• 한국기계가공학회지
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• 제15권3호
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• pp.72-78
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• 2016

In this study, we analyzed the accidental hydrogen embrittlement affecting the track nut on a self-propelled howitzer. Tracks are key components to maintain a high degree of confidence in the operation of the self-propelled howitzer and the safety of the crew. This study analyzed the fractured surface using SEM to review accidental damage of the wedge nut. In addition, we conducted revival tests and analyzed the results to identify the cause of the wedge nut damage from hydrogen embrittlement. We should carry out factor analysis and continuous improvement of the manufacturing process to determine the accidental breakage mechanism for future enhancement of the self-propelled howitzer. This study will be the useful reference for enhancing process designs in similar products.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.364-371
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• 2011

This paper presents experimental results and derived experimental equations to investigate the turbulent wake characteristics generated by the self-propelled SUBOFF submarine model. A self-propelled SUBOFF model which was assumed as an axial-symmetric body was used to create wake, and a thin strut was mounted on the topside of the model. The experiments were conducted in a circulating water channel(CWC), and the hot-film was used to measure the turbulence in wake cross-section at the distance range of 0.0~2.0L from the model. The hot film anemometer measured turbulent velocity fluctuations, and the time-averaged mean velocity and turbulent intensity are obtained from the acquired time-series data. Measured results show well the general characteristics of turbulent intensity, kinetic energy and mean velocity distribution. Also, this paper presents derived experimental equations, which is extended result to the reference [1]. These experimental equations show well the general characteristics of the turbulent wake behind the self-propelled submerged body.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.76-82
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• 2015

Active matter는 스스로 에너지를 가지고 움직이는 개체들이 서로 상호작용을 하여 집단적인 움직임을 보이는 물질이다. Rotational noise model은 반발 상호작용과 rotational noise를 가지고 있는 self-propelled particle로 active matter를 설명한다. 이 연구에서는 rotational noise model에서의 상 도표와 클러스터 형성을 알아보고 입자들의 집단적인 운동을 도와주거나 방해할 수 있는 leader 입자와 seed가 클러스터의 운동에 어떠한 영향을 주는지 알아본다.

• Journal of Biosystems Engineering
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• 제21권4호
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• pp.406-413
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• 1996

A control system for a self-propelled boom sprayer to spray at uniform application rate was developed and evaluated. The ground speed of the sprayer was converted into voltage. The voltage was used as an input signal. Output signal was current of a servo motor, that controlled application pressure of the sprayer with a feedback control system. Spraying was executed at the pressure of 20~55 psi and the speed of 0.640~0.696 km/hr and 1.040-1.131 km/hr. Although the pressure and the speed of sprayer were changed continuously, application rate was tried to keep a nearly constant amount of 666.67 L/ha. This result showed that the developed control system for uniform application rate was adoptable for the self-propelled sprayer.

• 한국군사과학기술학회지
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• 제3권1호
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• pp.26-37
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• 2000

This research paper deals with the problem of determining the optimal life time in terms of economical sense for a self-propelled artillery. Equivalent Annual Cost Method(EACM) is used to evaluate the optimal life time, based on the acquisition cost, and the operation and maintenance cost. It is assumed that the operation and maintenance cost includes the costs for spare parts, petroleum and ammunition for training. From the result of this study, the optimal life time for a self-propelled artillery is between 13.9 years and 16.1 years with 95% confidence interval.

• 한국건설순환자원학회논문집
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• 제8권3호
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• pp.372-378
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• 2020

본 연구에서는 콘크리트 하수관로의 결함부를 보수하기 위한 자주차의 개발 및 성능평가에 관한 연구를 수행하였다. 비굴착 방식인 자주차를 활용한 하수관로 보수를 위하여 구동 시스템, 보수 유닛 설계 및 보수재료 압송에 관한 성능을 고려하여 자주차를 개발하였다. 개발된 자주차의 성능평가를 하기 위하여 직경 500mm 콘크리트 하수관로에 결함부를 모사하여 보수실험을 수행하였다. 이후, 보수가 완료된 하수관로를 양쪽 끝단과 결함부에 플러그를 삽입하여 고정하고, 물을 주입하여 보수부위에서 누수 여부를 통한 수밀성능을 평가하였다. 누수량은 0.07L/㎡으로 허용 누수량 0.2L/㎡ 이하의 값을 나타내며 우수한 수밀성능을 나타내었다. 따라서 본 연구에서 개발한 자주차는 우수한 보수성능을 나타내는 것으로 판단된다.

• Journal of Biosystems Engineering
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• 제21권1호
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• pp.34-43
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• 1996

The present pesticide application technology widely used with a power sprayer in Korea is assessed as the problem awaiting solution in the point of view of its ineffectiveness, inefficiency, and environmental contamination. As one approach to get rid of these problems, the boom spraying with ultra-low volume and precision application technology has been recommended. The study was undertaken to investigate plants damages incurred by the self-propelled boom-sprayer vehicle, to develop the design criteria of vehicle wheel, and to compare plant damages caused by the front wheel steering vehicle, the 4-wheel drive vehicle and the articulated vehicle, by the computer simulation. The experiment showed that the amount of damaged plants incurred by the self-propelled boom sprayer were about 0.29% in average in the field size of 100m$\times$50m(0.5ha), about 60~80% of which recovering while growing. The recommandable wheel size was analyzed to be 70~100cm in diameter, 8~15cm in width from the vehicle-plant-soil relationship. The simulation on damaged plants anticipated to be incurred by various steering vehicles showed that the smaller the turning radius, the lesser the damaged plants within its range of 3~5m. Average plant damage rate by the front wheel steering vehicle, the 4-wheel drive vehicle and articulated vehicle was relatively assessed to be 2 : 1.8 : 1.

• 한국전자통신학회논문지
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• 제16권5호
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• pp.889-898
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• 2021

현재 대한민국의 인구절벽 현상으로 인한 한국군의 군 병력부족으로 대한민국의 심각한 국방 공백이 발생될 수 있는 상황이다. 따라서 인구감소로 인한 대한민국의 국방 공백을 해결하기 위해 한국군은 보병을 제외한 기계화 부대에 재편된 인원을 축소시키고 자율주행화하여 국방 공백을 상쇄해 유사시 북한군이 한국군에게 행할 수 있는 군사적 도발 및 선제공격에 대비하는 정책을 펼칠 가능성이 있다. 본 논문에서는 우리 군이 기계화 부대에 재편된 자주포와 같은 무기체계들에 있어 자동화와 자율주행화로 인원을 감축시킬 때 K-9자주포의 자율주행 및 진지 배치에 관한 운용 가능성을 확인하고 K-9자주포의 자율주행화와 이에 따른 운용방법과 그 필요성 및 타당성을 간단한 자율주행이 가능한 K-9자주포 모형 로봇으로 위의 내용을 모사하여 설명하였다. 그리고 자율주행이 가능한 실제 K-9자주포를 실전에 배치하였을 때 나타날 수 있는 문제점을 예측하여 서술하였다.

• 대한기계학회논문집
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• 제17권5호
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• pp.1041-1053
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• 1993

본 연구에서는 2차원 절삭중 공구가 공작물로 들어가는 과정에서의 칩형성의 천이적 행동을 실험적으로 연구하고 이 결과를 이용하여 자기추진 로타리 공구를 사용 한 절삭중 발생한 칩의 삼각화 과정을 규명하는 이론적인 모델을 제안하고 이의 타당 성을 실험결과로 입증하려 한다.

• 한국기계기술학회지
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• 제20권6호
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• pp.836-843
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• 2018

In this paper, dynamic model of 120mm self-propelled mortar is developed, and multi flexible body dynamics analysis is performed to analyze stresses occurring in the mount during mortar fire. For this, vehicle dynamic system, mortar dynamic system, and finite element mount model are proposed. The commercial program Recurdyn is used in the analysis. As a result of the analysis, the maximum stress(146.9MPa) occurred at the mount side plate. In order to analyze the validity of the analysis results, we performed strain measurement tests by selecting three major points, and the errors of results were 7.91%, 11.15%, and 18.23%, respectively. It is confirmed that the tendency of analysis and test is similar.