• 한국철도학회논문집
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• 제15권6호
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• pp.543-549
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• 2012

본 연구는 차세대 분산형 고속전철 시제차량(HEMU-430X)의 후미진동저감에 관한것이다. VAMPIRE 해석을 통한 주행거동 관찰에서 HEMU-430X는 전두부 유선형 형상유지를 위하여 설치된 한방향 요댐퍼 때문에 후미차량에서 횡방향 진동이 예상되었으며, 430km/h에서 기준치를 초과하는 경우가 있었다. 이 후미진동을 감소시키기 위하여 차륜답면 형상변경, 횡댐퍼 댐핑계수조정, 요댐퍼 계수조정 등 다양한 방법을 시도하였으나 후미진동이 없어지지 않았다. 최종적으로 요댐퍼를 양방향으로 바꾸었을 때 횡방향 진동이 사라졌다. 실제 시운전에서는 150km/h로 주행하였을 때 횡방향 후미진동이 나타났으며, 요댐퍼를 양방향으로 바꾸어 300km/h 주행 시에도 후미진동이 나타나지 않았다. 추후 430km/h까지 최고속도시험을 수행할 예정인데 높은 속도에서 후미진동이 다시 발생한다면 본 연구에서 제시한 차륜답면 형상변화, 횡댐퍼 계수 조정 등의 방법을 이용해서 진동을 저감시킬 수 있을 것이다.

• 한국지반신소재학회논문집
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• 제22권2호
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• pp.35-45
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• 2023

도심지 개발사업에 따라 철도구조물 인근에서 지반굴착을 위한 가시설 구조물을 시공하는 사례가 증가하고 있다. 또한 가시설 구조물 설치 후 신축한 대형건물에 주거하는 사람들로부터 열차진동에 대한 민원도 증가하고 있다. 이와 같은 문제를 해결하기 위해 건물의 설계단계부터 열차진동을 저감하기 위한 방법이 고려되고, 건물 신축 시 구조물에 방진시스템이 설치된다. 그러나 구조물 설계단계에서 수립되는 방진대책은 특정 지역에 대한 현장계측 또는 동적 수치해석의 결과를 통해 결정할 수 있고, 객관적인 관련 연구 자료가 부족하여 수립한 방진대책의 적정성을 평가하는데 한계가 있다. 이에 본 연구에서는 방진대책의 수립을 위한 객관적인 기초자료 제공을 목적으로 수치해석을 통해 철도구조물의 심도, 철도와 가시설 구조물의 이격거리 및 지반조건을 달리하여 시속 80km/h인 운행열차를 대상으로 동적 수치해석을 수행하였다. 연구결과, 시속 80km/h인 운행열차의 영향범위는 가시설 벽체가 설치된 조건의 경우 철도구조물로부터 이격거리 4.5D이내인 것으로 나타났다.

• 한국정밀공학회지
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• 제28권6호
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• pp.651-656
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• 2011

Although prosthetic training was received, most of amputees mainly depend on visual feedback to use prostheses, not on cutaneous and proprioceptive sensibility. Our objective of this study was to determine if there are changes in the somatosensory sensibility of amputees compared to non-amputees using multi-channel vibration stimulation system. One transradial amputees and ten non-amputees were involved. To investigate changes of residual somatosensory sensibility at stump, we set up custom-made vibration stimulation system including eight actuators (4 medial and 4 lateral) and GUI-based acquisition system. The results showed that there was similar pattern of subjective response at most of channels among group as stimulation increases. However, amputees' subjective response at channel 8 for 238Hz vibration was more sensitive than that of healthy persons. With respect to channels, response at channel 4 (medial) corresponding region to flexor carpi ulnaris for transradial amputees was most sensitive than other channels. In addition, sensitivity of four medial channels was on average about 0.5 scale than that of four lateral channels. Somatosensory sensibility was amputee, women, and men in sensibility order.

• 대한의용생체공학회:의공학회지
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• 제30권3호
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• pp.247-254
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• 2009

We studied the postural response induced by plantar sole vibration with various frequencies(20, 60, 100Hz) and vibration zone(the anterior and posterior foot zone) of both soles during standing. Eight healthy young adults were exposed to 15s periods of plantar sole vibration while blindfolded. Body sway(COM, center of mass), the angle of neck, trunk, hip, knee, ankle and EMG of four lower limb muscles(tibialis anterior, lateral and medial gastrocnemial, soleus muscle) were recorded during 15s plantar sole vibration using 3D motion analysis system. Simulating each zone separately resulted in spatially oriented body tilts; oppositely directed backward and forward, respectively, the amplitude of which was proportional to the vibration frequency. EMG activity of lower limb muscles also varied according to the direction of the vibration zone and linearly according to the frequency. These findings led us to consider the plantar sole vibration as useful method of postural balance control and adjustment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.218-219
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• 2009

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.749-754
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• 2007

In this paper, the vibration of a rotating shaft with a thin rigid disk is considered. It is assumed that the shaft has uniform, circular cross-section. Based on the Timoshenko-beam theory, the transverse displacements and slops in two lateral directions, the axial displacement, and the torsional deformation are considered. The spectral element method is used for the vibration analysis of the rotating shaft with a thin rigid disk, which is modeled by two shaft elements and a thin rigid disk element.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.810-813
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• 2004

A study on the dynamic response of single-storey steel frames equipped with a rotational friction damper is presented. Extensive testing was carried out for assessing the friction pad material, damper unit performance and foaled model frame response to lateral harmonics excitation. Numerical simulations based on non-linear time history analysis were used to evaluate the seismic behaviour of steel frames with rotational frictional damper. It Is demonstrated that using discrete friction dampers of proper parameters to link steel frame can reduce dynamic response significantly.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 춘계학술발표대회 논문집
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• pp.57.1-60
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• 1999

This paper presents the effects of partial dampers on the lateral vibration of beams. Both shear and normal stresses in the viscoelastic layer were studied. Analytical results were compared with those obtained by a finite element method. Effects of the size of partial dampers on the system loss factors and resonant frequencies were discussed.

• 소음진동
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• 제9권5호
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• pp.928-935
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• 1999

Vertical pumps are widely used owing to the fact that they occupy small floor space. In this type of pumps, however, the vibrational problems are very important, since, in many cases, they have less stiffness in comparison with lateral pumps. This study presents a simple solution method for calculating the natural frequencies and modes of vertical pumps. In this study, a mode of a vertical pump was developed and the nondimensional parameters for the vibrational characteristics of it were determined. Added mass was calculated for the effects of water and the transfer matrix method was used.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.43-51
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• 2004

As the slenderness ratio of a high-rise building increases, the lateral load resisting system for the building is more often determined by serviceability design criteria. In serviceability design, the maximum drift and the level of vibration are controlled not to exceed the design criteria. Even though many drift method have been developed in various forms, no practical design method for wind induced vibration has been developed so far. Structural engineers rely upon heuristic or experience in designing wind induced vibration. Development of practical design method for wind induced vibration is required. Generally, wind induced acceleration responses are depending on several variables such as the weight density of a building, damping ratio, the natural period, and etc.. All parameters except the natural period or frequency are usually out of reach for structural engineers, then the wind acceleration response may be proportioned to the natural period. Therefore, in this paper, a wind induced vibration design method based on frequency control technique for high-rise is proposed. The method is applied to vibration design of a 25-story office building for performance evaluation.