Dissertation > Excellent graduate degree dissertation topics show

Structural Modal Parameter Identification and Damage Analysis Based on Vibration Signal

Author: LiuZhen
Tutor: XuYaLan
School: Xi'an University of Electronic Science and Technology
Course: Engineering Mechanics
Keywords: Parameter identification Wavelet transform HHT EMD Structural Damage
CLC: TU311.3
Type: Master's thesis
Year: 2010
Downloads: 260
Quote: 4
Read: Download Dissertation

Abstract


Vibration mode parameter is the main parameter to determine the dynamic characteristics plays a very important role in structural modeling, vibration control, damage detection and structural optimization. In this paper, wavelet transform and Hilbert-Huang transform (HHT) as the main tool for modal parameter identification of problems and structural damage issues were studied. 1. Modal parameter identification method based on the Complex Morlet wavelet transform. Using a complex Morlet wavelet transform signal analysis, the free vibration response of the structure to identify the instantaneous frequency and amplitude by the wavelet ridge corresponding to the scale and the ridge line wavelet coefficients. The relationship between the factor and the center frequency of the complex Morlet wavelet, wavelet factor (N = 2-20) within the scope of the free vibration signal modal parameter identification. As N increases, the vibration signal in the frequency domain resolution has been improved, has a good effect on the modal parameter identification, but the corresponding time domain resolution will reduce the value of N is not always better . Parameter N role is to coordinate the resolution of the frequency-domain and time-domain so as to achieve the best trade-off state. White noise excitation of the structure of the vibration signal modal parameter identification is based on the correlation function theory, Complex Morlet modal parameter identification, and achieved good recognition effect. The use of high-frequency noise signal wavelet transform coefficient is small, effective vibration signal performance characteristics of the low-frequency signal containing white noise vibration modal parameter identification. The above methods are modal parameter identification error can be controlled within the allowable range. (2) the use of EMD to the vibration signal modal parameter identification identification error is less than 5%. For three degrees of freedom and the above structure, the application of HHT method to identify mold modal parameters is not ideal. So the use of the vibration signal added first band-pass filter, and then using HHT modal parameter identification method, identification error is also smaller. Modal parameter identification method based on EMD wavelet transform: the vibration signal EMD decomposition, the decomposition of the intrinsic mode functions (IMF) structural modal parameter identification using wavelet transform method, and the identification error control less than 8%. HHT method modal parameter identification, the vibration signal containing white noise due to the bad effect of the EMD this signal decomposition, identification error. Using modal parameter identification method based on wavelet transform and wavelet packet-based energy method for the analysis of the structural damage. The former is the use of the changes in the characteristics of the modal parameters of the structure before and after the damage to determine the structural damage. Meantime by multiplying the minimum inverse index method to solve the problem of signal attenuation in advance, is conducive to the analysis of the injury. The latter through the vibration signal with wavelet packet decomposition for a number of bands, the use of before and after the injury frequency component of the energy changes in the characteristics injury analysis. The two methods can better analysis of the structural damage.

Related Dissertations

  1. Research on Vector Control System of Induction Motor Based on DSP,TM346
  2. Feature Extraction, Selection and Combination in Lipreading,TP391.41
  3. Over-voltage Identification of Transmission Line Based on Hilbert-Huang Transformation,TM866
  4. Research on Identification System of Cashmere and Wool Fiber,TS101.921
  5. Characteristics of sensory stimulation evoked,R318.0
  6. Network transmission ROI image coding algorithm,TN919.81
  7. Image Fusion Algorithms Based on Multi-scale Analysis,TP391.41
  8. The magnetorheological damper mechanical properties and Gun Recoil,TB535.1
  9. An Algorithm on Clustering and Anomaly Detection for Multiple Data Streams,TP311.13
  10. Research on Information Hiding Based on Images,TP309.7
  11. Research Implementation of Crack Detection Method Based on Its Acoustic Property,TP274
  12. Combined DWT Dynamic Data Reconciliation Research and Application,TP274
  13. The Compression and Application of the Brain CT Image,TP391.41
  14. The Realization and Study of a Scalable Data Encoder Based on SPIHT,TN762
  15. Research and Implementation of Dwt-based Video Codec System at Low Bit Rates,TN919.81
  16. Improved ROI Coding Method Based on SPIHT,TN919.81
  17. Two Algorithms for Image Processing Based on Chaos and Fractal,TP391.41
  18. The Research of Phishing Detection Technology Based on Nearest Neighbor and Similarity Measurement,TP393.08
  19. Study of Ultrasonic Location for Partial Discharge in Transformer,TM855
  20. Study on Excitation and Speed Control System Modeling and Visualization Parameter Identification Software,TM743
  21. Based on non- parametric statistical characteristic quantities Gaussian kernel network traffic anomaly detection method,TP393.07

CLC: > Industrial Technology > Building Science > Building structure > Structure theory to calculate > Structural Mechanics > Structural Dynamics
© 2012 www.DissertationTopic.Net  Mobile