcuture interaction (SSI) by using the accelerations measured from superstructure and shaking table. The proposed method based on the substructure method is that only superstructure is used as an experimental model and dynamic soil stiffness is reflected on the controller of shaking table for soil model. At the moment, an experimental superstructure is excited by a shaking table with the motion required to emulate the dynamic behavior of total SSI system. First, the validity of the proposed method is verified by the verification model of numerical simulation, which is derived from the equation of motion of SSI system under consideration. Also, the applicability of the proposed method to shaking table test is numerically verified from the simulation model incorporating the transfer function of shaking table.

• Composites Research
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• v.12 no.1
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• pp.68-75
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• 1999

This study has observed that the dynamic behavior of Metal Matrix Composites (MMCs) in low velocity impact varies with impact velocity. MMCs with 15 fiber volume percent were fabricated by using the squeeze casting method. The AC8A was used as the matrix, and the alumina and the carbon were used as reinforcements. The tensile and vibration tests conducted yielded the yielded the tensile stress and elastic modulus of MMCs The low pass filter and instrumented impact test machine was adopted to study dynamic behaviors of MMCs corresponding to impact velocity. Stable impact signals were obtained by using the low pass filter. Impact corresponding to impact velocity. Stable impact signals were obtained by using the low pass filter. Impact energy of unreinforced alloy and MM s increased as the impact velocity increased. The increase of crack propagation energy was especially prominent, but the dynamic toughness of each material did not change much. To show the relation between crack initiation energy and dynamic fracture toughness, a simple model was proposed by using the strain energy and stress distribution at notch. The model revealed that crack initiation energy is proportional to the square of dynamic fracture toughness and inversely proportional to elastic modulus.

• Journal of the Korean GEO-environmental Society
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• v.23 no.5
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• pp.25-32
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• 2022

As recently, there have been two earthquakes with a magnitude of 5.0 or greater in Korea and the number of smaller earthquakes has increased, a lot of research and interest in earthquake-resistant design are increasing. Especially, the Pohang earthquake has also raised interest in earthquake-resistant design of port facilities. In this study, experiments and analysis were conducted on the dynamic behavior of upright and inclined breakwaters during earthquakes among port structures through the 1g shaking table test. To this end, three seismic waves were applied to the model to which the similarity law (scale effect) was applied: long period (Hachinohe), short period (Ofunato) and artificial seismic waves. The acceleration and displacement of the upright and inclined breakwaters were analyzed according to whether the DCM method was reinforced during earthquakes based on the results of shaking table test. As the result, the dynamic behavior of the upright and inclined breakwater shows a tendency to suppress the amplification of acceleration as bearing capacity and rigidity increase when DCM method is reinforced.

• The Korean Journal of Rheology
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• v.9 no.3
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• pp.97-102
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• 1997

내피로성은 기계적 구조물로 사용되는 고분자재료에는 반드시 필요한 성질이며, 피 로거동은 재료특유의 비선형 동적 점탄특성과 아주 밀접한 관계가 있다. 본 연구에서는 피 로과정에서의 비선형 동적 점탄특성을 정량적, 연속적으로 측정할수 있는 시험 기기와 가해 준 변형에 대한 응답 응력파의 기본 응력파(선형적 응답)로부터의 차이를 직접 측정하여 이 를 규격화한 비선형 점탄성파라미터, NVP(Nonlinear Viscoelastic Parameter)라 명명한 새 로운 평가방법을 개발하였다. 그리고 고밀도 폴리에틸렌(HDPE) 배향물을 사용하여 그 평가 방법의 타당성을 조사한 결과 피로과정에서의 비선형동적 점탄특성을 나타내는 NVP가 증 가함에 따라 재료의 피로수명은 감소하였다. 따라서 NVP가 고분자재료의 내피로성을 평가 하는 척도로서 사용가능하다는 사실이 증명되었다. 또한 각 고조파 성분에대해 조사한 결과 인장형 피로시험양식에서는 고체입자 분산계의 전단변형에서 나타난 비선형 점탄성의 결과 와는 달리 2차 성분의 크기가 가장컸으며 NVP에의 기여도도 가장 크게 나타났다. 이는 변 형양식의 차이에 따른 결과를 볼수 있다.