• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.2
• /
• pp.185-191
• /
• 2013

This paper presents a new method for roller design of IRB(isolation roller bearing) seismic isolation device using experimental evaluation. Three layered plate is adopted for the IRB in which the upper plate is placed on x direction and the lower plate is placed on y direction. The rollers placed in each plate make a plate movement. The roller is then optimally designed using variable geometric conditions. Stress distribution depends on the diameter and length of the roller and hence this is used for the determination of optimal geometry of the roller. In the experimental evaluation, it is observed that stress concentration at the end sides of roller is decreased and geometric coefficients depend on crowning dimension. In addition, in order to determine optimal design parameters of the roller the plastic deformation and friction are experimentally identified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.11
• /
• pp.1213-1222
• /
• 2008

In this paper, the isolation of the IBBD array antenna is analyzed as functions of the element spacing and the height of the flat plate inserted between array elements for the intelligent antenna system. It is found that the isolation between array elements improves with increasing the array spacing. The array configuration with the plate between the elements is enhanced by about 13 dB more In the isolation than the one without the plate. The plate-inserted $4{\times}4$ elements IBBD array antennas are fabricated and the radiation characteristics are measured and analyzed for the various heights of the plate. It is found that the gain decreases slightly with increasing the height of plate but the shape of radiation pattern does not show a remarkable change.

• Structural Engineering and Mechanics
• /
• v.81 no.6
• /
• pp.691-703
• /
• 2022

To obtain the seismic response of lead-cored rubber, shape memory alloy (SMA)-rubber isolation Plate-shell Integrated Concrete Liquid-Storage Structure (PSICLSS), based on a PSICLSS in a water treatment plant, built a scale experimental model, and a shaking table test was conducted. Discussed the seismic responses of rubber isolation, SMA-rubber isolation PSICLSS. Combined with numerical model analysis, the vibration characteristics of rubber isolation PSICLSS are studied. The results showed that the acceleration, liquid sloshing height, hydrodynamic pressure of rubber and SMA-rubber isolation PSICLSS are amplified when the frequency of seismic excitation is close to the main frequency of the isolation PSICLSS. The earthquake causes a significant leakage of liquid, at the same time, the external liquid sloshing height is significantly higher than internal liquid sloshing height. Numerical analysis showed that the low-frequency acceleration excitation causes a more significant dynamic response of PSICLSS. The sinusoidal excitation with first-order sloshing frequency of internal liquid causes a more significant sloshing height of the internal liquid, but has little effect on the structural principal stresses. The sinusoidal excitation with first-order sloshing frequency of external liquid causes the most enormous structural principal stress, and a more significant external liquid sloshing height. In particular, the principal stress of PSICLSSS with long isolation period will be significantly enlarged. Therefore, the stiffness of the isolation layer should be properly adjusted in the design of rubber and SMA-rubber isolation PSICLSS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.05a
• /
• pp.249-252
• /
• 2003

This paper propose an advanced circuit for fingerprint sensor signal processing. We increased the voltage between ridge and valley by modifying the parasitic capacitance eliminating circuit of sensor plate. The analog to comparator was designed for comparing the sensor signal voltage with the reference signal voltage. We also propose an exective isolation strategy for removing noise and signal coupling of each sensor pixel. The 128$\times$144 pixel fingerprint sensor circuit was designed and simulated, and the layout was performed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.04a
• /
• pp.524-525
• /
• 2009

Heavy-weight impact noise(HN) is the most irritating noise in Korean apartment houses. It has been proclaimed standard floor system of 210mm thick slab with isolation material in the wall type structure. But this regulation is applied only new construction field and is not considered remodeling field. In general, the LN can be reduced by using isolation material but HN is known as relating with stiffness, strength & boundary condition of slab. Therefore it is difficulty in improving the HN on remodeling field. In this study, We conducted the reinforcement of concrete slab using C.F.S.(carbon fiber sheet), steel plate and steel beam after on-dol with isolation material on the remodeling field. As the test results, It appeared using C.F.S was no improved but using steel plate & steel beam were a little improved on HN.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.3
• /
• pp.185-191
• /
• 2007

For the seismic performance enhancement of residential flat plate structure and for the selection of earthquake records, the possibility of base isolation is evaluated and the time history results are reviewed. By evaluating a base isolated stiffness, a target period, and an envelope curve analysis, seismic performance of structure, which has strong rotational mode, is evaluated. For the propriety evaluation of earthquake records usage and scaling method, time history analysis is done with variables such as DBE(design base earthquake) level, MCE(maximum considerable earthquake) level, and 1.4DBE level. From the analysis results, following conclusions can be made; the earthquake records, which are used in base isolation analysis, should be selected by similar soil type which the structure is considered, and should be intensity scaled in a range of mean ${\pm}$ standard deviation of code based design response spectrum.

• Journal of Life Science
• /
• v.22 no.6
• /
• pp.723-729
• /
• 2012

Filter plate microbial trap (FPMT) was invented as an in situ cultivation device for the isolation of bacteria from natural environments. FPMT consists of a medium and membrane filters (0.45 ${\mu}m$ pore size) and microorganisms and compounds can be moved freely moved into the medium. This device was applied to two soil samples of Greenland. The microbial diversity of both soil samples by FPMT was higher than that by the conventional Petri dish-based method. Moreover, novel bacterial species were isolated by FPMT. The new FPMT is effective for in situ cultivation of natural samples and could be applicable to the isolation of uncultivable microorganism.

• Computational Structural Engineering
• /
• v.3 no.1
• /
• pp.71-81
• /
• 1990

The isolation system is installed at the base of a structure for reduction of the earthquake damage to the structure. In the 1970', when the laminated rubber bearing(LR type) is developed, the isolation system is put in practice. And recently a new isolation system(SR type), including the laminated rubber bearing with the friction plate beneath, is developed. In this thesis, a study on the base isolation effect, for various of the isolation system and structure properties, is performed. The results of this parameter study show that the isolation system can reduce the earthquake damage of the building structures significantly. As the period of isolation system increases, the isolation effect increases and converges to zero damage. As the number of story increases, the isolation effect reduces. It is found that SR type isolation system is more effective than LR type because SR type base isolation system reduces acceleration, drift and total displacement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.477-482
• /
• 2002

This research is concerned with the study of an active vibration absorber using piezoelectric actuators and Isolation pad. The active isolation system consists of 4-pairs of PZT actuators bonded on the surface of an aluminum plate and a passive damping material. The active system is connected to the passive system in series. The Signals of the accelerometers are fed into the PZT actuator through the controller. We proposed a new control technique which can deal with the shock as well as the base excitation in this study. The Positive Acceleration Feedback(PAE) tuned to the natural frequency of the vibration isolation system is used to suppress the vibrations caused by the shock using the top accelerometer signal. The Negative Acceleration Feedback (NAF) based on the base acceleration signal is used to counteract the base motion. Experimental results show that the proposed active vibration isolation system can suppress vibrations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.401-406
• /
• 2013

This paper presents experimental evaluation of IRE (isolation roller bearing) seismic isolation device. From the combination of base isolation on the IRE system displacement response spectrum and acceleration response spectrum, the compressive strength and the coefficient of friction experiments. Also the IRE system is evaluated by environment test according to KS standards. Both the resonance and seismic experiments using a combination of the IRE and Natural Rubber Bearing (NRB) are performed in order to analyze the seismic isolation of the IRE system dynamic characteristics. For the given load and exciting frequency, the resonant frequency becomes lower, but the resonant magnification remains to be same. However, it is shown that when we consider the IRE only, the vibration on the table with the horizontal movement and the independent horizontal displacement due to the rolling motion of the plate and roller are significantly reduced. This result verifies that the proposed optimal design method of the IRE system is very effective.