• 한국정밀공학회지
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• 제28권5호
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• pp.559-564
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• 2011

For the safety of railway, it should be evaluated for the running safety by measuring the derailment coefficient. Although railway has run the fixed and maintained rail, some of railway is derailed. This report shows the results that performed the static load test, main line running test on the basis of the derailment theory and experience. It is executed main line test into more than 90km/h for estimating the curving performance and running safety of depressed center flat car of 3-axle bogie. As the test results, could confirm the curving performance and running safety of depressed center fiat car of 3-axle bogie from the results of the wheel unloading, lateral force, derailment coefficient etc. Derailment coefficient was less than 0.6, and lateral force allowance limit and wheel load reduction ratio were enough safe.

• 한국생산제조학회지
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• 제18권6호
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• pp.642-651
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• 2009

The history of excavator design is not long enough which still causes most of the design considerations to be focused on static analysis or simple functional improvement based on static analysis. However, the real forces experiencing on each component of excavator are highly transient and impulsive. Therefore, the prediction and the evaluation of the movement of the excavator by dynamic load in the early design stage through the dynamic transient analysis of the excavator and ensuring of design technique plays an importance role to reduce development-cost, shorten product-deliver, decrease vehicle-weight and optimize the system design. In this paper, Commercial software DADS and ANSYS help to develop the track model of the crawler type excavator, and to evaluate the performance and the dynamic characteristics of excavator with various simulations. For that reason, the track of crawler type excavator is modelled with DADS Track Vehicle Superelement, and the reaction forces on the track rollers were predicted through the driving simulation. Also, the upper frame and cabin vibration characteristics, at the low RPM idle state, were evaluated with engine rigid body modelling. And flexibility body effects were considered to determine the more accurate joint reaction forces and accelerations under the upper frame swing motion.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.447-454
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• 2000

As the AGT system has never operated in Korea, the construction of test track is essential to the acquisition of safety for the passengers. However, the test track is a synthetic system including vehicle, power system, signalling, track etc, several factors must be considered. In this paper, we suggest the general guideline for the test track of AGT system and test items on test track through the investigation of leading test facilities in the world. Through continuous study and investigation, we finally will build the test track to verify the reliability requirements between the train and infrastructures

• Structural Engineering and Mechanics
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• 제82권1호
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• pp.1-16
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• 2022

This work elaborately investigates the influences of the guideway geometry parameters and track irregularity on the dynamic performances of the suspended monorail vehicle-guideway system (SMVGS). Firstly, a spatial dynamic analysis model of the SMVGS is established by adopting ANSYS parameter design language. Then, the dynamic interaction between a vehicle with maximum design load and guideway is investigated by numerical simulation and field tests, revealing the vehicle-guideway dynamic features. Subsequently, the influences of the guideway geometry parameters and track irregularity on the dynamic performances of the SMVGS are analyzed and discussed in detail, and the reasonable ranges of several key geometry parameters of the guideway are also obtained. Results show that the vehicle-guideway dynamic responses change nonlinearly with an increase of the guideway span, and especially the guideway dynamic performances can be effectively improved by reducing the guideway span; based on a comprehensive consideration of all performance indices of the SMVGS, the deflection-span ratio of the suspended monorail guideway is finally recommended to be 1/1054~1/868. The train load could cause a large bending deformation of the pier, which would intensify the car-body lateral displacement and decrease the vehicle riding comfort; to well limit the bending deformation of the pier, its cross-section dimension is suggested to be more than 0.8 m×0.8 m. The addition of the track irregularity amplitude has small influences on the displacements and stress of the guideway; however, it would significantly increase the vehicle-guideway vibrations and rate of load reduction of the driving tyre.

• 한국항공우주학회지
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• 제40권1호
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• pp.23-34
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• 2012

우주 발사체는 치밀한 비행 계획에 따라 사전에 결정된 경로를 비행하도록 설계된다. 그러나 비정상으로 추력이 종료되거나 계획된 비행경로를 이탈한 경우, 또는 자유 낙하 중인 대기권 재진입 발사체에 대한 추적 과정에서 추적 센서의 측정이 불가하게 된 경우 등에는 별도의 추적 장비를 이용한 추적 또는 신속한 낙하지점 추정이 필요하다. 본 논문에서는 클러터 환경에서 무추력 탄도 비행 중인 발사체에 대한 위치 정보를 획득하고 트랙을 생성 및 유지하기 위하여 Integrated Track Splitting(ITS) 알고리듬과 Extended Kalman Filter(EKF)를 결합한 ITS-EKF 알고리듬 적용을 제안한다. 따라서 대기권 재진입 발사체에 대하여 ITS-EKF 알고리듬을 적용한 시뮬레이션을 통해 추적 성능 확인 및 지상 낙하지점을 추정한다. ITS-EKF 알고리듬 적용 결과의 적절성을 확인하기 위하여 ITS와 Particle Filter를 결합한 ITS-PF 알고리듬을 적용하여 구한 추적 성능 및 낙하지점 분포 결과와 비교하여 제시된 알고리듬이 효과적인 실시간 On-line 낙하지점 추정에 사용이 가능함을 확인한다.

• 한국안전학회지
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• 제33권2호
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• pp.145-151
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• 2018

In this study, the track-bridge interaction analysis was performed using an analytical model considering the track structure, thereby taking into account the linear conditions (R=650 m, cant variation $160{\pm}60mm$) and the dynamic characteristics of the bridge. As a result of the study, the allowable speed on the example bridge considered was calculated at 200 km/h based on vertical deflection, vertical acceleration, and irregularity in longitudinal level, but was also evaluated at 170km/h based on the coefficient of derailment, wheel load reduction, and lateral displacement of the rail head. It is considered desirable to set the speed 170km/h to the speed limit in order to secure the safety of both the bridge and the track. It is judged that there will be no problems with ensuring rail protection and train stability in the speed band.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.948-954
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• 2004

이 연구의 목적은 호남선과 경부선의 기존선 전철화 선로의 곡선부에서 G7 개발차량과 KTX 차량의 속도를 증가해서 주행했을 경우 궤도구조의 성능평가와 주행안전성를 측정 분석한 것이다. 구조안전성과 주행안정성 평가를 위해서 측정기준으로 정립하였으며 계측망도를 구성하여 현장 계측을 수행하였다. 윤중, 횡압과 레일수직, 수평변위, 침목수직변위, 레일응력을 측정하였으며 이 결과를 토대로 궤도구조의 부담력과 열차 주행안정성을 평가하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.780-785
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• 2003

Maintaining track tension in tracked vehicles minimizes the excessive load on the tracks and prevents the peal-off of tracks from the road-wheel, and adequately guarantees the stable and improved driving of the tracked vehicles. However, the track tension cannot be easily measured due to the limitation in the sensor technology, harsh environment, etc. In this study, the track tension is estimated in real-time from the measurable signals of tracked vehicles and controlled based on a fuzzy logic controller. The proposed control system is implemented on tracked vehicles and its performance is evaluated under various driving conditions.

• International Journal of Railway
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• 제3권4호
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• pp.126-133
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• 2010

The thermal buckling analysis of curved continuous welded rail (CWR) is studied for the lateral buckling prevention. This study includes a thermal buckling theory which accounts for both thermal and vehicle loading effects in the evaluation of track stability. The parameters include rail size, track lateral resistance, track longitudinal and torsional stiffnesses, initial misalignment amplitude and wavelength, track curvature, tie-ballast friction coefficient and truck center spacing. Parametric studies are performed to evaluate the effects of the individual parameters on the upper and lower critical buckling temperatures. The results show that the upper critical buckling temperature is highly affected by the uplift due to vehicle loads. This study provides a guideline for the improvement of stability for dynamic buckling in curved CWR track.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.807-813
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• 2015

교량상의 장대레일은 궤도-교량상호작용에 의해 토노반상의 장대레일에 비해 복잡한 거동을 보인다. 궤도-교량 상호작용에 영향을 미치는 요인은 온도변화와 차량하중이다. 국내 철도설계지침 KR C-08080에서는 해석 시 사용하는 물성치, 모델링 방법, 하중 및 하중 조합 방법 등에 대하여 제시하고 있다. 2014년에 KR C-08080에서 제시된 차량하중이 변경되었다. 본 연구에서는 변경된 차량하중의 영향을 평가하기 위하여 22개 교량에 대한 궤도-교량 상호작용 유한요소 해석을 수행하였다.