• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.588-593
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• 2012

Nowadays, various forms of electro-optical rifle scope have been developed and used in order to enhance the accuracy of small arms. However, firing shock acceleration has characteristics of pyroshock having a big acceleration value with very short duration time, which the electro-optical scopes should be designed to sustain. In this paper, the firing shock acceleration, which is transmitted to the electro-optical scope, was measured and SRS (Shock Response Spectrum) analysis was performed by using the measured firing shock acceleration. Furthermore, a shock test condition using a drop-table shock tester, which can simulate the actual firing shock acceleration, was devised. The devised shock test condition will be utilized to test the electro-optical scope itself before attaching it to the small arms.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.34-39
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• 1998

This paper describes a evaluation method of sound power radiated from the vibrating faces of a single stage gear box using sound radiation. The vibration caused from meshing gears is transmitted to the gear box faces through shafts and bearings. A Boundary Element Method (BEM) is developed to calculate the sound power radiated from the faces with their velocity response which is based on the Building Block Approach (BBA). Radiation efficiency as well as the sound intensity on the surface of the gear box is also calculated. Sound power of the gear box is larger in the case that bearings have offset to the wall of the gear box than that bearings are on the center of the gear box. The sound power increases with the augmentation of the offset.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.14-21
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• 2020

The automotive seat appropriately absorbs the vibrations or shocks transmitted through a vehicle when it is in operation so as to provide a comfortable ride for passengers. In this study, the structural strength and durability of each model were investigated using structural analysis. The natural and critical frequencies at the seat were analyzed through vibration analysis. Through the results of this study on automotive seat frame models, the durability against the load and vibration is shown to be dependent on the configuration of the model.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.151-158
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• 2008

The clutch system is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission. Recently, the engine power of automobile has been continuously increased because of customer's demand for the bigger one. As the engine power is increased, the vibration transmitted to the hydraulic clutch operating system has been increased. Therefore the demand for the reduction of clutch pedal vibration during the operation has been increased. This paper describes the pressure pulsation reduction characteristics of the damper cylinder which is applied to the hydraulic clutch operating system. And the purpose of this study is to propose an analysis model and investigate the effect of the design variable variations for the hydraulic clutch system. Especially, we studied the effect of damper cylinder parameter variations on the hydraulic clutch system performance.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.11
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• pp.73-82
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• 2008

A dynamic model of reducer for generating facility of electric pourer having bevel gear pair and planetary gear train is developed by lumped method. The model accounts for the shaft and bearing flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of bevel gear pair and planetary gear train are considered. Exciting forces of high reducer for generating facility of electric power areconsidered as the mass unbalance of the rotors, misalignment and a function of gear transmission error. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not critical speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.513-518
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• 2011

In cruise ships, it is inevitable to arrange the cabins near by the noisy areas, such as ventilation fan, HVAC machinery and funnel casing etc. The noise is propagated to the cabins by way of mount, foundation and deck. The transmitted noise to cabin is affected by mount and foundation structure. It is well-known that most of the structure-borne noise can be reduced by the flexible mount. However, when the foundation of machinery is designed inappropriately, it can make noise problems in cabins. In this paper, the effect of foundation on noise reduction is studied through the numerical analysis and mock up test. The dynamic performance of foundation is investigated from the viewpoint of the impedance and noise reduction in cabin.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.93-99
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• 2008

The clutch is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission. Recently, the engine power of automobile has been continuously increased because of customer's demand for the bigger one. As the engine power is increased, the vibration transmitted to the hydraulic clutch operating system has been increased. Therefore the demand for the reduction of clutch pedal vibration during the operation of the clutch system has been increased. This paper describes the pressure pulsation reduction characteristics of the damper cylinder which is applied to the hydraulic clutch operating system. And the purpose of this study is to confirm the availability of a simulation model and investigating the test results of hydraulic clutch operating system. The test results are compared with the simulation results. Therefore it may be concluded that the simulation model and test results will be very useful f3r the design of hydraulic clutch damper cylinder.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.104-108
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• 2002

In this study, the dynamic absorbing system for the shoulder-fired system with high-level-impact force has been investigated. for this purpose, firstly, mathematical model based on the short recoil system has been constructed. In order to design the dynamic absorbing system, parameter sensitivity analysis and parameter optimization process have been performed under constraints of moving displacement and transmitted force. In order to enhance the efficiency of energy dissipation, the stroke-dependent variable damping system has been analyzed. finally, the performance of the designed dynamic absorbing system has been evaluated by simulation with respect to the benchmark system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.968-974
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• 2004

Automakers have been forcing their suppliers to guarantee qualities of parts. Then, the suppliers have met the fundamental quality requirements such as dimensions and functions, but they could not sufficiently satisfy the automakers' noise requirements yet because automatic noise inspection systems were little successfully adopted In mass-production lines. This study tried to develop a system for automatically checking noise radiated from a rotating engine part and filtering parts emitting noise higher than criteria: the upper limits of a overall noise level or a noise spectrum. A commercial noise measurement system was used for measuring noise, and then the noise data was transmitted to a governing program through OLE(object, linking and embedding) functions. The governing program, belonging to a total noise inspection system managed the noise measurement and analysis. This system was successfully adapted for distinguishing bad parts according to the noise criteria.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.292-293
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• 2014

Transfer Path Analysis is technique predicting transmitted energy through each path. Using the Transfer Path Analysis, structure-borne noise and air-borne noise can be predicted from the system. In this study, however, the Transfer Path Analysis to target only the structure-borne noise due to the noise radiated from the vibrating panel was performed. Predicted noise by the Transfer Path Analysis and measured noise by the experiment were a high correlation. We confirmed the validity of the Transfer Path Analysis through the analysis of these results, showed how to apply the Transfer Path Analysis.