• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.126-131
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• 2003

The acceptance test of KTX has been performed in Korea. During the test, lateral vibration of carbody over the accepted value called sway was found. KTX has 20 car trainset formation whose trailer cars are linked by articulate bogies. So this study is performed to see the effects of long trainset formation on vehicle dynamics and the train stability by 20 car vehicle model. Firstly the reliable vehicle model which shows well the tendencies appeared in the tests on the high speed test line is required to find the cause of lateral vibration and the countermeasure. Vehicle model was made .for the. analysis with VAMPIRE. The analysis results show that secondary air spring lateral stiffness is the most significant parameter to cause carbody lateral vibration. Mode analysis results show that the least damped mode shape is similar to the vibration pattern shown in the tests that the amplitude of the motion increases along the train set and decreases in the tail part. For the case of short train formation with 7 or 10cars, sway does not happen. But in the case of longer train formation with 16 or 20 cars, sway was found.

• 전산구조공학
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• 제8권1호
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• pp.95-106
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• 1995

지하철의 운행에 의한 소음과 진동은 운행로 주위의 주민을 괴롭히는 중요한 요소의 하나이다. 일반적인 건물의 진동은 횡방향의 진동을 많이 고려하고 있으나 지하철의 운행에 의한 건물의 진동은 수직방향의 진동을 주요하게 다루어야 한다. 수직방향의 진동을 고려하기 위한 구조물은 보의 진동이 고려된 모델이어야 한다. 따라서 구조물의 수평방향 진동을 고려하기 위하여 사용된 모델은 수직방향의 진동을 고려하기 위한 모델과 같이 사용될 수 없다. 건물의 수직진동을 고려한 해석을 수행하기 위해서는 보의 관성력을 충분히 고려할 수 있는 모델이 사용되어야 한다. 본 논문에서는 지하철의 운행에 의한 구조물의 수직방향진동을 고려하기 위한 구조물의 해석 모델기법에 대하여 연구한 결과 기둥의 경우 하나이상 보의 경우 두개 이상의 요소로 나누어 해석하는 것이 바람직한 것으로 나타났다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.984-987
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• 2003

This paper discusses the lateral vibration of a bar which has its tip free. The uniform bar has a solution by summation of some simple exponential functions. But if its shape is not uniform, its solution could be by Bessel's function, or mathematical solution could not be existed. Even if the solution of Bessel's function exists. as Bessel function is a series function, we must get the solution by numerical method, Hereof the author proposes the solution of the matrix method by Ritz's method, and proposes a new deflection shape

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.435-440
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• 2001

In this study, torsional and lateral vibrations of a gear box transmission system were analyzed theoretically using some mathematical models and examined to determine the causes of its excessive vibrations. As the results, it was found there exist possibility of resonance between gear mesh frequencies and lateral vibration mode of the transmission shaft during the third shifting mode operation. In order to avoid this resonance, we proposed changing the arrangement of gears on the transmission shaft. The measured vibration levels of the improved gear box were dramatically reduced. These results may be helpful to design a machine tool gear box with low noise and vibration.

• Wind and Structures
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• 제15권3호
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• pp.263-283
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• 2012

This paper presents a framework of nonlinear dynamic analysis of a low-speed moving maglev (magnetically levitated) vehicle subjected to cross winds and controlled using a clipped-LQR actuator with time delay compensation. A four degrees-of-freedom (4-DOFs) maglev-vehicle equipped with an onboard PID (Proportional-Integral-Derivative) controller traveling over guideway girders was developed to regulate the electric current and control voltage. With this maglev-vehicle/guideway model, dynamic interaction analysis of a low-speed maglev vehicle with guideway girders was conducted using an iterative approach. Considering the time-delay issue of unsynchronized tuning forces in control process, a clipped-LQR actuator with time-delay compensation is developed to improve control effectiveness of lateral vibration of the running maglev vehicle in cross winds. Numerical simulations demonstrate that although the lateral response of the maglev vehicle moving in cross winds would be amplified significantly, the present clipped-LQR controller exhibits its control performance in suppressing the lateral vibration of the vehicle.

• 한국정밀공학회지
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• 제28권8호
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• pp.959-965
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• 2011

This paper presents the dynamic modeling and vibration suppression methods for axially deploying beams subjected to gravity. A modal modeling method is employed to develop the lateral vibration model for axially deploying beams. Simulation is made to validate the proposed model as well as to investigate the dynamics of axially deploying beams. This paper rigorously investigates the gravity effect as a source of vibration for axially deploying beams. In order to suppress lateral vibration for deploying beams, the moving speed command is modified by using the input shaping method, Experiments are also performed to prove the proposed vibration suppression method. The simulations and experiments show that the proposed modeling and input shaping methods are effective for the dynamic analysis and vibration suppression of axially deploying beams subjected to gravity.

• 전기학회논문지
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• 제58권2호
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• pp.270-277
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• 2009

This paper deals with a vibration and efficiency characteristics of Permanent Magnet Linear Synchronous Motor according to the PM arrangement. The generated force such as the thrust, detent force, normal force and lateral force are compared with analysis values and experimental ones. Furthermore characteristics of vibration and efficiency are estimated by experiments.

• 대한기계학회논문집A
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• 제36권11호
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• pp.1447-1453
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• 2012

도시형 자기부상열차는 U 자형 전자석만을 사용하여 부상공극을 일정하게 유지하며 주행한다. U자형 전자석은 그 형상 특성으로 인하여 전자석 위치에 따라 안내력을 동시에 갖기 때문에 능동적 횡공극 제어가 없이도 차량을 레일에 따라 안내할 수 있는 장점을 갖는다. 그러나 횡공극을 제어하기 않기 때문에 횡진동이 증가하여 승차감 및 주행안정성에 악영향을 미칠 수 있다. 본 논문에서는 능동제어가 없이도 횡진동을 저감시키기 위한 방법으로 횡댐퍼 적용 효과에 대한 분석이 이루어진다. 이를 위하여 자기부상열차의 횡방향 고유진동특성을 우선 해석하고, 횡방향 댐퍼를 설치했을 때의 진동저감 효과 분석이 이루어진다. 정확한 횡진동 예측을 위하여 자기부상열차의 3 차원 다물체 동역학 모델을 사용하였다. 본 논문의 결과를 통해서 자기부상열차의 횡진동 저감을 위한 횡댐퍼 채택 제안에 활용하고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.301-306
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• 2016

추진축계 횡진동은 축계배치계산과 함께 설계단계에서 충분한 검토가 이루어져야 한다. 축계 강제 횡진동 문제는 아직 명쾌한 해석방법이 제시되지 못하고 있으며 선급, 국제규격 등에서 대략적으로 프로펠러 날개차수 고유 진동수가 엔진정격회전수의 ${\pm}20%$이내에 들지 못하게 하고 있다. 축계배치관점에서는 축계 지지베어링 중심간 사이의 거리가 멀수록 좋으나 횡진동관점에서는 파장이 길어지고 고유진동수는 낮아져 공진이 발생할 수 있는 요인이 되어 검토시 주의가 요구되므로 계산결과를 실측으로 검증하는 것이 바람직하다. 본 연구에서는 최근 친환경 고효율 선박으로 등장한 5만 DWT급 석유화학제품운반선을 대상으로 횡진동 이론적 분석 및 스트레인 게이지 계측자료 분석을 수행하고 이를 통해 횡진동이 추진축계에 미치는 영향을 검토하였다.

• Structural Engineering and Mechanics
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• 제55권5호
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• pp.1015-1035
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• 2015

A three-dimensional (3D) numerical analysis for the train-bridge interaction (TBI) system is actively developed in this study in order to investigate the vibration characteristics of rigid-frame reinforced concrete (RC) viaducts in both vertical and lateral directions respectively induced by running high-speed trains. An analytical model of the TBI system is established, in which the high-speed train is described by multi-DOFs vibration system and the rigid-frame RC viaduct is modeled with 3D beam elements. The simulated track irregularities are taken as system excitations. The numerical analytical algorithm is established based on the coupled vibration equations of the TBI system and verified through the detailed comparative study between the computation and testing. The vibration responses of the viaducts such as accelerations, displacements, reaction forces of pier bottoms as well as their amplitudes with train speeds are calculated in detail for both vertical and lateral directions, respectively. The frequency characteristics are further clarified through Fourier spectral analysis and 1/3 octave band spectral analysis. This study is intended to provide not only a simulation approach and evaluation tool for the train-induced vibrations upon the rigid-frame RC viaducts, but also instructive information on the vibration mitigation of the high-speed railway.