• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.48.4-48
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• 2002

1) A method to realize active vibration control using SAC and acceleration type sensor is proposed from the viewpoint of practical application. 2) The use of acceleration type sensor makes it easy to satisfy ASPR condition in applying SAC system and to implement sensor in practical mechanical system. 3) Results were confirmed through numerical simulation of 1 DOF vibration system.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.105-108
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• 2006

should be in This paper presents review on human comfort criteria in major codes and standards for tall buildings. In general, human comfort criteria of tall buildings have been used by magnitude of wind-induced acceleration response. Two different indexes in determination of the magnitude have been used: the peak value which occurs during a period of time and the rms value averaged over this same period. These distinctive acceleration indexes are discussed in detail and each criterium was reviewed and compared. The distinctions arisen because of the different wave forms, or acceleration signatures were addressed. It is described that which index of acceleration should be adopted in establishment of Korean human comfort criteria. In addition, some arguments from a technical standpoint that favor the use of each index are presented.

• 한국지반공학회지:지반
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• 제11권4호
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• pp.37-48
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• 1995

본 연구에서는 수직가속도를 일으키는 진동실험을 통하여 정규진동 및 무작위 진동시의 건조 사질토에 대한 동적거동을 분석하였다. 실험결과로부터 진동가속도와 상대밀도의 관계곡선을 제안하였으며, 여러가지 상재하중하에서의 거동특성을 규명하였다. 실험에는 완전건조된 사질토를 사용하였으며, 입경별로 4개의 시료로 나누고, 현장입경상태를 재현한 시료를 더하여 총 5개의 시료를 사용하였다. 정규진동실험의 경우, 진동진폭은 0.4mm~0.6mm로 유지하고 진동주파수를 3~40Hz 범위에서 변화시키면서 가속도에 따른 시료의 상대밀도 변화를 측정하였다. 무작위진동실험의 경우, 무작위파 발생기를 이용하여 무작위진동파와 10~50Hz 범위의 정규진동파가 조합된 합성파를 발생시키고, 가속도센서로 가속도를 측정하면서 상대밀도의 변화를 측정하였다. 본 연구결과, 수직가속도만으로 사질토를 94%~99%의 상대밀도까지 다질 수 있었으며, 최대 상대 밀도를 발생시키는 수직가속도는 시료가 최소 건조 단위 중량일 때의 간극비와 최대 건조 단위 중량일 때의 간극비 차이에 비례하는 것을 알 수 있었다. 또한, 상재하중을 가하지 않은 경우가 상재하중을 가한 경우보다 시료의 상대밀도변화가 크게 나타탔으며, 상재하중이 클수록 상 대밀도의 변화가 일어나는 가속도가 커짐을 알 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.256-260
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• 2013

The fan-shroud plays the important role in cooling down the engine heat by the forced convection. As the fan-shroud is made by injection molding, the unbalance of the fan blades is inevitable, and its low frequency characteristics makes it easy to excite the resonances of the environmental structures. So controlling its vibration, specially the dominant vibration source of unbalance vibration, is one of key factor to improve the sound and vibration quality of the modern vehicles. This paper introduces the plane balancing method, the most appropriate way of controlling the fan-shroud by generating the acceleration orbit measured from 2 accelerometers, and proves its balancing effect by the experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.985-990
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• 2003

With the rotational speed of the hard disk drive (HDD) increased, the low frequency structural vibration induced by the unbalance force gives rise to the structure home noise of the personal computer, and finally degrades the noise quality. As the unbalance of the hard disk drive is decided by the mechanical assembly allowance between clamping and platter disk, there is limit to control this unbalance by the improved assembly method. To improve the noise and vibration performance of PC, basically the unbalance of HDD needs to be measured absolutely and reduced during the stage of the disk assembly. This study introduces the HDD unbalance measurement methods of the absolute magnitude based on the mobility concept, and the unbalance location information with the acceleration orbit.

• 재활복지공학회논문지
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• 제11권2호
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• pp.133-141
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• 2017

하이브리드 음향센서 (hybrid acoustic sensor)는 음압 기반의 음향센서 (ECM)와 진동 기반의 가속도 센서(acceleration sensor)가 접목된 구조이다. 이는 음향센서의 저주파 대역 감도와 가속도 센서의 고주파 대역 감도를 결합하여 저주파에서 고주파 대역까지 광범위하게 음향을 포집할 수 있다. 본 논문에서는 하이브리드 음향센서에 사용되는 가속도 센서를 제안하였다. 가속도 센서는 음향신호에 의해 발생되는 고막의 진동을 포집한다. 제안된 가속도 센서의 사이즈는 고막의 해부학적 구조와 음향센서인 ECM의 규격을 고려하여 직경 3.2 mm로 결정하였다. 그리고 하이브리드 음향센서가 고감도 광대역 특성을 가지도록 하기 위해서는 가속도 센서의 공진 주파수는 3.5 kHz 부근에서 생성되는 것을 목표로 하였다. 가속도 센서를 구성하는 진동막은 수학적 모델과 유한요소 해석을 통하여 기하학적 구조를 도출하였다. 이를 바탕으로 화학적 식각공정을 이용하여 진동막을 제작하였다. 그리고 제작된 진동막의 주파수 특성을 확인하기 위하여 외력에 의한 진동 측정 실험을 수행하였고, 실험 결과 진동막의 기계적 공진은 3.4 kHz에서 발생되었다. 그러므로 제안한 가속도 센서는 하이브리드 음향센서에 유용하게 활용될 수 있을 것으로 판단된다.

• Journal of Biosystems Engineering
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• 제27권5호
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• pp.391-398
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• 2002

During handling unitized products, they are subjected to a variety of environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization of pallets has been resulted in a reduction of the shock hazards. This has caused an increasing interest in research focused on vibration caused dam age. Damage to the product by the vibration most often occurs when a product or a product component has a natural frequency that falls within the range of the forcing frequencies of the particular mode of transportation being used. Transportation vibration is also a major cause of fruit and vegetable quality loss due to mechanical damage. This study was conducted to determine the vibration characteristics of the corrugated fiberboard bones for packages of pears, and to investigate the degree of vibration injury of the pears in the boxes during the simulated transportation environment. The vibration tests were performed on an electrohydraulic vibration exciter. The input acceleration to exciter was fixed at 0.25 G for a single container resonance test and 0.5 G for the vertical stacked container over the frequency range from 3 to 100 Hz. Function generator (HP-33120A) was connected by wire to the vibration exciter for controlling the input acceleration at a continuous logarithmic sweep rate of 1.0 octave per min. The peak frequency and acceleration on the single box test were 22.02 Hz, 1.5425 G respectively, and these values on the vertical stacked boxes were observed from the bottom box 19.02, 18.14, 16.62 and 15.40 Hz and 2.2987, 3.7654. 5.6087, and 7.9582 G, respectively. The pear in the bottom box had a slightly higher damage level than the fruit packed in the other stacked boxes. It is desirable that the package and transportation system has to be so designed that 15∼20 Hz frequency will not occur during the transportation environment.

• 한국안전학회지
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• 제24권1호
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• pp.60-68
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• 2009

The aim of this paper is to evaluate the compatibility of anti-vibration gloves, to predict the attenuation of vibration with different types of anti-vibration gloves, to estimate the spectra of the ISO 10819 standard, and to present an oscillating spectrum adequate for vibrating tools. This paper use two ISO standards for the measurement and evaluation of hand-arm vibration. Some anti-vibration gloves can attenuate vibration, but all the anti-vibration gloves in this study do not satisfy the ISO 10819 requirements. In case of equal vibration types, the outside materials are effective in order of leather, fabrics and rubber-coating. Anti-vibration gloves manufactured in the United State satisfy ISO 10819 criteria using United State subjects, but do not satisfy ISO 10819 using Japanese subjects. M-spectrum acceleration exists below 10Hz and H-spectrum exists above 500Hz. Generally vibrating tools have the peak of Z-axis, but generation of vibration differ from each vibrating tools.

• 한국소음진동공학회논문집
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• 제21권8호
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• pp.733-740
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• 2011

This paper deals with the process to identify the transient exciting force generated from a rotary compressor. The compressor was assumed to be a rigid body. The equation of motion of a rigid compressor supported by three mounts was derived with 6 degree-of-freedom. The exciting forces at the center of mass of the compressor were estimated from the acceleration data measured at compressor shell. Compressor-pipe system was modeled numerically. The accelerations of compressor and pipe were predicted numerically by using the estimated exciting force. A new shape of pipe model was proposed to reduce the vibration. In the prediction by the method in this paper, the maximum acceleration of the pipe could be reduced by 53.7 % at the steady-state and by 12 % at the transient process. In the real experiments, the maximum acceleration of the pipe was reduced by 54.2 % at steady-state and 14.7 % at the transient process. It was verified that the numerical results showed good agreement with experimental results.

• Structural Engineering and Mechanics
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• 제65권3호
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• pp.349-357
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• 2018

An extensive research was undertaken to study the vibration serviceability of a long-span and light-weight floor subjected to human loading experimentally and numerically. Specifically, heel-drop test was first conducted to capture the floor's natural frequencies and damping ratios, followed by jumping and running tests to obtain the acceleration responses. In addition, numerical simulations considering walking excitation were performed to further evaluate the vibration performance of a multi-panel floor under different loading cases and walking rates. The floor is found to have a high frequency (11.67 Hz) and a low damping ratio (2.32%). The comparison of the test results with the published data from the 1997 AISC Design Guide 11 indicates that the floor exhibits satisfactory vibration perceptibility overall. The study results show that the peak acceleration is affected by the walking path, walking rate, and adjacent structure. A simpler loading case may be considered in design in place of a more complex one.