• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 춘계학술대회논문집
• /
• pp.393-398
• /
• 2002

Rubber isolator has properties that can adjust easily stiffness and can be formed various shape. Also, it has high damping and is effective about structure-borne noise at high frequency range, So, rubber mount has widely used to isolate vibration at industrial equipment and construction field. However, rubber material is nonlinear and require enough consideration about shape factor whenever it is designed. The purpose of this paper is to develop conical rubber mount using compression and shear elasticity. The first, the dimension of mount is calculated by theoretical analysis considering design condition and static characteristics have been analyzed by FEM method. In addition, the fatigue test of rubber mount is performed to get reliability for product life and dynamic stiffness test is executed to get dynamic magnification factor. Finally, transmissibility test of vibration isolator has been carried out to suggest normal quantity data about vibration isolation.

• 한국정밀공학회지
• /
• 제17권12호
• /
• pp.101-106
• /
• 2000

As the rotational speed of optical disk drive is increasing nowadays, the reliability to vibration and shock becomes more important. For this, various of rubber vibration isolators are being developed by varying the shape and hardness. But it is difficult for the hardness of common used rubber to be lowered below Duro 30 degrees, and because of the shape complexity of rubber vibration isolator there are difficulties of analysis. Microcellular foamed vibration isolator has various cell densities and cell sizes, so it can vary the stiffness and damping coefficient. In addition, its hardness can be lowered below Duro 30 degrees. Axiomatic Approach is very useful design method for designing new product or new process. Axiomatic Approach's character is scientific and analytical method. In this paper, developing process of microcellular foamed vibration isolator for DVD is presented with Axiomatic Approach.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2002년도 춘계 학술발표회 논문집
• /
• pp.409-416
• /
• 2002

기존의 면진 기술을 일반건물에 적용하기 위해서는 낮은 가격과 낮은 무게로 면진 베어링이 제작 및 공급되어야 한다. 이에 본 논문에서는 일반건물에 면진 기술을 적용하기 위한 방법으로 기존의 적층고무 면진 베어링에 철판을 대체하여 섬유로 보강하고, 고무와 섬유의 층으로 구성된 벨트 타입의 면진 베어링을 제안하였다. 또한 제안한 섬유보강 면진 베어링을 설계 및 제작하여 수직실험과 수평실험을 수행하여 그 성능을 검증하였다. 따라서, 스트립형의 면진 베어링이 제작가능하며 일반건물의 필요한 크기로 절단이 가능함을 보였다. 또한 수평 실험 수직 실험을 통해서 기존의 적층고무 면진 베어링을 대체하여 사용할 수 있는 결과를 보였다. 이와 같은 결과를 통해서 일반건물에 낮은 무게와 낮은 가격의 면진 베어링을 공급할 수 있음을 보였다. 이 연구결과로 인해 스트립형의 섬유보강 면진 베어링이 저가건물에 널리 사용될 수 있을 것으로 기대된다.

• 한국지진공학회논문집
• /
• 제6권6호
• /
• pp.1-6
• /
• 2002

기존의 면진 기술을 일반건물에 적용하기 위해서는 낮은 가격과 낮은 무게로 면진 탄성받침 이 제작 및 공급되어야 할 필요가 있다. 이에 본 논문에서는 일반건물에 면진 기술을 적용하기 위한 방법으로 기존의 적층고무 면진 탄성받침에 철판을 대체하여 섬유로 보강하고, 고무와 섬유의 층으로 구성된 스트립형의 면진 탄성받침을 제안하였다. 또한 제안한 섬유보강 면진 탄성받침을 설계 및 제작하여 수직실험과 수평실험을 수행하여 그 성능을 검증하였다. 따라서, 스트립형의 면진 탄성받침이 제작가능하며, 필요한 크기로 절단이 가능함을 보였다. 또한 수평 실험 수직 실험을 통하여 기존의 적층고무 면진 탄성받침을 대체하여 사용할 수 있음을 보였다. 이 연구결과로 인해 스트립형의 섬유보강 면진 탄성받침이 저가건물에 널리 사용될 수 있을 것으로 기대된다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.376-379
• /
• 2006

Reaction Wheel Assembly (RWA) is one of the major disturbance sources that have influence upon the Line of Sight (LOS) of payload. A micro-vibration induced by RWA is propagated through the satellite structure and decrease the LOS stability performance of payload. This effect shall be analyzed through the jitter analysis. If a requirement or specification of payload jitter level is found to be not satisfied according to the jitter analysis campaign, some modification or redesign should be done on the satellite structure or a couple of isolator should be attached on the RWA interface in order to reduce the transmitted vibration level of RWA. The purpose of ???RWA isolator test? is to roughly evaluate the performance of vibration suppression level with a passive RWA isolator made of rubber. For this test, actual RWA is used as a vibration source and a couple of cube-shaped rubber mount designed for satellite is used as a passive isolator. There may be several considerations in order to accommodate RWA isolator to spacecraft such as not only vibration reduction performance but also thermal conduction problem, mechanical size, RWA alignment problem, etc. But in this report the feasibility of RWA isolator is analyzed only in a vibration suppression point of view. As a result, high frequency vibration of RWA above 50Hz is perfectly attenuated with isolators, however, first harmonic components below 50Hz became larger due to the additional low frequency resonance modes of roll, pitch, yaw rigid body motion of RWA+bracket.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.350-355
• /
• 2008

A Rubber mount is widely used for mechanical parts or engineering materials. Especially, it plays an important role in reducing mechanical vibration due to cyclic loading. But, rubber mount is damaged due to the cyclic loading and resonance. Therefore, it is necessary to investigate evaluation of fatigue life considering vibration characteristics for rubber. In this study, a vibration fatigue analysis was performed and based on Power Spectral Density(PSD) and the stress-life curve and a result of frequency response analysis in the finite element method. The measured load history in experiment was transformed to PSD curve. The stress-life curve was obtained by nonlinear static analysis and fatigue test. In addition, frequency response analysis was conducted for mechanical part. In order to evaluate fatigue life of rubber mount, vibration fatigue test was conducted at the constant acceleration-level as well. Fatigue life was determined when the load capacity is reduced to 60% of its initial value. As a result, predicted fatigue life of rubber mount agreed fairly well with the experimental fatigue life.

• Structural Engineering and Mechanics
• /
• 제29권3호
• /
• pp.259-278
• /
• 2008

This paper presents a nonlinear finite element procedure accounting for the effects of geometric as well as material nonlinearities for reinforced concrete bridge piers supported by laminated rubber bearings. Reinforced concrete bridge piers supported by laminated rubber bearings and carrying a cyclic load were analyzed by using a special purpose, nonlinear finite element program, RCAHEST. For reinforced concrete, the proposed robust nonlinear material model captures the salient response characteristics of the bridge piers under cyclic loading conditions and addresses with the influence of geometric nonlinearity on post-peak response of the bridge piers by transformations between local and global systems. Seismic isolator element to predict the behaviors of laminated rubber bearings is also developed. The seismic performance of reinforced concrete bridge piers supported by laminated rubber bearings is assessed analytically. The results show good correlation between the experimental findings and numerical predictions, and demonstrate the reliability and robustness of the proposed analytical model. Additionally, the studies and discussions presented in this investigation provide an insight into the key behavioral aspects of reinforced concrete bridge piers supported by laminated rubber bearings.

• Structural Engineering and Mechanics
• /
• 제67권1호
• /
• pp.69-78
• /
• 2018

The study presented herein focused on the change in hysteretic force-deformation behavior of lead rubber bearings (LRBs). The material model used to idealize response of LRBs under cyclic motion is capable of representing the gradual attrition in strength of isolator unit on account of lead core heating. To identify the effect of loading history on the hysteretic response of LRBs, a typical isolator unit is subjected to cyclic motions with different velocity, amplitude and number of cycles. Furthermore, performance of an LRB isolated single degree of freedom system is studied under different seismic input levels. Finally, the significance of lead core heating effect on LRBs is discussed by considering the current design approach for base isolated structures. Results of this study show that the response of an LRB is governed strongly by the amplitude and number of cycles of the motion and the considered seismicity level.

• 소음진동
• /
• 제7권5호
• /
• pp.789-796
• /
• 1997

In this study a conventional rubber mount and a new form of base isolator made of steel spring coated with natural and articial rubber were manufactured and tested on a shaking table to investigate the capacity of reducing the vertical vibration of a building induced by subway train. The model structure used in the test is a 1/4 scaled steel structure, and a white noise input and train vibration records were used to check the effectiveness of the isolators. According to the results all three types of isolators turned out to perform effectively in reducing the acceleration and the natural rubber-coated one is ranked best among the isolators. However the vertical displacement of the model is increased due to the instolation of the bearings, and the safty against the lateral load induced by earthquake ground motion should be provided to be able to apply the system to the real buildings.

• Earthquakes and Structures
• /
• 제16권5호
• /
• pp.523-532
• /
• 2019

Different types of gas reservoir such as Liquid Natural Gas (LNG) are among the strategic infrastructures, and have great importance for any government or their private owners. To keep the tank and its contents safe during earthquakes especially if the contents are of hazardous or flammable materials; using seismic protection systems such as base isolator can be considered as an effective solution. However, the major deficiency of this system can be the large deformation in the isolation level which may lead to the failure of bearing system. In this paper, as a solution, the efficacy of an optimally designed combined vibration control system, the combined laminated rubber isolator and rotational friction damper, is investigated to evaluate the enhancement of an existing metal tank response under both far- and near-field earthquakes. Responses like impulsive and convective accelerations, base shear, and sloshing height are studied herein. The probabilistic framework is used to consider the uncertainties in the structural modeling, as well as record-to-record variability. Due to the high calculation cost of probabilistic methods, a simplified structural model is used. By using the Mont-Carlo simulation approach, it is revealed that this combined isolation system is a highly reliable system which provides considerable enhancement in the performance of reservoir, not only leads to the reduction of probability of catastrophic failure of the tank but also decrease the reservoir damage during the earthquake. Moreover, the relative displacement of the isolation level is controlled very well by this combined system.