• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.262-266
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• 2014

Military vehicle equipped with an antenna and a shelter for operating radar has a vibration exposure during driving time. This vibration would have influence on structure of military vehicle critically. In this paper, driving stability of the military vehicle is obtained through the vibration response analysis. And, vibration level of the military vehicle satisfied the military vibration specification through analysis and comparing the MIL-STD-810G. PSD and Grms data obtained by road test can be used for vibration test specification of cabinets and electronic equipment in shelter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.424-429
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• 2013

The trolley carrying the pod moves along by the airfield runway. The pod through the trolley are subjected to vibration arising from the ground state, the precision optical components in the pod can have a significant impact. The road tests were conducted by using the measurement pod to remove the risk for the project. The measurement pod was composed with the ACRA, sensors, battery. The accelerometers were attached to get the acceleration through the road condition. The PSD envelop was calculated by FFT from the acceleration. The driving safety was proven through comparing the measurement data and MIL-STD-810G specification.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.94-99
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• 1994

최근 인구의 과밀화와 이에 따른 지가의 상승 등으로 대표적인 주거용 빌딩인 아파트의 고층화가 급속하게 진행되고 있고 아파트에 설치되는 엘리베이터도 점차 대형화, 고속화 되고 있다. 실례로 15층 아파트의 경우 11인승, 60m/min의 엘리베이터가 일반적으로 사용되는 반면, 20층 아파트의 경우 17인승, 90m/min이 주로 사용된다. 이와 같이 엘리베이터의 용량과 운행 속도가 증가함에 따라 필연적으로 소음 및 진동 문제가 발생하게 된다. 특히 아파트의 경우 침실, 공부방 등 고도의 정숙을 요하는 생활 공간이 많고, 내부 공간의 활용도를 높이기 위하여 이들 방들이 엘리베이터 기계실 또는 운행 통로와 직접 접하여 있는 경우도 있어 이 경우 소음, 진동 문제는 아주 심각한 문제로 대두된다. 본 연구소가 측정한 방에 의하면 S신도시 L아파트의 경우 아파트 최상층 방에서 실내 소음도가 46dB(A), 벽의 진동가속도가 3.4mm/s$^{2}$(RMS)으로 나타났다. 진동의 경우 생활에 직접적인 악영향을 미칠 수준은 아니지만 소음의 경우 ASHRAE 권장 주택소음 기준치가 35dB(A) 이하임ㅇㄹ 감안하면 주거에 곤란한 수준이다. 수년전, 고층 아파트가 보급될 초기에는 아파트에 엘리베이터가 설치되어있다는 그 자체만으로 충분한 장점이 되어 다소음 소음, 진동문제는 큰 불만거리가 되지 않았지만 엘리베이터가 보편화된 지금에는 엘리베이터의 편리성만으로는 점점더 크게 요구되는 정숙성이 보상되지 않는다. 따라서 전반적인 아파트의 소음, 진동 문제에 큰 비중을 차지하는 엘리베이터에 의한 소음, 진동에 관하여 체계적인 연구가 필요하다. 이에 본고에서는 엘리베이터에 의한 아파트의 소음 및 진동에 관하여 그 현황, 원인 그리고 대책에 관한여 논하고자 한다.감 방법을 연구하였고, T.Sakai는 5자유도 모델을 이용하여 엔진 공회전시 발생하는 치타음에 대해 이론과 실험을 통해 해석하고, 엔진 회전수 변동, 클러치 특성, 변속기의 드래그(drag) 토크의 영향과 치타음 저감을 위한 개선된 클러치 특성을 제시하였다. 이 외에도 Thomas C.T.와 E.P.Petkus는 특정 차량에 대한 동력전달계의 비틀림 진동 현상에 대해 연구하였다. 이러한 연구들로 볼 때, 자동차 동력전달계에서 발생하는 진동은 이론과 실험을 통해 그 해석이 가능하며 설계에 매우 유용하게 이용되고 있음을 알 수 있다. 따라서, 본 연구는 4 실린더 4 싸이클 1.5 L 엔진을 장착한 경승용차의 실차 주행실험을 통해 가속 페달의 급조작에 따른 차체의 종진동 현상을 측정하고, 엔진-변속기-타이어-차체의 반환정계 4자유도 진동모델로 시뮬레이션을 수행하여 실차 주행실험의 결과치와 비교, 분석한 후 클러치 비틀림 특성을 비롯한 자동차 동력전달계의 각 설계인자들이 차체의 종진동에 어떠한 영향을 미치는가를 해석하고자 한다.be presented.LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다._3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과 0.05 - 0.1

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.871-875
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• 2001

Evaluation of the contribution of each pass-by noise source to the overall pass-by noise is an important issue for reduction of pass-by noise. A lead-wrapping test for analyzing pass-by noise of motorcycle is used to identify the principal noise sources of the pass-by noise in this study. Lead-wrapping test is employed and the contribution analysis is carried out. Based on the contribution analysis of each pass by noise source from the action of the prior tests, the design modifications of intake/exhaust systems were performed for reducing the pass-by noise. Finally, the pass-by noise test based on ISO362 was carried out to verify the noise reduction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.323-334
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• 2008

According to the delivery condition, the breakage of a product occurs when it is delivered to the customers. Therefore product's makers evaluate the durability under the delivery process by accelerated life testing. In order to conduct this accelerated life testing accurately, it is very important to identify the acceleration-factor exactly between on-road and accelerated life test condition. In this paper, the acceleration-factor is identified by applying linear damage summation law, rain-flow cycle counting and Dirlik theory under the conditions of the random vibration. And approximated FEM model of the connecting-pipe to the compressor is developed for fatigue analysis. This model is finally verified by comparing the experiment results to the numerical analysis results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.39-43
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• 1995

대형 상용차용 내연기관에서 방출되는 소음의 음압 레벨은 경우에 따라 140dBA 이상으로 환경소음 배출규제에 부합되는 배출 소음을 위하여는 소음기의 적절한 설계가 필요하다 하겠다. 소음기는 방출 소음을 저감시키는 기본적인 작용 이외에 엔진의 효율을 저하시키는 배압(back-pressure) 상승의 효과를 동반할 뿐만 아니라 차체에의 장착을 위하여 크기와 무게의 제약을 받는다. 따라서 소음기는 설계자의 경험과 과거에 사용되어 온 소음기에 대한 이해, 소음기를 구성하는 단위 요소에 대한 음향학적 해석이론, 제작 과정에서의 경험과 튜닝 등에 바탕을 두고 설계되어져 왔다. 본 연구에서는 대형 상용차에 장착되는 기존 소음기 구성요소의 투과 손실(Transmission Loss: TL)을 전달 행렬법으로 해석하여 음향학적 특성을 규명하고 개별 소음기 요소에 대한 기존의 연구 결과를 바탕으로 공명기와 다공 요소를 이용하여 기존 소음기를 재설계함으로써 배출 소음의 저감을 이루어 나간 과정을 소개하고 이를 적용 사례를 중심으로 살펴보고 있다. 소음기의 설계를 위하여 고려할 수 있는 음향학적 요소는 그 기능과 형태면에서 다양하나 본 연구에서는 대형 상용차용 소음기에 주로 사용 가능한 공명기와 다공관을 주된 설계요소로 생각하였다. 공명기는 공명 주파수 대역의 소음을 저감하는 역할을 하므로 일정한 엔진 회전수 하에서 엔진의 방출 소음중 폭발 성분에 의한 소음을 줄이는데 효과적으로 사용될 수 있지만 가속 주행시에는 회전수(rpm)의 변화에 따라 폭발 주기가 변화하게 되므로 공명기의 설계에 주의를 기울여야 한다. 내연 기관용 소음기에 빈번하게 쓰이는 다공 요소의 해석 방법으로는 Sullivan[1], Kim and Yoon[2] 등의 분할 접근 방법(Segmentation approach)과 Jayaraman and Yam[3], Munjal[4], Peat[5] 등의 연성 제거 방법(Decoupling Approach)등이 제시되었고 평면파 영역에 한하여 해서되어져 왔다. 본 논문에서는 분할 접근 방법(Segmentation Approach)을 이용하여 다공 요소로 이루어진 소음기를 해석하는데 적용하였다.

• Journal of KSNVE
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• v.4 no.3
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• pp.353-363
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• 1994

The non-preiodic fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration hs become a significant problem along with the requirements of higher performance. The shuffle(tip-in, tip-out) is the transient vibration phenomenon of a vehicle which appears at the sudden change of an accelerator under traveling. By executing of an experiment and a simulation using a model, it has become possible to obtain the design parameter of a driveline for the torsional vibration. This paper presents an experimental and theoretical research on the transient vibration phenomenon of a vehicle which appears at the sudden change of an accelerator under traveling. A dynamic model for the automotive driveline was developed, and all parameters of the mmdel were evaluated with experimental data. The results are as follows: (1) The lower the gea ratio of the transmission is, the more the transient vibration phenomenon of a vehicle appears clearly. (2) The transient vibration phenomenon of a vehicle is affected by the design parmeter of the driveline.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.717-724
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• 2017

To improve the running safety of a tram operating on a concrete embedded track, a bogie, the core system of the tram, was developed and fabricated. After it was integrated with the prototype car body, a short distance track with a sharp curve and steep gradient was constructed for the test operation. A formula to check the interference of the wheel flange with the track during running was proposed. Based on the results provided by the formula, the track was designed. Another simple formula was derived to estimate the derailment quotient and the wheel unloading ratio. During running on the track, the acceleration of the car body was measured and the interface status between the wheel and the track was monitored by a video system. According to the results calculated by these simple formulas, the derailment quotient and wheel unloading ratio were estimated to be within the safety criteria. In the actual test, no derailment occurred and the measured acceleration satisfied the criteria. Also, there was no interference between the wheel and track. The video monitoring results showed no signs of derailment, such as the climbing of the wheel. The pinion in the center showed good running safety, contacting smoothly with the rack. The measurements of environmental noise proved that the criteria were satisfied.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.332-347
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• 2017

Analysis of the interaction between the automated vehicles and manual vehicles is very important in analyzing the performance of automated cooperative driving environments. In particular, the automated vehicle platooning can affect the driving behavior of adjacent manual vehicles. The purpose of this study is to analyze the lane change behavior of the manual vehicles in automated vehicle platonning environment and to conduct the experiment and questionnaire surveys in three stages. In the first stage, a video questionnaire survey was conducted, and responsive behaviors of manual vehicles were investigated. In second stage, the driving simulator experiments were conducted to investigate the lane change behaviors of in automated vehicle platonning environments. To analyze the lane change behavior of the manual vehicles, lane change durations and acceleration noise, which are indicators of traffic flow stability, were used. The driving behavior of manual vehicles were compared across different market penetration rates (MPR) of automated vehicles and human factors. Lastly, NASA-TLX (NASA Task Load Index) was used to evaluate the workload of the manual vehicle drivers. As a result of the analysis, it was identified that manual vehicle drivers had psychological burdens while driving in automated vehicle platonning environments. Lane change durations were longer when the MPR of the automated vehicles increased, and acceleration noise were increased in the case of 30-40 years old or female drivers. The results from this study can be used as a fundamental for more realistic traffic simulations reflecting the interaction between the automated vehicles and manual vehicles. It is also expected to effectively support the establishment of valuable transportation management strategy in automated vehicle environments.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.363-371
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• 2009

The purpose of this study is to verify the safety issue of the tinted vehicle based on the field study as well as the issue of the capacity reduction from the tinted vehicle. Through this study, an innovative experimental method to verify the issues was developed using RTK GPS receivers, and a data collection was conducted using the developed experimental method. Using the collected data, the effects of the ahead vehicle with the windows tinted on the traffic condition such as headways and acceleration noise were analyzed to test that the ahead vehicle with windows tinted too darkly affects the increasing vehicle maneuver as following the degree of tinting. This study was conducted as a frontier study and more studies, for example, full scale analyses considering various road and vehicle conditions need to be conducted in the future.