Method for obtaining elastic property of isotropous sheet material based on simplex method

A technique for isotropic, thin-sheet materials used in processing probe response signals, analyzing solids using acoustic/ultrasonic/infrasonic waves, etc.

Active Publication Date: 2014-07-16
BEIJING UNIV OF TECH
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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of wave velocity extraction o

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  • Method for obtaining elastic property of isotropous sheet material based on simplex method
  • Method for obtaining elastic property of isotropous sheet material based on simplex method
  • Method for obtaining elastic property of isotropous sheet material based on simplex method

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Embodiment Construction

[0037] Below in conjunction with specific example, content of the present invention is described in further detail:

[0038] Step 1 Establish the simulation objective function

[0039] The dispersion relation is obtained by linearly combining the partial waves inside the isotropic material specimen and defining it in a characteristic equation about the boundary conditions. A plate with a thickness of 2h puts it in the Cartesian coordinate system, such as figure 1 As shown, the x1-x3 plane is the sagittal plane of Lamb wave propagation, and the coordinate x1 represents the propagation direction of the wave. The global coordinates (x1,x2,x3) serve the following theory.

[0040] Step 1.1 According to the equation of motion: (Gravity ρf can be ignored j influence); and the constitutive equation: σ ij = c ijkl ε kl ;Geometric equation: Inferring the Propagation Equation of the Control Wave c ijkl · u ...

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Abstract

The invention discloses a method for obtaining the elastic property of an isotropous sheet material based on a simplex method and belongs to the field of ultrasonic guided-wave nondestructive testing and evaluation. Based on an acoustic microscope technology and according to a self-developed ultrasonic system for measuring the elastic coefficient of a material, a line focusing polyvinylidene fluoride (PVDF) probe is adopted, the velocity of longitudinal waves and surface waves is simultaneously measured, and nondestructive testing of the elastic coefficient of the material can be realized. According to a novel inverse algorithm, the elastic property of the sheet material is obtained by virtue of the line focusing probe. According to the method, an objective function is induced into a coefficient matrix determinant of a frequency dispersion characteristic equation based on the simplex method, and the elastic property and the sample density can be obtained through acoustical properties and the measured density. The method can be used for extracting the wave velocity of the isotropous sheet material and is an advanced material wave velocity extraction method.

Description

technical field [0001] The invention relates to a method for obtaining the elastic coefficient of a coating material based on a simplex method, and belongs to the field of ultrasonic guided wave nondestructive testing and evaluation. Background technique [0002] With the development of material science, various new materials are constantly emerging, and many materials show extraordinary mechanical properties. Therefore, the testing of mechanical properties of materials is an important part of material science. Studies have shown that the elastic coefficient of the material is closely related to the material preparation process. Using ultrasound to measure the elastic properties of materials is one of the promising measurement methods in the field of non-destructive testing. In an isotropic homogeneous thin plate material, the propagation of ultrasonic waves has a dispersion characteristic, and this characteristic contains a large amount of information about the mechanical ...

Claims

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Application Information

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IPC IPC(8): G01N29/04G01N29/46
Inventor 宋国荣刘宏实吕炎李子木何存富吴斌
Owner BEIJING UNIV OF TECH
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