Method for detecting wave velocity, material state and damage degree based on stress wave field

Abstract

The application discloses a method of detecting wave speed, material status and damage degree on the basis of stress wave field. The method includes the steps of: 1) manufacturing transmission grid lines, and enabling a direct current light source to pass through the transmission grid lines and be projected on the surface of a test piece to form static reflective stripes, which is then received by a high-speed camera after full-reflection; 2) applying excitation on the test piece, so that the reflective stripes are displaced by means of stress wave generated by the excitation, and collecting the change of the reflective stripes on time series by the high-speed camera for carrying out subtracting analysis to a reflective stripe image, thus obtaining the evolution rule of deformation field with time; 4) calculating the wave speed of the stress wave in the test piece material in a manner of multi-point measurement to calculate average value; and 5) recognizing the positions and sizes of defects in the test piece, and performing inversion to obtain residual stress distribution in the test piece in stress propagation direction. The method is used for detecting wave speed of a two-dimensional stress wave, the material status and the damage degree in a completely-non-contacted manner. The method has high sensitivity, simple operations and achieves visualization of wave field propagation law of the stress wave.

Description

technical field

[0001] This application relates to the fields of optical measurement experiment mechanics and non-destructive testing, and specifically relates to a method for detecting wave velocity, material state and damage degree based on stress wave field. Background technique

[0002] When the object is under the action of impact load, stress waves will be generated inside the object. The study of the propagation process and law of stress wave is of great significance to the study of the impact load on the object. The propagation velocity of the stress wave inside the object is an important basic quantity. The measured propagation velocity of the stress wave is not only beneficial to the study of the propagation process and law of the stress wave, but also can calculate the dynamic physical parameters of the material. Usually, the method of measuring the propagation velocity of stress wave is to use electrical measurement method, which often brings inestimable errors t...

Examples

Embodiment

[0034] Such as figure 1 Described is a method for detecting stress wave velocity based on two-dimensional stress wave field characteristics described in the implementation example of this application. The specific operation steps are:

[0035] Step 101, using the laser marking machine to optimize the parameters of the grid to make a transmission grid line, direct current strong light is irradiated through the grid line to form static reflection stripes on the surface of the test piece, and after total reflection on the surface of the test piece, the Static reflection stripes are captured by a high-speed camera;

[0036]In this embodiment, the laser marking machine optimization parameter grid method is used to make the transmission grid line, the scanning power of the laser marking machine is increased, and the scanning is performed on an aluminum sheet with a thickness of 0.1 mm. The scanning pattern is 20 parallel rectangles. The length is 20mm, the width is 1.5mm, and the s...

technical field

[0001] This application relates to the fields of optical measurement experiment mechanics and non-destructive testing, and specifically relates to a method for detecting wave velocity, material state and damage degree based on stress wave field. Background technique

[0002] When the object is under the action of impact load, stress waves will be generated inside the object. The study of the propagation process and law of stress wave is of great significance to the study of the impact load on the object. The propagation velocity of the stress wave inside the object is an important basic quantity. The measured propagation velocity of the stress wave is not only beneficial to the study of the propagation process and law of the stress wave, but also can calculate the dynamic physical parameters of the material. Usually, the method of measuring the propagation velocity of stress wave is to use electrical measurement method, which often brings inestimable errors t...

Examples

Embodiment

[0034] Such as figure 1 Described is a method for detecting stress wave velocity based on two-dimensional stress wave field characteristics described in the implementation example of this application. The specific operation steps are:

[0035] Step 101, using the laser marking machine to optimize the parameters of the grid to make a transmission grid line, direct current strong light is irradiated through the grid line to form static reflection stripes on the surface of the test piece, and after total reflection on the surface of the test piece, the Static reflection stripes are captured by a high-speed camera;

[0036]In this embodiment, the laser marking machine optimization parameter grid method is used to make the transmission grid line, the scanning power of the laser marking machine is increased, and the scanning is performed on an aluminum sheet with a thickness of 0.1 mm. The scanning pattern is 20 parallel rectangles. The length is 20mm, the width is 1.5mm, and the s...

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