Closely spaced mode damping ratio precisely-diagnosing method

Abstract

The invention discloses a closely spaced mode damping ratio precisely-diagnosing method. The method comprises constructing a standard orthogonal system through a Schmidt orthogonalization calculation method according to the number of orders of closely spaced modes and then performing inner product operation on closely spaced mode signals and the standard orthogonal system; obtaining the attenuation coefficient and the inherent frequency of every order of the closely spaced mode signals according to the Bessel inequation theorem when the closely spaced mode signals have the maximum projection in the standard orthogonal system, namely, when inner product modular square sum is maximized, wherein the maximum value of the inner product modular square sum is obtained through optimizing search of the genetic algorithm and the Newton method; obtain the damping ratio of every order of the mode through the relation of the attenuation coefficient, the inherent frequency and the damping ratio. According to the closely spaced mode damping ratio precisely-diagnosing method, the diagnosing process only requires a limited section of signals, identification is performed by performing the inner product operation on the closely spaced mode signals and the constructed standard orthogonal system, accordingly the limit of the number of orders of the modes and the size of the damping value can be avoided, and the diagnosing results are accurate; besides, the closely spaced mode damping ratio precisely-diagnosing method is also applicable to the damping identification of non-closely spaced mode signals.

Description

technical field [0001] The invention relates to the related fields of vibration signal processing, in particular to a method for accurately diagnosing the dense modal damping ratio. Background technique [0002] Damping (or damping ratio) is one of the important characteristic parameters in terms of vibration reduction and noise reduction. It is also of great significance in structural dynamics research such as structural fault diagnosis, safety assessment, structural design, and real-time vibration monitoring. The diagnostic accuracy of damping is much lower than that of natural frequency and mode shape. If the damping value can be accurately identified, it can be used as a commonly used important parameter to solve practical engineering problems in structural fault diagnosis, vibration control and noise reduction. The diagnostic accuracy of damping has been a challenge. [0003] In the field of vibration signal processing engineering, the dense mode signal is a common sig...

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Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem of inaccurate identification of dense modal damping existing in the prior art. Based on the Bessel inequality theorem, a method for accurately diagnosing the dense modal damping ratio is proposed to solve the problem of dense modal damping. Damping ratio diagnosis problem, and the method is also suitable for damping identification of non-dense modal signals

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