• 한국안전학회지
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• 제19권4호
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• pp.69-73
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• 2004

The flash point is one of the most important combustible properties used to determine the potential for the fire and explosion hazards of industrial material and the fire point is the temperature of the flammable liquid at which there will be flaming combustion, sustained 5 seconds in response to the pilot flame. In this study, the flash point and fire point were measured to present raw data of the flammable risk assessment for alcohols, using Tag open-cup apparatus(ASTM D 1310-86). The measured values were compared with the calculated values based on 0.78 times stoichiometric concentration. The values calculated by the proposed equations were in good agreement with the measured values.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1041-1046
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• 2002

A railway open deck plate girder bridge without ballast should support relatively heavier vehicle loads compared with its self-weight. For such a reason, actual dynamic response of the bridge is considerably differing with normal prediction because additional masses added from vehicle to a bridge have an effect on the dynamic characteristics of the bridge. These differences affect to the estimation of a natural frequency change that adopted for one of the evaluation technique of strength decrease, and these make trouble to the analysis of a natural frequency from the field test data that measured at the bridge subjected to a running vehicle. In this study, classification of mass participation ratio for each component of open deck plate girder bridge without ballast and the comparison according to the change of vibration characteristics for the case of subjected to a running vehicle were accomplished.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.161-164
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• 2000

In this paper, a finite element structural analysis for thin-walled open-section composite beams with elastic couplings has been performed. The analysis includes the effects of transverse shear across beam sections, torsion warping and constrained warping. Reissner's semi-complementary energy functional is used to obtain the beam st illness coefficients The bending and torsion related warpings and the shear correct ion factors are obtained as part of the analysis. The resulting theory describes the beam kinematics in terms of the axial, flap and lag bending, flap and lag shear, torsion and torsion-warping deformations. The static response has been validated against finite element predict ions, closed form solutions, and experimental data for rectangular sol id and I-beams with elastic couplings. The free vibration results are also compared with available literature.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.100-108
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• 1999

rectangular open or in-filled trenches(concrete and rubber) are often used to reduce the ground vibrations caused by propagating surface(Rayleigh) waves. This paper presents the experimental data for estimating the vibration screening effectiveness of open or in-filled trenches Field dynamic tests using the exciter which can generate the 100kN vertical cyclic load in the range of 100-250 Hz were performed. One hundred and twenty accelerometers to measure the ground response are used in 6 radial direction. To compare the effectiveness of the vibration isolation the contours of the amplitude ratio with the dimensionless parameters dividing by Rayleight wave lengths were presented.

• Coupled systems mechanics
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• 제12권1호
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• pp.83-102
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• 2023

First introduced in 2016, the dynamic foundation model is an interesting topic in which the foundation is described close to reality by taking into account the influence of the foundation mass in the calculation of oscillation and is an important parameter that should be considered. In this paper, a follow-up investigation is conducted with the object of the Mindlin plate on a nonlinear dynamic foundation under moving loads. The base model includes nonlinear elastic springs, linear Pasternak parameters, viscous damping, and foundation mass. The problem is formulated by the finite element analysis and solved by the Newmark-β method. The displacement results at the center of the plate are analyzed and discussed with the change of various parameters including the nonlinear stiffness, the foundation mass, and the load velocity. The dynamic response of the plate sufficiently depends on the foundation mass.

• 전기전자학회논문지
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• 제24권1호
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• pp.311-318
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• 2020

가상발전소는 개별 분산자원의 통합 관리를 통해 계통운영에 참여를 가능하게 하는 일종의 소프트웨어 발전소이다. 본 논문에서는 단일 발전시스템으로 가상발전소를 운영하기 위하여 국내 전력시스템 통신에 사용되는 TASE.2(Telecontrol Application Service Element) 표준과 분산자원 관리 기술인 OpenADR(Open Automated Demand Response)2.0 표준을 결합하여 상위 전력시스템과 하위 분산자원을 공통정보모델로 구성한 통신 아키텍처를 제시한다. 분산자원의 기본 형태인 ESS를 TASE.2 SBO(Select Before Operate) 디바이스로 구성하고 관련 오브젝트를 OpenADR2.0 리포트 및 이벤트 서비스와 매핑하여 단일 시퀀스 타입으로 설계한다. 시뮬레이션 검증을 통해 두 표준에 준수한 데이터 교환 및 동작을 확인한다.

• 한국산림과학회지
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• 제87권1호
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• pp.50-56
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• 1998

오존에 약(弱)하거나 저항성(抵抗性)을 가지는 포플러 개체(個體)를 선발(選拔)하기 위해서 36개의 잡종(雜種)포플러 클론을 오존에 노출(露出)시켰다. Open-top chamber를 이용(利用)하여 하루에 6-8시간, 3개월 동안 90-115ppb의 농도(濃度)로 오존을 노출시켰다. 수고(樹高), 직경(直徑), 엽수(葉數), 물질생산량(物質生産量), root/shoot비율(比率), 낙엽률(落葉率), 기공반응(氣孔反應) 조사(調査)하였다. 수고, 직경, 엽수, 물질생산량, root/shoot비율, 기공 conductance는 오존 때문에 감소(減少)하였고, 낙엽률은 증가(增加)하였다. 이 연구에서는 기공 conductance와 물질생산량과의 관계(關係)는 아주 낮게 나타났다. 오존환경(環境)에 대해서 저항성을 갖는 것은 기공(氣孔)의 개폐(開閉)와 항상(恒常) 관계(關係)가 있는 것은 아니라고 사료(思料)되며, 아마도 생화학적(生化學的)이고 생리적(生理的)인 다른 요인(要因)에 대(對)한 연구(硏究)가 포플러 클론이 갖는 저항성을 이해(理解)하는데 도움이 될 것이다.

• 한국지진공학회논문집
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• 제14권5호
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• pp.1-12
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• 2010

본 연구에서는 얕은 연약지반에서 구조물-지반 상호작용의 영향을 받는 구조물의 비탄성거동을 정확히 나타낼 수 있는 유한요소해석 방법을 연구하였다. 이를 위하여, 국내의 지반특성을 반영한 얕은 연약지반과 단자유도 구조물로 2차원 유한요소모델을 구성하고, 다양한 지진파와 지반에 대해 OpenSees 해석프로그램을 이용한 비선형 시간이력해석을 수행하였다. 연약지반의 비선형거동을 반영하기 위하여 일반적으로 흔히 사용되는 등가선형 주파수영역 해석 결과와 비선형 시간이력 유한요소해석 결과의 차이를 검토하였다. 그 비교결과는 등가선형강성을 사용하고 지반-구조물 상호작용을 고려하지 않는 주파수영역해석은 단주기영역의 구조물의 응답스펙트럼을 과대평가할 수 있음을 보여주었다. 응답스펙트럼에 대한 지반-구조물 상호작용의 영향은 기초크기와 구조물의 질량의 변화와 큰 관계 없이 일정하게 나타났다.

• Earthquakes and Structures
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• 제17권4호
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• pp.373-385
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• 2019

In this article, different frequently adopted modeling aspects of linear and nonlinear dynamic soil-structure interaction (SSI) are studied on a pile-supported integral abutment bridge structure using the open-source platform OpenSees (McKenna et al. 2000, Mazzoni et al. 2007, McKenna and Fenves 2008) for a 2D domain. Analyzed approaches are as follows: (i) free field input at the base of fixed base bridge; (ii) SSI input at the base of fixed base bridge; (iii) SSI model with two dimensional quadrilateral soil elements interacting with bridge and incident input motion propagating upwards at model bottom boundary (with and without considering the effect of abutment backfill response); (iv) simplified SSI model by idealizing the interaction between structural and soil elements through nonlinear springs (with and without considering the effect of abutment backfill response). Salient conclusions of this paper include: (i) free-field motions may differ significantly from those computed at the base of the bridge foundations, thus put a significant bias on the inertial component of SSI; (ii) conventional modeling of SSI through series of soil springs and dashpot system seems to stay on the safer side under dynamic conditions when one considers the seismic actions on the structure by considering a fully coupled SSI model; (iii) consideration of abutment-backfill in the SSI model positively affects the general response of the bridge, as a result of large passive resistance that may develop behind the abutments.

• 대한인간공학회지
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• 제32권3호
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• pp.217-227
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• 2013

Objective: The purpose of this study was to analyze 'response time', 'peak response time' and 'overshoot value' for each muscle by applying the EMG signal to the vehicle response in ISO 7401 and to quantify the response of the driver according to vehicle characteristics by comparing vehicle characteristics and muscle responses of the driver. Background: The Open-loop test defined in international standards ISO 7401 is the only method for evaluating the performance of the vehicle. However, this test was focused only on mechanical responses, not driver's ones. Method: One skilled male driver(22 yrs. experience) was participated in this experiment to measure muscle activities of the driver in transient state. Then the seven muscle signals were applied to calculate 'response time', 'peak response time', and 'overshoot value'. Results: In the analyses of the EMG data, the effects of vehicle type and muscle were statistically significant on the 'response time' and 'peak response time'. Also, the effects of vehicle type, muscle, and lateral acceleration level were statistically significant on the 'overshoot value' in this study. According to the analyses of the vehicle motion data, vehicle motion variable(LatAcc, Roll, YawVel) was statistically significant on the 'response time' and vehicle type, vehicle motion variable, and lateral acceleration level were statistically significant on the 'peak response time', respectively. Conclusion: In the analyses of the 'response time' and 'overshoot value', the data of muscle activities(EMGs) was better index that could evaluate the vehicle characteristic and performance than the data of vehicle motion. In case of peak response time, both EMG and vehicle motion data were good index. Application: The EMGs data from a driver might be applicable as index for evaluation of various vehicle performances based on this study.