• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.940-944
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• 2001

Shock environments are generally classified two categories; One is mechanical shock environments encountered in handling, transportation, and service environments. The other is pyrotechnic shock (or pyroshock) environments generally initiated by firing of an ordnance item to separate or release a structural member of fastener. The objective of this paper is to present a set of shock test methods - specific characteristics induced by many shock test devices, test objects properties, and shock environments. In addition, it is introduced the application of shock test in Korean aerospace development program and others with shock test facilities of Korea Aerospace Research Institute.

• 한국소음진동공학회논문집
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• 제11권7호
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• pp.239-246
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• 2001

The present study addresses the open correction associated with the reflection and discharge phenomena of a weak shock wave from an open end of a duct. The open correction of the weak shock wave is investigated experimentally and by numerical computation. An experiment is made using a simple shock tube with an open end. and computaion is performed to simulate the experimental flow field using the unsteady, axisymmetric compressible. flow governing equations. The results obtained show the an open correction should be involved for shock wave discharge and reflection problems generated from the exit of the duct with an open baffle plate. With a baffle plate less than three times the duct diameter, it is found that the open end correction is a function of both the diameter of the baffle plate and normal shock wave magnitude However, for a baffle plate larger than three the duct diameter it is independent of the baffle plate diametre, The present computations predict the results of shock tube experiment with good accuracy. A new empirical equation for prediction of the open correction is found for the weak shock reflection and discharge phenomena occurring at the open of the duct with and without a baffle plate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.475-479
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• 2011

Leak problem with large pressure drop occurrs non-periodic shock pulsation due to the deterioration of a isolation valve in feed-water recirculation piping system. This paper discusses on the shock vibration and noise occurred due to the effect of acoustical shock pulsations by degradation of the isolation valve in a power site.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1132-1139
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• 2006

Non-contact underwater explosions against surface ship could cause extensive equipment damage during wartime service. Thus, the need to develop methods for the design of shock resistant equipment structures and systems was strongly established. In analytical methods, DDAM(Dynamic Design and Analysis Method) and transient repsonse method are used for ship shock design. In this paper, to analyze the characteristics of DDAM, medium weight shock test, DDAM and transient response analysis for missile system equipment are performed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.189-194
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• 2004

As a disk drive becomes widely used in portable environments, one of the important requirements is durability under severe environmental condition, especially, resistance to mechanical shock. An important challenge in the disk recording is to improve disk drive robustness in shock environments. If the system comes In contact with outer shock disturbance, the system gets critical damage in head-gimbal assembly or disk. This paper describes analysis of a HGA(head-gimbal assembly) in micro MO drives to shock loading during both non-operating state and operating state. A finite element model which consists of the disk, suspension, slider and air bearing was used to find structural response of micro MO drives. In the operational case. the air bearing is approximated with four linear elastic springs. The commercially available finite element solver, ANSYS/LS-DYNA, is used to simulate the shock response of the HGA in micro MO drives. In this paper, the mechanical robustness of the suspension is simuiated considering the shock responses of the HGA.

• 한국소음진동공학회논문집
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• 제20권12호
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• pp.1183-1189
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• 2010

Shock-resistance test for a real equipment for a normal vessel is one of the difficult problem in many cases because of terrible cost and weight. An analysis technique to evaluate the shock resistance in a design stage is necessary, instead In this paper, the process to evaluate the shock resistance of a propulsion motor for naval vessels was presented based on German navy's BV043 regulation. The shock signal to impose the equipment under the test was first evaluated, and was then applied to the structural FE model of the equipment. From the transient FEA, the time history of von-Mises stress was obtained by the mode superposition method. The shock resistance was evaluated using the peak value of the von-Mises stress.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.267-272
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• 2014

In this paper, we analyze the characteristics for the driving shock resistance of the military vehicle through the bump test. Prior to the experiment, theoretical analysis was performed by using the SRS(shock response spectrum) and VRS(vibration response spectrum) analysis method. And we estimated the characteristics for the driving shock resistance of the military vehicle. Bump test was performed using the acceleration sensor and the driving test at a different speed. We evaluated the characteristics for the driving shock resistance of the military vehicle based on the result. And predicted values were compared with the theoretical analysis. In addition, we evaluated the results of the theoretical prediction of the SRS and the VRS analysis. And we evaluate the suitability of the prediction method at military vehicle shock analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.503-504
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• 2010

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.81-86
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• 2012

The shock absorber is very important in various mechanical field. Without the shock absorber, the structure might be broken. For lunar lander, honeycomb shock absorber to absorber the shock by using plastic deformation of honeycomb has been used. It is cheap and simple to use but impossible using again without changing the honeycomb. The oleo-pneumatic type shock absorber is not able to use in the cosmos because it is vacuum and its temperature. This study suggests the hybrid shock absorber combined spring-ratchet mechanical shock absorber and eddy current electromagnetic damper. The ratchet restricts rebound of lunar lander and the spring converts the impact energy to the potential energy of the spring. The eddy current damper dissipates the impact energy by eddy current force without contact between the parts. This hybrid shock absorber is reusable while the honeycomb shock absorber isn't. The impact absorbing test of the hybrid shock absorber was carried out. This paper shows that the compared results the hybrid shock absorber with ratchet and without ratchet and evaluates the possibility of using for lunar lander.

• 소음진동
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• 제11권2호
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• pp.285-291
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• 2001

The impingement of a weak shock wane discharged from the open end of a shock tube upon a flat plate was investigated using shock tube experiments and numerical simulations. Harten-Yee Total Variation Diminishing method was used to solve axisymmetric, unsteady, compressible flow governing equations. Experiments were carried out to validate the present computations. The effects of the flat plate and baffle plate sizes on the impinging flow field over the flat plate were investigated. Shock Mach number was varied in the range from 1.05 to 1.20. The distance between the plate and shock tube was changed to investigate the effect on the peak pressure. From both the results of experiments and computations we obtained a good empirical equation to predict the peak pressure on the flat plate.