Modeling and Estimation of Spectral Stretching in Aluminum Beam Frequency Response Function Signals Using Experimental Modal Analysis and Adaptive Signal Processing

Document Type : Original Article

Authors
محمد خاکباز 1
Alireza Ebrahimi Hesari 2
Amin Darani goldarreh 3
Mehrdad Karimi 1
1 PhD student in Aerospace Engineering, Faculty of Graduate Studies, Shahid Sattari Aeronautical University of Sciences and Technology, Tehran, Iran
2 PhD student in Mechanical Engineering, Faculty of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
3 MSc student in Aerospace Engineering, Faculty of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
10.22034/stme.2025.535696.1151
Abstract
The high sensitivity of spectral strain estimation has made it a powerful tool for early detection of failures and dynamic nonlinear instabilities. In this study, first, the modal analysis of a free-free aluminum beam was addressed in the form of three experimental, analytical, and numerical approaches. In the modal section, the dynamic responses of the beam were recorded at six points with a calibrated hammer impact test. The experimental results were combined with signal analysis and advanced algorithms to obtain modal parameters, including natural frequencies, modal vectors, and frequency responses, with an accuracy of more than 90% compared to the analytical and numerical results. Numerical modeling in Abaqus showed that the results at frequencies of 80 to 1800 Hz corresponded with acceptable accuracy and were able to simulate the vibration behavior of the system with low error. In the second section, the analysis of dynamic signs and spectral strain of the frequency response function signal was performed using wavelet transform and short-time Fourier transform methods. The results of this analysis showed that at a frequency of 255 Hz, there is a significant dynamic anomaly in mode 2 with a high quality factor (more than 25) and a strain in the range of 4.5 to 6.5, indicating the possibility of cracks, loosening, or stiffness changes in the structure. This anomaly is stable over time and is associated with mode interaction and nonlinear phenomena.
Keywords
Modal analysis
aluminum beam
spectral kurtosis
frequency response function
dynamic anomaly
Subjects

اصل مقاله

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Science and Technology in Mechanical Engineering
Volume 4, Issue 2 - Serial Number 7
February 2026
Pages 219-240

  • Receive Date 20 July 2025
  • Revise Date 08 November 2025
  • Accept Date 15 November 2025
  • First Publish Date 15 November 2025
  • Publish Date 21 January 2026