• 한국소음진동공학회논문집
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• 제20권4호
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• pp.373-380
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• 2010

An interest is increased of environment and energy so, importance on railroad high energy efficiency is magnified. And after Gyeong-bu High speed rail is completed, share rate freight transportation of railroad is expected to be gradually increased due to expand investment for railroad and operate mainly freight transportation on convention line. Therefore a research on DMT freight cars is necessary under like this situation. In paper, we developed analysis model for DMT freight car and DMT freight was analyzed numerically using VI-Rail in each condition of railway having different curve and carried out vibration analysis on curving using developed analysis model. And we carried out test on driving stability follow changing curve radius then measure against UIC code 518.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.806-811
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• 2004

Currently, in the design criteria for the high speed railway bridges, the maximum distance between bridge expansion joint is limited to 80m using a continuous welded mil, in order to limit the additional stress in the rail due to the rail-bridge interaction. In the past study on the resonance effect of HSR train, it is known that the reduction of resonance and dynamic responses of bridge deck occurs at the specific expansion length of 28.05m and 46.75m. In this study, the stability of track structure on the HSR bridges with expansion length of 90m has checked by finite element method. And the track behavior including mil stresses and relative displacements are compared to the current state of track structures on the bridge system with 80m long expansion length.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2487-2492
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• 2011

At high rail temperature above the neutral temperature, high compressive axial stresses will occur in the rails. High thermal axial force and vehicle loads cause the track to shift in a lateral direction and the formation of track geometry imperfections (track irregularity). When the thermal stress level and track irregularity with vehicle load reach a critical value, the track loses stability. In many studies, the stability of CWR tracks is analyzed. However these studies are only considered in temperature load. The main objective of this investigation was to estimate a new, comprehensive, realistic, the stability of CWR tracks considering wheel load. The ballast resistance is changed by wheel load. When the wheel load is applied, rails and ties are moved upward or downward. In this case the friction between ties and ballasts is decreased or increased. In this study the change of the ballast resistance of each tie was applied to the nonlinear analysis of CWR tracks.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.218-221
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• 2004

This Research is to test the running stability of the developed bogie with 350km/h of which conventional speed is faster than Korea TGV 300Km/h. The running stability test has been executed in status of a car with the developed bogie on the roller rigger to adjust similar to the actual condition. And the test has been done in the two rail conditions, i.e. excitation and non-excitation, respectively. Running speed of bogie increased by the roller step by step. In consequence, the developed bogie in the non-excitation has run without any unstable point for 400kn0h. Vibration characteristics of carbody also was within the value specified on the UIC 518.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.839-844
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• 2002

This research aims to test the running stability of the developed bogie with maximum operating speed of 350km/h, which of Korea TGV was 300km/h. The running stability test has been executed in status of a dummy car with one developed bogie and one dummy bogie on the roller rig to embody similar operation condition. The test has been done in the two rail conditions, i.e. excitation and non-excitation, respectively. Running speed has been increased by the roller step by step. In consequence, the developed bogie was proven to be able to run upto 400 Km/h without any unstable point in the non-excitation. Vibration characteristics of carbody also was within the value specified on the UIC 515.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.426-436
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• 2006

The use of the CWR track has increased consistently in the worldwide. Because the use of CWR track not only reduces the track maintenance cost, noise and vibration, but increases the life cycle of track components. Therefore, to increase train speed, improve riding condition and secure running stability, the necessity of study on making CWR is increasing. This study includes the development of a thermal buckling theory in the evaluation of curved track stability. The lateral stability of curved CWR is studied for track buckling prevention through the parameter studies. It studied the lateral buckling of the curved CWR track on the 3-D nonlinear analysis. The parameters include rail size, cant, track curvature.

• 한국항해항만학회지
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• 제30권8호
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• pp.685-690
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• 2006

컨테이너 터미널에서 컨테이너의 양 하역 작업 시 컨테이너 크레인을 정위치에 고정시키고, 돌풍으로 인해 컨테이너 크레인이 레일방향으로 미끄러지는 것을 방지하는 장치가 레일클램프이다. 쐐기형 레일클램프는 초기에는 작은 압착력으로 레일을 압착하다가 풍속이 증가하면 쐐기작용에 의해 압착력이 증가하는 방식을 취함으로서 구조적으로 안정성과 내구성이 높은 장점을 가지고 있다. 본연구에서는 레일클램프의 주요부인 조에 대해 형상최적설계를 수행하였다. 본 논문에서는 솔리드 요소로 유한요소 모델링된 조(jaw)의 경량화 설계를 위하여 강도를 고려하였다. 설계변수로는 조의 측면부의 두께, 조의 중간부의 롤러지지부의 두께, 조의 하단부의 롤러지지부의 두께, 조의 곡면부의 위치로 설정하였다. 본 연구에서는 상용프래그램인 ANSYS WORKBENCH의 최적화 기능을 이용하였다.

• Smart Structures and Systems
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• 제23권6호
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• pp.641-651
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• 2019

The stochastic stability control of the parameter-excited vibration of an inclined stay cable with multiple modes coupling under random and periodic combined support disturbances is studied by using the direct eigenvalue analysis approach based on the response moment stability, Floquet theorem, Fourier series and matrix eigenvalue analysis. The differential equation with time-varying parameters for the transverse vibration of the inclined cable with control under random and deterministic support disturbances is derived and converted into the randomly and deterministically parameter-excited multi-degree-of-freedom vibration equations. As the stochastic stability of the parameter-excited vibration is mainly determined by the characteristics of perturbation moment, the differential equation with only deterministic parameters for the perturbation second moment is derived based on the $It{\hat{o}}$ stochastic differential rule. The stochastically and deterministically parameter-excited vibration stability is then determined by the deterministic parameter-varying response moment stability. Based on the Floquet theorem, expanding the periodic parameters of the perturbation moment equation and the periodic component of the characteristic perturbation moment expression into the Fourier series yields the eigenvalue equation which determines the perturbation moment behavior. Thus the stochastic stability of the parameter-excited cable vibration under the random and periodic combined support disturbances is determined directly by the matrix eigenvalues. The direct eigenvalue analysis approach is applicable to the stochastic stability of the control cable with multiple modes coupling under various periodic and/or random support disturbances. Numerical results illustrate that the multiple cable modes need to be considered for the stochastic stability of the parameter-excited cable vibration under the random and periodic support disturbances, and the increase of the control damping rather than control stiffness can greatly enhance the stochastic stability of the parameter-excited cable vibration including the frequency width increase of the periodic disturbance and the critical value increase of the random disturbance amplitude.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6977-6984
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• 2015

품질 향상을 위해 연속적인 소성 변형을 이용한 롤 포밍 공정에 피어싱, 벤딩, 트리밍 등 별도의 가공공정을 통합한 볼 슬라이드 레일의 멀티 롤 포밍 공정의 필요성이 대두되고 있다. 하지만 프레스기의 진동 및 소음은 이 공정에서 생산되는 슬라이드 레일의 품질 저하를 유발한다. 본 연구에서는 롤 포밍 유한요소 프로그램으로 최적 변형률을 고려하여 롤을 설계하였다. 그리고 멀티 공정의 정적 안정성을 예측하기 위해 구조해석 프로그램으로 프레스기에 대한 응력 및 변형량을 계산하였다. 또한 공진영역에서의 장치들의 운전을 회피하기 위해 Modal 해석을 통해 1, 2차 모드에서의 고유진동수를 계산하였다. 그 결과 공정의 동적 안정성 개선을 확인하기 위해 마이크로폰과 가속도계를 이용하여 기존 및 연구 공정들의 소음, 진동의 크기를 비교하였다. 그리고 기존 및 연구 공정으로 생산되어진 레일의 폭 치수와 표면거칠기를 측정하였다. 따라서 해석 및 실험적 연구를 통해 멀티 롤 포밍 공정이 안정하다는 것을 알 수 있었다.

• 한국안전학회지
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• 제31권6호
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• pp.45-51
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• 2016

The purpose of this study is to investigate the influence of train-induced end rotation of simple supported track girder on the performance of a direct fixation track system (DFTS) in Yeongjong grand bridge. In this study, the influences of deflection of a DFTS and track girder on dynamic rail-track girder interaction forces for the track girder ends currently employed in airport express lines were assessed by performing field tests using actual vehicles running along the service lines. Therefore, the dynamic displacement of rail and track girder and the fastener stress on the center and ends sections of DFTS were measured for two different trains (AREX and KTX) running in Yeongjong grand bridge. A three-dimensional finite element analysis (FEA) model using the time-history function based on the design wheel load was used to predict the train-induced track and track girder displacement, and the FEA and field test results were compared. The analytical results reproduced the experimental results well within about 3-7% difference in the values. Therefore, the FEA model of DFTS on track girder is considered to provide sufficiently reliable FEA results in the investigation of the behavior of DFTS. Using the analytical and experimental results, the influence of train-induced end rotation of simple supported track girder on the interaction behavior of rail and track girder installed on a simple supported track girder ends, i.e., upward displacement of rail-track girder and the fastener stress, was investigated. It was found that the train-induced end rotation effect of track girder was not significantly affected by the upward displacement of rails and the fastener stresses of track girder ends. Further, the interaction behavior of rail and track girder were similar to or less than that of the general railway bridge deck ends, nevertheless the vertical displacement of track was higher than that of conventional DFTS on the general railway bridge. From the results, the dynamic responses of the DFTS on track girder ends were not significantly affected by the safety and stability of DFTS ends.