폭발해석을 위한 간략 폭발하중 제안식

전두진,한상을,Jeon, Doo-Jin,Han, Sang-Eul 한국전산구조공학회 2016 한국전산구조공학회논문집 Vol.29 No.1

본 논문에서는 폭발해석에서 주로 사용되는 폭발하중의 압력-시간 이력곡선과 폭발하중 산정식인 Conwep 모델을 소개하고, 이를 더욱 간편하게 계산할 수 있는 간략 폭발하중 산정식을 제안한다. 폭발해석에서 폭발하중은 일반적으로 압력-시간 이력곡선의 형태로 적용되며, 그에 대한 주요 값들은 폭발하중 산정식에 의해 계산된다. 대부분의 폭발해석에서 사용되는 폭발하중 산정식인 Conwep 모델은 환산거리(scaled distance)를 핵심변수로 하여 계산되는데, 그 계산 과정이 매우 복잡한 단점이 있다. 따라서 본 논문에서는 환산거리를 변수로 갖는 간략한 유리식을 사용하여 주요 값들을 계산하고, 단순화된 압력-시간 이력곡선으로 폭발하중을 산정할 수 있도록 제안하였다. 간략식을 찾는 과정에서 Conwep 모델의 계산 결과를 바탕으로 곡선 적합(curve fitting) 방식이 사용되었으며, 제안된 간략식에 의한 주요 값의 계산 결과는 Conwep 모델과 비교하여 1% 미만의 오차를 갖는다. 또한, 유한요소를 이용한 폭발해석에 적용하였으며 Conwep 모델을 적용한 결과와 비교를 통해 검증하였다. In this paper, a pressure-time history curve of blast load and Conwep model are presented, and a simplified blast load formula is suggested. Generally, a blast load are applied as a pressure-time history curve, and it is calculated by blast load formula such as Conwep model. The Conwep model which is used in most of the blast analysis is quiet difficult to calculate because of its complex process. Therefore, a simplified formula is proposed to calculate blast load by simple rational expressions and to make a simplified pressure-time history curve. In this process, a curve fitting method was used to find the simple rational expressions. The calculation results of the simplified formula have an error of less than 1% in comparison with the Conwep model. And, blast analyses using finite elements method are accomplished with the Conwep model and simplified formula for verification.

CFD 시뮬레이션을 이용한 풍하중 산정 시 변동풍속 프로파일에 관한 연구

전두진,한상을,Jeon, Doo-Jin,Han, Sang-Eul 한국공간구조학회 2021 한국공간구조학회지 Vol.21 No.1

In this paper, the effect of the turbulence intensity in across-wind direction on the wind load in CFD(Computational fluid dynamics) simulation was analyzed. 'Ansys fluent' software was used for CFD simulation. And the fluctuating wind speed applied to the simulation was generated according to Korean Design Standard and Von Karman wind turbulence model. The turbulence intensity in across-wind direction for simulation was applied from 0 to 100% of the turbulence intensity in along-wind direction. The analysis results showed that the turbulence intensity in across-wind direction had a particularly great effect on the wind load in across-wind direction.

자유 공중 폭발하중 파라메타의 수정 산정식

전두진,이민재,한상을,Jeon, Doo-Jin,Lee, Min-Jae,Han, Sang-Eul 한국공간구조학회 2016 한국공간구조학회지 Vol.16 No.4

The blast load is classified into free-air blast and surface blast following the location of explosion and surface. In this paper, several equations for blast load calculation are explained briefly and a modified equation for free-air blast load is suggested. The modified equation is based on Kingery-Bulmash equation which is used in UFC 3-340-02 and Conwep model. In this modified equation, the process of calculation is simplified against the original equation, and the number of coefficients is reduced under 5. As a result, each parameter of estimated data by modified equation has less than 1% of error range comparing with Kingery-Bulmash equation.

철골 프레임의 폭발 및 연쇄붕괴해석을 위한 효율적 모델링 기법

전두진(Jeon, Doo-Jin),차은호(Cha, Eun-Ho),한상을(Han, Sang-Eul) 대한건축학회 2015 大韓建築學會論文集 : 構造系 Vol.31 No.9

The blast analysis is limited to unit members because of its long analysis time. So this paper proposes the effective modeling and simulation technique for blast and collapse analysis of steel frame. In this study, analysis for static and blast load are performed with three kinds of elements such as solid element, plate element and thick plate element. Then, the most efficient element for blast and collapse analysis is determined by comparing the reliability of the results and calculation time. Also, quasi-static is applied to the analysis that has to be carried out by the static and dynamic analysis. The analytical models are the beam(H-294x200x8x12) and column(H-200x200x8x12). As the result, a thick plate element is most efficient for blast analysis. Through this way, blast and collapse analysis are simulated with the imaginary steel frame.

자유 공중 폭발하중의 수정 산정식

전두진(Jeon, Doo-Jin),한상을(Han, Sang-Eul) 대한건축학회 2016 대한건축학회 학술발표대회 논문집 Vol.36 No.2

가스 폭발하중을 받는 콘크리트 돔 구조물의 안정성 평가

전두진(Jeon, Doo-Jin),김효진(Kim, Hyo-Jin),이경수(Lee, Kyung-Soo),고훈범(Ko, Hune-Bum),한상을(Han, Sang-Eul) 대한건축학회 2014 대한건축학회 학술발표대회 논문집 Vol.34 No.2

충돌/폭발 하중에 의한 구조물의 파괴거동 해석

한상을,전두진,차은호,Han, Sang-Eul,Jeon, Doo-Jin,Cha, Eun-Ho 한국공간구조학회 2016 한국공간구조학회지 Vol.16 No.3

충돌해석을 통한 볼라드의 성능평가 및 설치기준 제안

차은호,전두진,한상을,Cha, Eun-Ho,Jeon, Doo-Jin,Han, Sang-Eul 한국공간구조학회 2016 한국공간구조학회지 Vol.16 No.4

Recently damage of structures and loss of life by terrorism are internationally increasing. Among these terror that have a possibility to can happen in korea and that can caused lot of human life loss is the vehicle terror. To prevent the vehicle terror, the anti-ram barriers are needed. But domestic standard about anti-ram barriers are not clear. So, in this study, we will utilize and analyze the vehicle impact to evaluate the efficiency of the domestic bollard and suggest the installation standard of those. In Korea, granite, elastic, steel and stainless bollard are used. The performance of those bollard is not available. Elastic bollard couldn't stop the vehicle, and the others just could stop the vehicle only at the speed under 10kph. Therefore, set the variable to reinforce, and evaluate the defence efficiency of bollard. As a result, granite and elastic bollard was not suitable for the anti-ram barriers. Performance of steel bollard increased as thickness grew. So steel bollard should must be thicker than 10T. And the concrete compressive strength effected insignificantly on the defence efficiency, so more than 24MPa compressive concrete be used. Performance of stainless bollard increased as thickness grew. So stainless bollard should must be thicker than 13T.

고강도 콘크리트에 대한 간이 인발시험법 적용

고훈범,전두진,이민재,Ko, Hune-Bum,Jeon, Doo-Jin,Lee, Min-Jae 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 논문집 Vol.21 No.5

1970년대에 여러 연구자가 시제품 시험장비를 가지고 인발시험을 실시하였으며, 인발시험은 콘크리트 강도를 결정하는 신뢰할 만한 비파괴검사 방법(NDT)으로 입증되었다. 우리는 고강도 콘크리트 강도를 추정하기 위하여 직경 10 mm볼트에 홈이 파인 파단형 인발 볼트와 인발너트, 그리고 로드셀이 필요 없는 오일 유압펌프를 포함한 간이 인발시험법을 제안하였다. 저비용, 간편성 및 편의성을 갖는 간이인발시험의 이점을 검증하기 위하여, 30 MPa 및 50 MPa 급 두가지 유형의 콘크리트로 제작된 4개의 모의벽체를 대상으로 로드셀을 장착한 간이인발시험을 사용하여 인발시험을 실시하였다. 인발하중과 콘크리트 압축강도는 재령 7일까지는 매일, 그리고 14일, 21일, 28일에 측정되었다. 시험결과 인발하중과 콘크리트 압축강도는 매우 밀접한 상관관계를 보여주었으며 따라서 인발하중이 현장에서 구조물의 고강도 콘크리트 강도를 평가할 수 있다는 것을 확인할 수 있었다. 파단형 인발볼트 직경과 콘크리트 강도와의 관계식으로 y=0.05x+3.79(x=콘크리트 압축강도, y=파단형 인발볼트 직경)이 도출되었으며 결정계수는 0.88로 나타났다. In the seventies, a number of researchers carried out experiments on pullout tests with prototype equipment, and the pullout test was certified as a reliable nondestructive testing(NDT) method for determining the strength of concrete. To estimate the strength of high-strength concrete, we propose a simplified pullout test that uses as a break-off bolt a standard 10mm bolt with a groove on the shaft, an insert nut, and a pullout instrument that includes a hydraulic oil pump without a load cell. To verify the advantages of the simplified pullout test(low cost, simplicity, and convenience), four wall specimens were tested with two levels of concrete strength, 30 MPa and 50 MPa, using a simplified pullout tester with a load cell. The pullout load and concrete compressive strength were measured every day until day 7, day 14, day 21 and day 28. It was found that the pullout load was very similar to the compressive strength. Therefore, we have verified that a simplified pullout test can be used to evaluate the in-place strength of high-strength concrete in structures. The prediction equation of the groove diameter of the break-off bolt(y) with the concrete strength(x) was derived as y=0.05x+3.79, with a coefficient of determination of 0.88 found through regression analysis.

항공연료 질량을 고려한 대형항공기 충돌하중모델의 개발

이경수,하크 지아올,전두진,한상을,Lee, Kyoung-Soo,Huque, Ziau,Jeon, Doo-Jin,Han, Sang-Eul 大韓建築學會 2014 大韓建築學會論文集 : 構造系 Vol.30 No.8

In this paper, the aircraft impact force models of large commercial B747 aircraft were developed by using so called Missile-Target Interaction Method. The Lagrangian meshfree SPH concept was adopted to the fuel mass for impact force calculation. 240ton, 320ton, 420ton of aircraft mass were considered to meet with the previously proposed aircraft impact force model by OECE/NEA(2002) and Arros & Doumbalski(2007). The model of present studies are based on the model of OECE/NEA originally, and extended to the model of Arros & Doumbalski. To calculate and evaluate the aircraft impact force, the impact analyses were simulated by using commercial Hydrocde AUTODYN considering the fuel mass effect. The resultant reaction force of symmetric rigid wall is considered as the impact force of aircraft. The preparation of refined FE mesh and impact simulation were done by using AUTODYN. The aircraft and fuel debris and secondary trajectory effects were considered by the eroding effect on the FE shell element and the explicitly modeled fuel mass. To evaluate and verify the impact force of aircraft, the Riera approach were used for the reference impact time history graph. The rigid wall impact test shows that the finite element model of a B747 which considering the explicit fuel mass effect is good agreement with reference values and the applicability of fuel modelling approaches of this study.