Test modal analysis method based on base reduction method

Abstract

An experimental modal analysis method based on the reduced-basis method comprises the following steps: (1), organizing the preparation for experimental model analysis; (2), collecting dynamic signals, and utilizing LabVIEW imaging software to preprocess the signals in order to obtain a frequency response input-output transfer function matrix; (3), realizing the reduced-basis method in a LabVIEW-embedded Matlab program in order to obtain modal parameters including extreme points and modal participation factors; (4), setting up a stabilization diagram and evaluating the mode of vibration; (5), verifying the mode and comparing the result with other arithmetic methods, correcting the parameters of the reduced-basis method to re-calculate the modal parameters in the case that the result comparison is inconsistent with the requirement, and proceeding to the next step in the case that the result comparison is consistent with the requirement; and (6), making the animation of the mode and finalizing the design of the system. In order to scale down the degree of freedom, the invention projects a large-scale matrix to a small-scale matrix, thereby greatly accelerating calculation reducing experiment intensity and time, greatly improving experimental efficiency and greatly enhancing experiment accuracy.

Description

technical field [0001] The present invention mainly relates to the field of test modal analysis methods, and in particular refers to a test modal analysis method based on the subtraction method, which is mainly applied to large or extra-large measured objects such as automobiles, airplanes, submarines, and large building bridges. Experimental modal analysis. Background technique [0002] The process of test modal analysis consists of three parts: test preparation process, digital signal acquisition and processing, and modal parameter identification. The experimental preparation process includes the installation of the experimental platform, the hoisting of the experimental product, the drawing of the geometric size of the experimental product, the selection of the sensor layout, the installation and debugging of the sensor, etc. The work at this stage is how to use the results of finite element theoretical modal analysis (if there is no theoretical analysis result, it is ne...

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Problems solved by technology

[0005] However, there are three disadvantages in the above method: first, the iterative convergence speed is low, especially when the feature pairs of the reduced-order model are close to the exact value, the convergence speed is extremely low; second, the convergence of the iterative format is very difficult to prove , so so far there is no research in this area reported in the literature; the third is that the amount of calculation is still relatively large, especially when the number of master degrees of freedom is large

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