• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.2 s.21
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• pp.9-15
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• 2006

Structures of Civil Engineering have been designed with a safety as their main purpose. However recently, the greenness side of the technology of civil engineering regarded as most Important and also utility values and stability of the structures. Also developments in the technology make materials to be higher strength and they shortened scales and stiffness of the structural members. This means that it brings an immoderate deflection and vibration of bridge structures simultaneously. Accordingly, this study ai ed to find and estimate the most idealized structure models on the effects of the deflection and vibration of bridges from the traffic lane load and human vibration - the main pass of bridge structures.

• Journal of Digital Contents Society
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• v.19 no.4
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• pp.615-620
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• 2018

Evaluation of clinical usefulness of current perception threshold test and vibration sense perception threshold test in diagnosing the diabetic poly-neuropathy patients is one of the diagnosis methods for diabetic poly-neuropathy. Up to the present, some diagnostic methods were used for diabetic poly neuropathy patients. For example, there are neuropathy impairment score test of lower limbs, nerve conduction test, cooling detection threshold test, heat-pain threshold test and so on. However, most of the above tests require very expensive cost and take a lot of time in test. In this paper, a new apparatus estimating vibration sense ability is introduced. For this purpose, the VCM(voice coil motor) stimulating patient's peripheral nerve and current amplifier were manufactured. Also, softwares sensing and driving the vibration detection threshold test in order to measure the quantitative vibration sensory levels in diabetic poly-neuropathy patients were developed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.781-786
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• 2009

The thesis shows that we gauged vibration of vehicular load regarding WPC girder bridge and researched into dynamic characteristics(natural frequency, vibration acceleration) of WPC girder bridge. By the basic of that, we researched on vibration serviceability by looking over and being compared to vibration criteria we had before. In the thesis, the gauged vibration made an analysis of vertical acceleration through FFT method and evaluated vibration serviceability about vibration sense the body feels by means of the standard of ISO assessment standard and Meister assessment standard by referring to analysis data. This research on bridge is WPC girder bridge of 90m span, width of 5.5m, and the experiment was gauged by a fluent which is right way and inverse way about dump truck of gross 270kN. Acceleration was located in the middle of 1st span, 2nd span, 3rd span. As a result of appraisal standard of Meister, the vibrations of the bridge have distributed between "Level C, Strongly Perceptible" and "Level B, Disturbing". Also the vibration can be attacked with unpleasant feeling. As a result of appraisal standard of ISO, from vibration influence didn't come to 60s, and reduced comfort boundary in part of most rigorous standard that such a case didn't happen.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.4
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• pp.331-337
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• 2010

The thesis shows that we gauged vibration of vehicular load regarding WPC girder bridge and researched into dynamic characteristics(natural frequency, vibration acceleration) of WPC girder bridge. By the basic of that, we researched on vibration serviceability by looking over and being compared to vibration criteria we had before. In the thesis, the gauged vibration made an analysis of vertical acceleration through FFT method and evaluated vibration serviceability about vibration sense the body feels by means of the standard of ISO assessment standard and Meister assessment standard by referring to analysis data. This research on bridge is WPC girder bridge of 90 m span, width of 5.5 m, and the experiment was gauged by a fluent which is right way and inverse way about dump truck of gross 270 kN. Acceleration was located in the middle of 1st span, 2nd span, 3rd span. As a result of appraisal standard of Meister, the vibrations of the bridge have distributed between "level C, strongly perceptible" and "level B, disturbing". Also the vibration can be attacked with unpleasant feeling. As a result of appraisal standard of ISO, from vibration influence didn't come to 60s, and reduced comfort boundary in part of most rigorous standard that such a case didn't happen.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.129-140
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• 2000

최근들어 핵폐기물 지하처분장을 중심으로 터널굴착에 의한 주변 암반의 손상상태와 암반특성의 변화를 정량적으로 평가하기 위한 시도가 이루어지고 있다. 이는 암반의 지지력을 적극적으로 이용하는 NATM개념에 의해 터널을 시공할 셩우 안정성 해석과 최적 보강설계를 위해 필수적인 사항으로 고려된다. 그러나 현재까지 암반 손상영역을 평가하기 위해 제시된 여러 방법들은 아직까지 그 적용성과 타당성이 충분히 검증되지 못한 실정이다. 이 연구에서는 코어시추, 실험실시험, 발파진동측정, 보어홀 카메라 등의 여러 방법에 의해 손상영역을 정량적으로 평가하고자 하였으며 가 방법의 적용성을 검토하였다. 암반상태 및 발파조건을 달리하여 시험발파를 수행하였으며 발파 후에 터널벽면에 수직하게 시추를 하여 암석코어를 채취한 뒤 손상정도에 따른 암석의 물리적, 역학적 특성들？ 변화를 정량적으로 나타내고자 하였다. 코어 채취후 시축공에 보어홀 카메라를 사용하여 손상영역을 시각적으로 판별하고자 하였으며 발파진동 측정결과로부터 손상영역을 예측하고 채취한 암석시표에 대한 실험실시험 결과와 비교하여 적용성을 검토하였다.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.166-166
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• 2011

한국건설기술연구원내에 세계 최초로 UHPC(초고성능 콘크리트)를 활용한 보도사장교를 설계 및 시공하여 공용중이다. 초고성능 콘크리트(UHPC, Ultra High Performance Concrete)는 기존의 콘크리트의 단점을 극복하기 위하여 강섬유 및 혼화재료를 사용하여 고강도화와 더불어 인장강도, 휨강도, 균열에 대한 저항성, 전단강도 및 내충격성을 대폭 개선시켜서 구조부재의 연성 및 강도를 확보하기 위해 개발된 것으로서 한국건설기술연구원이 독자적 연구를 바탕으로 UHPC를 개발하였고, KICT-UHPC의 특성을 충분히 반영한 보도사장교를 한국건설기술원내에 실구조물로 시공하였다. 한국건설기술연구원내 본관 1, 2동 연결 보도사장교(SUPER BRIDGE 1)의 진동실험을 통해 UHPC 보도사장교의 동특성(고유진동수 및 모드형상)을 평가하였다. 대상교량에는 보도사장교의 캔틸레버 구조 특성에 의해 발생하는 진동을 제어하기 위한 질량 264kg의 난간형 수직진동제어장치(TMD) 4대가 설치되어 있으며, 부가질량의 운동을 기계적으로 구속하거나 구속을 해제하여 TMD의 작동을 켜거나 끌 수 있도록 되어있다. TMD의 가동 및 정지시 동특성을 비교하는 정밀한 검증 실험을 통하여 TMD 설치에 의한 동특성의 변화도 평가하였다. 가진망치에 의한 충격실험으로부터 획득한 가속도 시간이력 데이터와 가진망치의 가진력 시간이력 데이터를 사용하여 주파수응답함수(FRF, frequency response function)를 계산하고, 이로부터 Super Bridge I의 동적모드형상과 고유진동수를 추출하였다. 1차 모드의 고유진동수는 TMD 정지시 2.2949 Hz, TMD 작동시 2.0996 Hz로서 8%정도 감소하였다. 충격해머에 의한 가진 실험을 통해 세계 최초로 시공한 UHPC 보도사장교의 진동특성과 관련한 신뢰성 있는 자료를 확보할 수 있었다.

• Journal of the Korea Society of Computer and Information
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• v.16 no.5
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• pp.61-71
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• 2011

To measure the fatigue of metallic objects at high speed vibration while non-contact precision displacement measurement on how to have a lot of research conducted. Noncontact high-speed vibration detection sensor of the eddy current sensors and laser sensors are used, but it is very expensive. Recently, High-speed vibrations detection using an inexpensive inductive sensor to have been studied, but is still a beginner. In this paper, a new design of an inexpensive inductive proximity sensor has been suggested in order to measure high frequency dynamic displacements of metallic specimens in a noncontact manner. Detection of the existing inductive sensors, detection, integral, and amplified through a process to detect the displacement noise due to weak nature of analog circuits and integral factor in the process of displacement detection is slow. The proposed method could be less affected by noise, the analog receive and high-speed signal processing is a new way, because AD converter (Analog to Digital converter) without using the vibration frequency signals directly into digital signals are converted. In order to evaluate the sensing performance, The proposed sensor module using non-contact vibration signals were detected while shaker vibration frequencies from 30Hz to 1,100 Hz at intervals of vibrating metallic specimens. Experimental results, Vibration frequency detection range of the metallic specimins within close proximity to contactless 5mm could be measured from DC to 1,100Hz and vibration amplitude of the resolution was $20{\mu}m$. Therefore, the proposed non-contact inductive sensor module for precision vibration detection sensor is estimated to have sufficient performance.

• The tire
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• s.122
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• pp.32-38
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• 1986

타이어는 승용차를 비롯한 각종차량이나 항공기 등의 중요부품으로서 실로 광범위한 기능을 다하고 있는 것이다. 타이어는 무엇보다도 안전주행을 할 수 있어야 하고 자동차를 사용하는데 있어서의 경제성도 고려되어야 한다. 그리고 특히 승용차인 경우에는 차의 조종ㆍ안정성이나 진동ㆍ승차감ㆍ소음 등의 각종 요구에도 만족되어야 한다. 따라서 타이어가 이와같은 각종 요구조건을 만족시키고 있는가를 알기 위해서는 여러가지 시험을 통해서 평가하지 않으면 안된다. 또한 당연한 일이겠지만 이와같은 결과는 타이어 개발에 많이 활용되어야만 될 것이다. 타이어의 역할은 차량에 낀 다음부터 나타나게 되므로 타이어의 최종적인 평가는 실차시험에 따르는 것이 가장 좋으나, 시험의 능률, 경제성, 정밀도, 재현성 등의 여러가지 문제가 있기 때문에 실내시험으로 대체할 수 있는 제특성에 대해서는 가능한 한 여러가지의 실내시험기로 측정하는 방법을 택하고 있다. 그러나 자동차와의 조화로 나타나는 조종안정성이나 진동ㆍ소음: 승차감 등에 대해서는 실차시험으로 최종적인 평가ㆍ판정을 하는 수 밖에 없으므로 현재 세계의 많은 타이어 메이커들은 타이어 테스트코스를 설치하여 많은 시험차를 가지고 시험하고 있다. 따라서 여기서는 타이어의 시험이 어떠한 방법으로 이루어지고 있는지를 살펴보고자 한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.104-111
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• 2016

The steel frame modular housing of which the research and development has been actively carried out recently cannot be constructed through monolithic placement like the reinforced concrete deck of general structure due to the characteristics of construction method of production in the factory and assembly on the site. And floor vertical vibration and deflection caused by inhabitants' activities may become an important issue in the aspect of usability evaluation due to a decrease in the section size of member, a decrease in weight, and so on. Therefore, this study evaluated the vibration performance of deck by using formula of AISC Design Guide 11(hereinafter AISC formula) which was practically used in general for modules where a stud was and wasn't installed at the center of beam in the longitudinal direction in the modular housing to be studied, and examined the applicability of AISC formula through comparison with the results of analysis using a general-purpose analysis program. On the basis of this, a structural cause for an error to occur between analysis result and AISC formula in the deck of module in which a stud was installed was analysed, and measures for considering this were suggested. Besides, an analysis model with the variables of measures for improving the floor vibration performance of modular housing to be studied was established. And measures having excellent vibration performance and economic feasibility were suggested through vibration response analysis and economic evaluation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.4
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• pp.245-253
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• 2020

In this study, natural frequencies are compared using several pile-soil interaction (PSI) models to evaluate the effects of each model on resonance safety checks for a monopile type of wind turbine structure. Base spring, distributed spring, and three-dimensional brick-shell models represented the PSIs in the finite element model. To analyze the effects of the PSI models on a natural frequency, after a stiffness matrix calculation and Winkler-based beam model for base spring and distributed spring models were presented, respectively; natural frequencies from these models were investigated for monopiles with different geometries and soil properties. These results were compared with those from the brick-shell model. The results show that differences in the first natural frequency of the monopiles from each model are small when the small diameter of monopile penetrates hard soil and rock, while the distributed spring model can over-estimate the natural frequency for large monopiles installed in weak soil. Thus, an appropriate PSI model for natural frequency analyses should be adopted by considering soil conditions and structure scale.