• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.272-279
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• 2005

In this study the optimal isolation system for the prototype HIFD(high impulsive force device) is investigated. For this purpose, firstly, the dynamic behavior of a human body and a transmitted force under specific operation conditions are analyzed through a series of experimental works using the devised test setup. In order to design the optimal dynamic absorbing system, the parameter optimization process is performed using the simplified isolation system model based on the experimental results of linear impulse and transmitted force. Finally, under the parameters satisfying the constraints of the buffering displacement and the transmitted force, the performance of the designed isolation system for the prototype HIFD is evaluated by experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.883-888
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• 2002

This study describes the limit and application of the two-microphone impedance tube method to the sound transmission loss measurement of several sound isolation materials with different physical properties. For the sound isolation materials having small flexural rigidity, it is shown that the two-microphone impedance tube method is validated to practically measure the sound transmission loss. For the sound isolation materials having large flexural rigidity, on the other hand, it is found that the two-microphone impedance tube method is no longer valid to measure the sound transmission loss because the regions of resonance and mass law are moved into the higher frequencies. In addition, in order to accurately measure the sound transmission loss of sound isolation materials, their size should be decided based on the consideration of the effect of acoustic excitation on their vibration response.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.176-179
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• 2005

To control the vibration transmitted to the precision instruments from ground has always been of great interest among the researchers. This paper proposes a single axis vibration isolation system which can be used as a module far a table top six axis isolator for highly precise measurement and actuation system. The combined active-passive isolation principle is used for vertical vibration isolation by mounting the instrument on a passively damped isolation system made of Elastomer along with the active stage in series which consists of very stiff piezo actuator. The active stage works in combination with the passive stage for working as a very low frequency vibration attenuator. The active stage is isolated from the payload disturbance through the Passive stage and thus modularity in control is achieved. This made the control algorithm much easier as it does not need to be tuned to specific payload.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.950-953
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• 2005

Floor impact sounds from two different floor systems were measured. One of the two floor systems is a dry floor system (with 150mm concrete slab) and the other is a standard floor system (210mm concrete slab). Real impact sources such as jumping and running of children were used as well as standard impact sources (bang machine, impact ball and tapping machine) to evaluate sound Isolation of the two floor systems. Subjective evaluations of the floor impact sound isolation performance for the two systems were also conducted by the methods of 3 scales & 9 categories, paired comparison and semantic differentials. Measurement results indicate that floor impact sound isolation performance of the dry floor was better than that of standard floor in both cases of real and standard impact sources. The subjects in auditory experiments also evaluated the dry floor as a better sound isolation system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.191-195
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• 2003

충격음 저감재의 동탄성계수와 감쇠계수는 차단성능을 평가하는데 있어 중요한 물성치가 된다. 저감재의 동탄성계수는 뜬바닥구조의 고유진동수를 결정짓게 되며, 저감재의 동탄성계수가 높을수록, 즉 고유진동수가 높아짐에 따라 실험실 경량충격음레벨 저감량은 지수함수적으로 감소됨을 실험을 통해 알 수 있다. 또한, 저감재를 포함한 뜬바닥구조를 1자유도 진동계로 가정한 이론값과 실험실 경량충격음레벨 저감량의 결과가 비교적 잘 일치하는 것으로 나타났으며, 이 때 감쇠계수의 영향은 반드시 고려되어야 한다.

• Smart Structures and Systems
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• v.29 no.4
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• pp.549-560
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• 2022

The optimum damping and tuning frequency ratio of the tuned mass damper-inerter (TMDI) for the base-isolated structure is obtained using the numerical searching technique under stationary white-noise and filtered white-noise earthquake excitation. The minimization of the isolated structure's mean-square relative displacement and absolute acceleration, as well as the maximization of the energy dissipation index, were chosen as the criteria for optimality. Using a curve-fitting technique, explicit formulae for TMDI damping and tuning frequency for white-noise excitation are then derived. The proposed empirical expressions for TMDI parameters are found to have a negligible error, making them useful for the effective design of base-isolated structures. The effectiveness of TMDI and its optimum parameters are influenced by the soil condition and isolation frequency, according to the comparison made of the optimized parameters and response with different soil profiles. The effectiveness of an optimally designed TMDI in controlling the displacement and acceleration response of the flexible isolated structure under real and pulse-type earthquakes is also observed and found to be increased as the inertance mass ratio increases.

• Broadcasting and Media Magazine
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• v.3 no.4
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• pp.56-71
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• 1998

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.4
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• pp.32-42
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• 2007

The substrate resistance is modeled to estimate the performance degradation of analog circuits by substrate noise in a $0.35{\mu}m$ twin-well non-epitaxial CMOS process. The substrate resistance model equations are applied to the P+ guard-ring isolation structure and a good match was achieved between measurements and models. The substrate resistance is divided into four types and a semi-empirical model equation is obtained for each type of substrate resistance. The rms(root-mean-square) error of the substrate resistance model is below 10% compared with the measured resistance. To apply this substrate resistance model to the P+ guard ring structure, ADS(Advanced Design System) circuit simulation results are compared with the measurement results using Network Analyzer, and relatively good agreements are obtained between measurements and simulations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.140-141
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1247-1252
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• 2007

The machine equipment of the building inside occurs the vibration. In order to reduce this vibration spring, rubber pad is used. But efficiency of this classical mount is restricted at specific frequency. Also maximum efficiency design is complicated. This paper proposes and examines a attached mass isolation system that is used to reduce transmitted vibrations from machines onto their floor support. With attached mass the low frequency performance is improved overall. The performance is showed in 2 degree of freedom model test. And the proposed isolator has been validated by dynamic test and good agreement between theoretical and experimental results has been obtained.