RECOVERY OF IMPACT SIGNATURES IN MACHINE STRUCTURES

被引:11
作者
MCCARTHY, DJ [1 ]
LYON, RH [1 ]
机构
[1] MIT,DEPT MECH ENGN,CAMBRIDGE,MA 02139
关键词
D O I
10.1006/mssp.1995.0036
中图分类号
TH [机械、仪表工业];
学科分类号
0802 ;
摘要
Reciprocating machines are difficult to diagnose using traditional frequency domain techniques because they generate predominantly transient vibrations which have a broad frequency content. We have found that transient vibrations, like those generated by valve impacts in a reciprocating compressor, are best analysed in the time-domain. Unfortunately, by the time the vibrations reach the surface of the machine where we can measure them non-invasively, reverberation and dispersion have disfigured them so that they look nothing like their originating forces. In order to convert them into a useful form, where they can be characterized in terms of timing and strength on a cycle-by-cycle basis, the vibration signal can be compressed by filtering it with the inverse of the structural transfer function. This is a straightforward process if the exact transfer function is known; however, in practice we expect to have simply a 'typical' transfer function from a nominally identical machine. Additional transfer function variability results from changes in machine operating conditions such as temperature and load. The inverse-filtering process can be made robust to transfer function variability through a combination of cepstral-smoothing and minimum-phase processing. In addition, if a cepstral comb window is incorporated into the signal processing scheme, multiple impact signatures can be removed. (C) 1995 Academic Press Limited
引用
收藏
页码:465 / 483
页数:19
相关论文
共 11 条
  • [1] Lyon R.H., Machinery Noise and Diagnostics, (1986)
  • [2] Kim J.T., Lyon R.H., Mechanical Systems and Signal Processing, 6, pp. 1-15, (1992)
  • [3] Tohyama M., Lyon R.H., Journal of the Acoustical Society of America, 91, pp. 2805-2812, (1992)
  • [4] Gibson R.G., Phase Variability of Structural Transfer Functions., (1984)
  • [5] McCarthy D.J., Gaberson H.A., The Systems Engineering Approach to Mechanical Failure Prevention, Proceedings of the 47Th Meeting of the Mechanical Failures Prevention Group, pp. 349-358, (1993)
  • [6] Liu L., Lyon R.H., Proceedings of Noise-Con, 91, pp. 633-640, (1991)
  • [7] Tohyama M., Lyon R.H., Journal of the Acoustical Society of America, 89, pp. 1701-1707, (1991)
  • [8] Robinson E.A., Treitel S., Geophysical Signal Analysis, (1980)
  • [9] Oppenheim A.V., Shafer R.W., Discrete-Time Signal Processing, pp. 768-825, (1989)
  • [10] Tohyama M., Lyon R.H., Journal of the Acoustical Society of America, 86, pp. 2025-2029, (1989)