• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.286-290
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• 2000

Optimal neuro-control algorithm is extended to the control of a multi-degree-of-freedom structure. An active mass driver(AMD) system on the top roof is used as an exciter. The control signals are made by a multi-layer perceptron(MLP) which is trained by minimizing a sub-optimal performance index. The performance index is a function of both the output responses and the control signals. Structure having nonlinear hysteretic behavior is also trained and controlled by using proposed control algorithm. In training neuro-controller, emulator neural network is not used. Instead, sensitivity-test data are used. Therefore, only one neural network is used for the control system. Both the time delay effect and the dynamics of hydraulic actuator are included in the simulation. Example shows that optimal neuro-control algorithm can be applicable to the multi-degree of freedom structures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1065-1070
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• 2000

High speed rotor test rig was developed for flexible rotor systems which have its bending critical speed at 14000 rpm. In designing the flexible rotor systems, operating speed have to be escaped from the critical speed, due to large vibration. In this paper, dynamic characteristics of the rotor systems were analyzed and compared with test results. And the effect of allison ring damper and rotor balancing were examined both theoretically and experimentally. Finally, the magnitude of vibration was largely reduced at the critical speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.354-359
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• 2012

Improvement of structure-borne noises in the vehicle compartments has been one of the primary concerns in the development of vehicles. The booming is an annoying low frequency interior noise and vibration in vehicle. But it is difficult to reduce the structure-born booming noise in traditional method - trial and error within the shorten development schedule. So in present, the structure dynamic modification (SDM) method helpful to predict the effect of the local mass, stiffness, and damping is introduced. So in order to reduce the interior booming noise, the SDM was performed, and verified with modal test result. It was shown that the interior booming noise was reduced as predicted.

• Korean Journal of Computational Design and Engineering
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• v.14 no.2
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• pp.87-95
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• 2009

This paper describes the design of the ossicular replacement prosthesis for the people who have problem of hearing because of middle ear disease. Also the simulation results of the designed product for verification by finite element analysis software (ABAQUS) are presented. New model is applied to middle ear FE analysis which was generated in previous study. The full replacements of ossicular prosthesis for ossicles (malleus, incus and stapes) are made of Hydroxyapatite and Titanium. Although other existing prosthesis models consider only sound amplification effect, current type has damper system which is operating on the audible frequencies. High frequency sound transmitted to inner ear can be reduced and the prosthesis and inner ear can be prevented from damage.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.307-307
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• 2000

The swing motion of the spreader during and after movement causes an efficiency problem of position control in unmaned gantry crane. The objective of this research is to design implementable stabilizing controllers that minimize the swing motion of spreader in precise position control. The dynamic equations related to trolley, rope, and spreader are derived. For constitute a similar actual system, we introduced a conception of spring and damper in the connector. It is located between the trolley and link that is used in stead of rope. We derived dynamic equation by appliance that friction and external disturbance are occurred to the connector. We constituted of position servo system and velocity servo system for the control of position and velocity of the trolley and constituted of lag compensator system for the control of sway of the spreader. And we will show an effect of the proposed system in this research finally.

• Journal of Power System Engineering
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• v.18 no.3
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• pp.36-41
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• 2014

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.460-465
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• 2002

The nonlinear vibration of the CRT shadow mask is analyzed in consideration of the V-shaped tension distribution and the effect of wire impact damping. The reduced order FEM model of the shadow mask is obtained from dynamic condensation for the mass and stiffness matrices. Damping wire is modeled using the lumped parameter method to effectively describe its contact interactions with the shadow mask. The nonlinear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. The analysis model of the shadow mask with damping wires is experimentally verified through impact tests of shadow masks performed in a vacuum chamber. Using the validated analysis model of the shadow mask with damping wires, the‘design of experiments’technique is applied to search fur the optimal damping wire configuration so that the vibration attenuation of the shadow mask is maximized.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.117-122
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• 2010

The shock performance of hard disk drives has been a serious issue for Car PC. Since the vibration and disturbances from a car gives an adverse effect on a HDD of Car PC, it is necessary to protect a HDD from them. In this study, passive vibration attenuation system for a vehicle HDD was developed. Acceleration from the ground through the tire and suspension system was measured to figure out the frequency translated to Car PC. Critical frequency to Car PC was determined by exciting it with a shaker and measuring a data transmitting speed from HDD. A newly designed vibration attenuation system was fabricated to protect HDD from the acceleration. It was shown that the developed system had an excellent vibration attenuation ability.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.731-737
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• 2002

Nonlinear vibration of the CRT shadow mask with impact damping wires is analyzed in consideration of the mask tension distribution and the effect of wire impact damping. A reduced order FEM model of the shadow mask is obtained from dynamic condensation of the mass and stiffness matrices, and damping wire is modeled using the lumped parameter method to effectively describe its contact interactions with the shadow mask. The nonlinear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. The analysis model of the shadow mask with damping wires is experimentally verified through impact tests of shadow masks performed in a vacuum chamber.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.193-200
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• 2002

Simple spring-damper-mass models have been widely used to investigate whole-body vortical biodynamic response characteristics of the seated vehicle driver. Most previous models have not considered the effect of wobbling masses; i.e. heart, lungs, liver, intestine, etc. In this study, 4 -DOF seated driver model including one non-rigid mass representing wobbling visceral mass, 5-DOF model including intestine, and 10-DOF model including five lumbar vertebral masses were proposed. The model parameters were identified by a combinatorial optimization technique. simulated annealing method. The objective function was chosen as the sum of error between model response of seat-to-head transmissibility and driving point mechanical impedance and those of experimental data for subjects seated erect without backrest support. The model response showed a good agreement with the experimental response characteristics. Using a 10-DOF model, calculated resonance frequency of lumbar spine at 4Hz was matched well with experimental results of Panjabi et al.