모듈형 LNG Tank의 외조를 구성하는 SCP(sandwich concrete panel)에 대해서 중속충돌시험기로 충돌시험을 수행하고 이에 대한 수치해석을 수행하였다. 충돌시험에 사용된 시험체는 가로세로 각각 2m로 외조의 일반단면과 연결부단면의 특성을 가지도록 제작하였다. 51kg의 탄자를 설계기준에 규정된 충돌에너지를 갖도록 중속충돌시험기로 45m/sec로 이상의 속도로 가속하여 충돌시켰다. 이런 충돌시험을 두 차례 반복하고 시험체의 극한능력을 평가하기 위하여 충돌속도를 2배로 하여 충돌시켰다. 충돌시험의 수치해석 모델은 LS-DYNA를 이용하여 수행되었다. 외측의 강판와 그 사이의 충진콘크리트를 고 체요소로 모델링하고 전단연결재는 보요소를 이용하여 모델링하였다. 강재의 재료모델은 탄소성 및 파단거동을 고려하였으며 콘크리트의 재료는 CSCM재료로 모델링하였다. 해석에서 전면부의 충돌변형은 시험에서 얻어진 변형과 유사한 값을 얻었으나 후면부의 변형은 시험결과와 다소 작은 값을 보였다. 일반부 단면에 대한 2배속 충돌시험에서는 전후면의 강판이 파 손되었으나 해석결과에서는 전면부의 강판만 파손되었다. 수치해석에서 충돌에너지는 주로 충진 콘크리트로 전이되었는데 이는 이전 연구에서 보였던 고에너지를 가진 충돌의 경우와 다른 경향이다. 작성된 모델은 구조적으로 보수적인 결과를 보 이므로 실제 설계에 적용할 수 있을 것으로 판단된다.

An experimental investigation is performed to study the effect of jet to plate spacing and low Reynolds number on the local heat transfer distribution to normally impinging submerged circular air jet on a smooth and flat surface. A single jet from a straight circular nozzle of length to diameter ratio(l/d) of 83 is tested. Reynolds number based on nozzle exit condition is varied between 500 and 8,000 and jet to plate spacing between 0.5 and 8 nozzle diameter. The local het transfer characteristics are obtained using thermal images from infrared thermal imaging technique. It was observed that at lower Reynolds numbers, the effect of jet to plate distances covered during the study on the stagnation point Nusselt numbers is minimal. At all jet to plate distances, the stagnation point Nusselt numbers decrease monotonically with the maximum occurring at a z/d of 0.5 as opposed to the stagnation point Nusselt numbers at high Reynolds numbers which occur around a z/d of 6.

해상에서 두 척의 대형 해양경찰 함정을 이용하여 충돌 가능성이 높은 네 가지 조우방위각(000°, 045°, 090°, 135°)을 설정하여 피험자인 30명의 해양경찰관을 대상으로 조우방위별 거리 3해리(Nautical Mile: NM)에서부터 0.25 NM까지 근접하며 상대거리가 점차 감소 될 때 피험자들이 상대선박을 보며 지각한 충돌위험도(Perceived Ship Collision Risk, PSCR)를 측정(0.25 NM 간격으로 기록)하는 실험을 하였 고 획득된 데이터를 이용하여 특징을 통계적으로 분석하였다. 본 연구의 목적은 인적오류 예방을 위하여 실선 실험한 선박 조우방위별 상 대거리 3 NM에서 0.25 NM까지의 열두 구간에서 획득한 충돌위험도 값을 적정 다항식으로 곡선 근사(Curve Fitting)하여 분포곡선으로 나타 내고 특징을 분석하여 항해당직자들이 지각한 충돌위험도의 변화가 최대인 거리를 제시하기 위한 것이다. 분석결과, 각 조우방위에서 거리 구간별 최적의 회귀방정식을 도출하였으며 거리 1.25 1 NM 구간에서 충돌위험도 평균값의 편차가 가장 크게 변화되었고, 특히 1 NM에서 충돌위험도 값이 가장 크게 나타나 실선 실험결과 항해당직자가 지각(Perception)한 충돌위험도의 변화 값이 최대인 거리가 1 NM임을 도출 및 검증하였으며 이는 선박 충돌가능성이 높은 근접상황에서 인적오류 예방 자료로 유용할 것으로 기대된다.

The heat transfer of Jet impingement is a very effective technique for exchanging high heat fluxs between a heated plate and a fluid. The purpose of current investigation is to carry out the experiment in order to study heat transfer characteristics between a vertical round water jet and a horizontal surface for different flow rates and geometric conditions. The effect of flow rates on heat transfer were investigated. The data obtained in this study are represented in terms of Nusselt number as a function of Reynolds and Peclet numbers. The correlation for the Nusselts number in terms of the Peclet number and  was obtained. The proposed correlation predicts the current data of heat transfer very well.

This paper presents development of the new haptic device for virtual wall collision test. Mathematical model of the proposed system considering virtual wall collision is developed and tuned by comparing force responses from simulation and experiment with free motion. To verify the effectiveness of the proposed model, a range of collision tests against virtual wall are accomplished, conditioned on different collision speeds to virtual wall. In addition, hybrid PI control scheme is applied to improve the performance of the proposed haptic system in virtual wall collision experiments.

According to a statistics, a number of traffic accident by bridge pier and independent fixed object crash accident has been increased. we evaluated a car damage and passenger injury through vehicle accident reconstruction test of independent fixed object crash accident. A damage of crash accident car based on accident investigation report was similar to demage of 27km/h reconstruction test car, and therefore we can find the speed of crash accident car is 20km/h～30km/h. It is very low that the skull fracture and injury possibility of AIS 4 above in 37km/h and 27km/h reconstruction test car. It is very high that injury possibility in 70km/h reconstruction test car. Also, it is not high that impact of the driver and passenger's lower body(thigh, shin, ankle) in 37km/h and 27km/h reconstruction test car. On the other hand, it is very high that impact of head, chest and thigh of the driver and passenger in 70km/h reconstruction test car.

In this study, preliminary analytical study on the middle scale impact test of SC(steel plate concrete) walls were carried out to evaluate the impact resistance performance of SC walls subjected to missile impact load. A total of 15 middle-scale impact tests will be carried out to investigate the impact behavior of SC walls. Pre-test impact analysis for all test cases were performed to decide the initial impact velocity. Calibrations of the analytical parameter were performed using preliminary test results.

In this study, experimental study on the missile impact behavior of the nuclear power plant SC(steel plate concrete) wall was carried out to set up the future direction for the reasonable design method development. Four set of actual impact test of the SC wall were conducted at the EMRTC site located in Socorro, New Mexico. Initial and residual velocity of the missile, strain and acceleration of the back plate, local failure mode and deformation size, etc. were measured to study the local failure behaviour of the specimens. Finally, the experimental results are compared with the local failure evaluation formula and future research direction for the refined design method of the SC wall was reviewed.