Search | Korea Science

Kim, Byung-Ghun;Kim, Yun-Chul;Chai, Jang-Bom
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
- /
- 2008.04a
- /
- pp.413-415
- /
- 2008
In this paper, the new algorithm which eliminates structural noise and extracts the impact signature from the measured vibration signal is developed. We studied how the transient vibration signal due to the impact is distorted while propagating through the structure. Also the characteristics of noise generated by flow and the mechanical components are analyzed. The developed method is verified in the model plenum and the flow system in the laboratory. Results show the significant improvement in the sensitivity and accuracy.
PDF

이영신;최명환;류충현
- Journal of KSNVE
- /
- v.8 no.4
- /
- pp.623-631
- /
- 1998
The free vibration analyses of the isotropic and composite(CFRP, GFRP) rectangular plates with point supports at the free edge and middle position are performed. The natural frequencies and nodal patterns of plates with point supports are experimentally determined by impact testing using an impact hammer. To compare and verify these experimental results, the finite element analysis is also carried out. The effect of the point support position, the number of point supports, and the anisotropic parameters on the natural frequencies and nodal patterns of cantilevered rectangular plates are investigated.
PDF

이영신;최명환;류충현
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
- /
- 1997.10a
- /
- pp.414-419
- /
- 1997
The free vibration analysis of cantilever CFRP and GFRP composite rectangular plates with point supports at the free edge and interior position is performed. The natural frequencies and mode shapes of plates are experimentally determined by impact testing using an impact hammer. To compare and verify these experimental results, the finite element analysis is also carried out and the non-dimensional frequency parameters are compared with FE analysis results. The effects of the number and location of the point support on the frequencies are examined. In the experimental results, it is found that a significant increase in frequencies occurs when the point supports are added on certain parts of plates.
PDF

이현종
- Journal of Korea Foresty Energy
- /
- v.18 no.2
- /
- pp.55-61
- /
- 1999
This study was carried out to investigate the influence of viscoelastic properties(or chemical composition) of a series of ethylen-viny1 acetate copolymers on impact noise and vibration damping of wood/polymer/wood sandwich composites. The impact noise and vibration damping of composites were very sensitive to the state of molecular motion of polymer. The noise and vibration damping of composites were maximum when the polymer was under the glass transition(vinylacetate 55~75%) at the test-temperature, and minimum rubbery state(vinyl-acetate 47~20%) or glassy state(vinylacetate 100~87%). The polymer under glass transition reduced the impact noise by 6~12 dB.
PDF