• 한국소음진동공학회논문집
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• 제14권4호
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• pp.287-294
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• 2004

Dynamic Load/unload (L/UL) mechanism is an alternative to the contact start stop (CSS) technology which eliminates striction and wear failure modes associated with CSS. Inertia latch mechanism becomes important for mobile disk drives because of non operating shock performance. Various types of latch designs have been introduced in hard disk drives to limit a rotary actuator from sudden uncontrolled motion. In this paper, a single spring inertia latch is introduced for a small form optical disk drive, which uses a rotary actuator for moving an optical pick-up. A new small inertia latch with sin91e spring is designed to ensure both feasible and small size. The shock performance of the new inertia latch is experimentally verified.

• 소음진동
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• 제11권2호
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• pp.241-248
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• 2001

The present paper describes experimental and computational work to augment the magnitude of the impulsive wave. An experiment was performed using a simple shock tube with an open end and numerical calculations were carried out to solve the unsteady, axisymmetric, inviscid, compressible governing equations. The control strategy applied was to alter the exit geometry of a straight tube to a sudden enlargement tube and a flare tube. The effects of the configurations of the tube exit on the magnitude of the impulsive wave were investigated over the range of the weak shock Mach number from 1.01 to 1.10. The results obtained were compared to those of the straight tube tests. The numerical result predicted the magnitude of the experimented impulsive waves with a good accuracy. The present passive control technique enabled the magnitude of the impulsive wave to augment by about 23 percent, compared to that of the straight tube of no control.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1015-1021
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• 2002

Optical disk is the media which is used generally in data storage device, but it has a disadvantage in the vibration by spinning and the shock. For overcoming these disadvantage, we must control the optical disk to minimize the focusing error and tacking error. The present study investigates the disk profile for minimizing the focusing error subjected to environmental shock and weight of the disk. In this study, the disk is assumed to be a cantilever beam to determine the disk profile for the minimum displacement as to the shock considering only the first mode. Also, for the optimally determined profile by ADS program this paper recalculate the robust caltilever profile by using orthogonal array and ANOM.

• Journal of Mechanical Science and Technology
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• 제19권2호
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• pp.605-617
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• 2005

A sudden discharge of mass flow from the exit of a duct can generate an impulsive wave, generally leading to undesirable noise and vibration problems. The present study develops an understanding of unsteady flow physics with regard to the impulsive wave discharged from a duct, using a numerical method. A second order total variation diminishing scheme is employed to solve three-dimensional, unsteady, compressible Euler equations. Computations are performed for several exit conditions with and without ground and wall effects under a change in the Mach number of an initial shock wave from 1.1 to 1.5. The results obtained show that the directivity and magnitude of the impulsive wave discharged from the duct are significantly influenced by the initial shock Mach number and by the presence of the ground and walls.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.861-862
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• 2008

One of trend of portable devices is convergence with other devices, especially with navigation system. This converged system is generally called PND (Personal Navigation Device). This detachable device is developed for personal entertainment in everyday life and navigation system when deriving, so it should meet the specification of vehicle thermal environment, anti-vibration as well as the anti-shock by sudden drop. In this paper, the way to design the hard disk drive damper with CAE, is introduced to get a reliable system from the beginning of the design step.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.177-182
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• 2004

Electronic products are subjected to many different types of shock environment. As the Optical Disc Drive (ODD) market grows, the number of failures related to shock increases. Therefore, it is necessary to improve the performance of cushion package as well as the product design. Cushion materials such as expanded polystyrene are often used to protect electronic products from shock environment. In this paper, the drop analysis of the cushion package f3r optical disc drives was carried out with the explicit method of LS-DYNA and verified by the drop test. For the optimization of package, response surface approximation model was created using central composite design. As a result, cushioning performance was improved under the critical condition and practical design guidelines of cushion package were suggested.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.94-96
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• 2014

Press machine has advantage over other manufacturing machine which can produce large quantities of products in short time so it is widely used in lots of industrial sectors. However, vibration problems may occur when operating a high pressure. It has been subjected to the condition monitoring vibration sensors attached to the main point. We perform the maintenance before a failure occurs, the system receives a high load. In this paper, in order to determine the structural characteristics for the transport system to conduct the vibaration and shock analysis.

• 대한기계학회논문집B
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• 제21권10호
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• pp.1294-1302
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• 1997

For the purpose of investigating the impulsive noise at the exit of high-speed railway tunnel and the pressure transients inside the tunnel, experiments were carried out using a shock tube with an open end. A great deal of experimental data were obtained and explored to analyze the peak pressures and maximum pressure gradients in the pressure waves. The effects of the distance and cross-sectional area ratio between two-continuous tunnels on the characteristics of the pressure waves were investigated. The peak pressure inside the second tunnel decreases for the distance and cross-sectional area ratio between two tunnels to increase. Also the peak pressure and maximum pressure gradient of the pressure wave inside the second tunnel increase as the maximum pressure gradient of initial compression wave increases.

• 한국추진공학회지
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• 제7권3호
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• pp.15-21
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• 2003

본 연구에서는 다공관의 출구로부터 전파하는 충격성 소음의 전파특성을 실험적으로 파악하였다. 다공관은 공극율, 구멍지름 그리고 관의 길이를 각기 다르게 제작하여 충격파 관 출구에 부착하여 실험하였다. 충격파 전파마하수는 실제의 적용조건을 참고하여 1.02-1.2의 범위로 하였다. 지향성은 근음장과 원음장으로 구분하여 측정하였다. 또한 충격성 소음원인 펄스파의 전파과정을 조사하기 위하여 쉴리렌 광학장치를 이용하였다. 실험결과로부터 다공관의 소음저감 성능은 음장조건에 좌우됨을 알았다. 즉 근음장 조건에서는 다공관의 공극율과 관의 길이가 소음저감에 다소간의 영향을 미치지만, 원음장 조건에서는 다공관이 충격성 소음의 저감에 거의 기여하지 못하였다. 이와 같이 음장조건에 따라 충격성 소음의 저감성능이 다르게 되는 것은 근음장 조건에서는 관축방항으로 강한 지향성을 보이지만, 원음장 조건에서는 모든 방향으로 같은 세기로 전파하는 무지향성이기 때문이다.

• 소음진동
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• 제4권3호
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• pp.345-352
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• 1994

Electronic products can be subjected to many different forms of shock. These shocks are usually experienced during transporting the electronic products from a manufacturer to customers. Drop tests are performed to test the product fragility before shipment. Package cushioning materials are often used to protect electronic products from severs shock environments. In the present paper, an algorithm to predict the shock responses of the main mechanical parts is developed by use of the shock analysis in which the modal parameters extracted from vibration test are used. These results are in good agreement with the results of drop test. By use of the shock response prediction algorithm developed herein, it is possible to predict the results of drop test at various drop directions and also to select the optimal package cushioning materials.