A broadband surface wave exciter

Abstract

The invention provides a wide-band surface wave exciter, which includes: a surface wave excitation device, an electric power amplitude-changing signal source device, and a power supply, wherein the surface wave excitation device includes a magnetic excitation unit, an electric An excitation unit and a vibration emission unit, the magnetic excitation unit and the electric excitation unit are respectively connected to the vibration emission unit. The wide-band surface wave exciter of the invention has simple structure and perfect effect, provides an excitation source with wide applicability for surface wave nondestructive testing of concrete structures, and improves the resolution and precision of surface wave nondestructive testing.

Description

technical field [0001] The invention relates to a surface wave non-destructive testing instrument for concrete structure engineering, in particular to a wide-band surface wave exciter capable of sending out wide-band variable-amplitude steady-state surface wave signals. Background technique [0002] Surface wave is a kind of elastic wave that propagates along the surface of solid medium. It has two remarkable characteristics. One is that its propagation speed is similar to that of shear wave; the other is that it has dispersion characteristics in layered media. Using the former characteristic, the elastic modulus of the medium can be calculated by testing the propagation velocity of the surface wave, so as to evaluate the mechanical properties of the medium; using the latter characteristic, the dispersion curve of the surface wave (velocity versus frequency or wavelength) Change curve), the thickness and wave velocity of each layer can be calculated, and then the change of t...

AI Technical Summary

Problems solved by technology

[0004] The above test method has the following defects: 1. The transient surface wave excitation source is generated by striking the surface of the medium with a hammer. The vibration generated by each strike has only one dominant frequency, and the frequency range of the surface wave generated by the strike is difficult to control

Therefore, there are defects such as low upper frequency limit and easy misjudgment of phase contrast during constant amplitude vibration when the electromagnetic exciter generates steady-state surface waves.

[0006] It can be seen that there are defects in the prior art that the frequency range of the measuring instrument is small, the measurement accuracy is low, the structure is complicated, and the accuracy is not high, and further improvement is urgently needed

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