A method for testing plate thickness

Abstract

The invention discloses a method for testing plate thickness. In the stress wave excited by the initial excitation, compression wave, shear wave and Rayleigh wave propagating to the surroundings will be generated. The Rayleigh wave occupies most of the energy, and the shear wave times In other words, the energy carried by the compression wave is the smallest. Each wave takes the excitation point as the center of the circle and propagates to the surrounding process at different speeds. The energy will attenuate, but the attenuation rate is the slowest for the Rayleigh wave. Because the compression wave is reflected by the bottom of the plate The back-echo signal has very little energy and is affected by the excitation signal. The present invention proposes a method for separating the excitation signal from the echo signal in the time domain. In order to avoid the impact of different compression wave velocities of different concrete slabs on the test results due to factors such as different mix ratios, strengths, and ages, and to avoid the impact of different slab sizes and compression wave wavelengths on the test results caused by different compression wave velocities, In order to reduce the error of the detection result, the present invention proposes a method for measuring plate thickness which is independent of the compression wave velocity of the plate.

Description

technical field [0001] The invention relates to the technical field of concrete slab thickness testing, in particular to a method for testing slab thickness. Background technique [0002] Concrete slabs, slabs made of reinforced concrete materials, are basic components in building construction and various engineering structures. They are often used as roofs, floors, platforms, walls, retaining walls, foundations, floors, roads, pools, etc. , The application range is extremely wide. Reinforced concrete slabs are divided into square slabs, circular slabs and special-shaped slabs according to the plane shape, and are divided into one-way slabs and two-way slabs according to the stress action mode of the structure. Slabs and beamless slabs supported by columns, concrete slabs need to be inspected for thickness before completion and acceptance of the project. [0003] For structures such as concrete slabs, whose thickness is relatively thin, the excitation signal and the echo si...

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Problems solved by technology

[0005] The invention solves the problem of concrete slabs and other structures, whose thickness is relatively thin, and the excitation signal and the echo signal of the acoustic echo method are often intertwined together, which cannot be separated in the time domain. The echo signal is separated by means of frequency spectrum analysis such as FFT, However, the effect is generally not very ideal, and the compression wave velocity of concrete should be preset according to experience, but the wave velocity of different concrete is not a fixed value, which causes a large error

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