• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.748-753
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• 2000

Nowadays, many studies and researches in data storage have been carried out and storage capacity is increased. But the limitation of storage capacity is happened for several problems. One of them is spot & pit size in optical and magnetic data storage and another is the resolution of actuators. The problems in spot & pit size is covered by new data storage methods- for example, NFR{Near-Field Recoding) system. But the resolution limit of an actuator doesn't follow up the development of spot & pit size. Because of them, we should improve a resolution of an actuator. Especially, in this paper an actuator is studied and designed for NFR(in using SIL(Solid Immersion Lens) system. It is a dual stage actuator, which consists of a Fine actuator and a Coarse actuator, and should desire 100nm accuracy. But, our actuator system only includes tracking mechanism execpt focusing mechanism which is controlled by slider mechanism used in HDD. Its actuating force generation method is VCM(Voice Coil Motor). The Fine actuator is composed of 4-leaf springs and a bobbin wrapped by coil. The Coarse actuator has Coils and 3-Roller bearings.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.989-999
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• 2006

In this paper, numerical analysis method to perform linear dynamic analysis of bridge considering the road surface roughness and bridge-vehicle interaction when vehicle is moving on bridge is presented. The vehicle and bridge are modeled as three-dimension where contact length of tire and pitching of tandem spring are considered and single truck with 2-axles and 3- axles, and tractor-trailer with 5-axles are modeled as 7-D.O.F., 8-D.O.F., and 14-D.O.F., respectively. Dynamic equations of vehicle are derived from the Lagrange's equation and solution of the equation is obtained by Newmark-${\beta}$ method. The surface roughness of bridge deck for this analysis is generated from power spectral density (PSD) function. Beam element for the main girder, shell element for concrete deck and rigid link between main girder and concrete deck are used. The equations of the motion of bridges are solved by mode-superposition procedures. The proposed procedure is validated by comparing the results with the experimental data by Whittemore and Fenves.