Virtual crack close method based analog acoustic emission signal acquisition method

Abstract

The invention discloses a virtual crack close method based analog acoustic emission signal acquisition method. The method includes: analyzing a transfer function and a basic detection principle of an acoustic emission detection system to obtain a finite element analysis based metal component fatigue crack acoustic emission signal amplitude expression on the basis of an elastic wave propagation theory; on the basis of a virtual crack close method theory, a user unit subprogram function of ABAQUS software is adopted for developing an acoustic emission fatigue unit which can be used for acquiring fatigue crack analog acoustic emission signals of metal components; establishing a finite element model of the metal components in ABAQUS, and adopting the virtual crack close method based acoustic emission fatigue unit for acquiring the fatigue crack analog acoustic emission signals of the metal components under specific load action. The method has advantages that problems of long period, complex test steps and high cost in acquisition of the fatigue crack acoustic emission signals of the metal components through fatigue acoustic emission detection test are solved, and influences caused by different operation environment temperatures and impact loads are avoided.

Description

Technical field [0001] The invention relates to the field of fatigue damage detection of materials, and in particular to a method for obtaining a fatigue crack propagation simulation acoustic emission signal of a metal component under the condition of bearing a cyclic tensile load. Background technique [0002] At present, the common method to study the law of fatigue crack growth of metal components is to carry out fatigue tests and use non-destructive testing methods to assist in obtaining other parameters. However, due to the large number of load cycles (as few as hundreds of thousands of times, as many as several months), the fatigue test of metal structural materials requires a long time and a test requires a high expenditure. In addition, at present, finite element analysis can be used to directly obtain the fracture parameters, but the equipment cannot be used to directly measure the fracture mechanics parameters of metal components under cyclic loading. The fatigue eleme...

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Problems solved by technology

[0006] The object of the present invention is to provide a method for obtaining simulated acoustic emission signals based on the virtual crack closure method, so as to overcome the problems of long period, cumbersome test steps and high cost of obtaining fatigue crack acoustic emission signals of metal components through fatigue acoustic emission detection tests ; The present invention simultaneously avoids the influence of different working environment temperatures and impact loads

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