Acoustic excitation non-contact modal testing system and method

Abstract

The invention belongs to the field of mechanical measurement and provides an acoustic excitation non-contact modal testing system and method. The problem that the conventional modal testing result for a thin-slab structure is inaccurate is solved in a non-contact modal testing mode. According to the technical scheme, the method comprises the following steps: giving a sound by using a loudspeaker, generating vibration through a non-contact excitation thin-slab testing piece, measuring an acoustic signal by using an acoustic sensor, and measuring the vibration response of the thin-slab testing piece by using a scanning-type laser vibration measurement system in a laser non-contact way; by taking the acoustic signal measured by the acoustic sensor as an input signal and taking the vibration response measured by the scanning-type laser vibration measurement system as an output signal, performing analysis through conventional modal analysis software in the scanning-type laser vibration measurement system to obtain modal parameters of the thin-slab testing piece. The system and the method have the benefits that the influence on additional quality and additional rigidity is avoided in a modal test performed by using the system and the method, and the accurate modal parameters can be obtained; meanwhile, the structural damage to the testing piece is avoided, and the testing effect is good.

Description

technical field [0001] The invention belongs to the field of mechanical measurement, and in particular relates to an acoustic excitation non-contact modal test system and method. Background technique [0002] For thin-plate structures such as circuit boards, it is necessary to obtain the modal parameters of the structure during dynamic analysis. There are two ways to obtain the modal parameters. The first is theoretical calculation, usually finite element calculation; the other is through Modal test acquisition. For complex structures, theoretical calculations often have large deviations, which need to be corrected by modal tests, so modal tests are the basis for dynamic analysis of thin plate structures. [0003] Carrying out a modal test usually requires the use of a vibrator or a force hammer to excite the structure to be analyzed and measure the excitation force, stick a vibration sensor on the structure to measure the vibration response, and obtain the modal parameters...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide an acoustic excitation method especially suitable for thin-plate structures in view of the technical problems that there are additional mass and additional stiffness in the modal test of thin-plate structure dynamic analysis, which affect the accuracy of test results and easily cause damage to structural parts. Non-contact modal test system and method, using loudspeaker to emit sound to perform non-contact excitation on thin plate structure, using acoustic sensor to measure acoustic signal, and using laser to non-contact measure structural vibration response

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