High resolution modal analysis

The Fourier‐transform‐based traditional modal analysis techniques perform poorly when modal overlap η exceeds 30%, due to the ΔT.Δf limitation. In view of filling the gap between the low‐ and the high‐frequency domains where modal analysis and statistical methods respectively apply, a technique based on the high resolution analysis algorithm ESPRIT (Roy & Kailath, IEEE Transactions on Acoustics Speech and Signal Processing, 37(7), 984‐995, 1989) has been developed. A pulselike force is repeatedly applied to the structure and the response is measured in a number of points. In each point, the impulse response of the structure is retrieved by deconvolving the pulselike force and filtering the response with the result. In a second step, the number of modes in the reconstructed impulse response is evaluated by the novel procedure ESTER (Badeau et al., IEEE Transactions on Signal Processing, 54(2), 450‐458, 2006) and various preconditioning techniques are applied. The ESPRIT algorithm finally extracts the modal...