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Lee, Sang-Hyun;Woo, Sung-Sik;Cho, Seung-Ho;Chung, Lan
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2007.05a
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- pp.582-587
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- 2007
In this study, based on the results from the sinusoidal base excitation analyses of a single degree of freedom system with a tuned mass damper (TMD), it is verified that optimal friction force can improve the performance of a TMD like a linear viscous damper which has been usually used in general TMD. The magnitude of the optimal friction increases with increasing mass ratio of the TMD and decreases with increasing structural damping. Particularly, it is observed that the optimized friction force gives better control performance than the optimized viscous damping of the TMD. However, because the performance of the TMD considerably deteriorates when the friction force increases over the optimal value, it is required to keep the friction force from exceeding the optimal value.
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Lee, Soo Il;Kim, Il Kwang
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2014.04a
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- pp.88-89
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- 2014
In dynamic force microscopy, the cantilever oscillates at a resonant frequency, and the tip deflection is measured at this frequency. The cantilever deflection is, however, highly nonlinear, and the surface properties can be embedded in the deflection at the frequencies other than the original resonant frequency of the cantilever. Multifrequency atomic force microscopy includes the excitation and detection of the deflection in two or more frequencies which are higher harmonics or eigenmodes. This can overcome the limitations of conventional atomic force microscope. We reviewed the multifrequency atomic force microscopy and its applications in many fields.
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Hwang, Tai-Sik;Seok, Jul-Ki
- Proceedings of the KIPE Conference
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- 2005.07a
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- pp.240-242
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- 2005
The linear hybrid stepping motors (LHSM) has been widely used due to its simple structure and low cost control. Despite of its attractive features, the conventional LHSM has the multiples of 4th times harmonic reluctance force from excitation current and cogging force from space harmonic of permeance. This paper propose a new LHSM, which the mechanical and electrical phase difference are 45$^{\circ}$. The proposed motor shows a unique ability to deliver low detent force and we propose a closed-loop control scheme to attack the ripple force for high performance applications. An analytical and experimental comparison between conventional and proposed LHSM is evaluated to confirm the effectiveness of the proposed modeling and control scheme.
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Lee, Sang-Hyun;Woo, Sung-Sik;Cho, Seung-Ho;Chung, Lan
- Transactions of the Korean Society for Noise and Vibration Engineering
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- v.17 no.6 s.123
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- pp.553-559
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- 2007
In this study, based on the results from the sinusoidal base excitation analyses of a single degree of freedom system with a tuned mass damper (TMD), it is verified that optimal friction force can improve the performance of a TMD like a linear viscous damper which has been usually used in general TMD. The magnitude of the optimal friction increases with increasing mass ratio of the TMD and decreases with increasing structural damping. Particularly, it is observed that the optimized friction force gives better control performance than the optimized viscous damping of the TMD. However, because the performance of the TMD considerably deteriorates when the friction force increases over the optimal value, it is required to keep the friction force from exceeding the optimal value.
https://doi.org/10.5050/KSNVN.2007.17.6.553 인용 PDF KSCI

심재술;안병하;하종훈;정현출
- Proceedings of the Korean Society of Precision Engineering Conference
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- 1997.10a
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- pp.564-567
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- 1997
In the design of structure the forces acting on the structure are important parameter for noise and vibration control. However, in the complex structure, the forces at the injection point on the structure cannot be measured directly. Thus it is necessary to find out indirect force evaluation method. In this paper forces have been measured with in-situ vibration responses and system information. Three existing techniques of indirect force measurement, viz. direct inverse, principal component analysis and regularization have been compared. It has been shown that multi-vibration responses are essential for the precise estimation of the forces. To satisfy those conditions, Rotary compressor is adopted as test sample, because it is very difficult to measure the injection forces from internal excitation to shell. It has also been obtained that relatively higher force is transmitted though three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation with curvature shell and plate and is investigated the possibility of force evaluation of rotary compressor as a complex structure.
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