Determination method for failure parameters of materials with complex defects

A technology for complex defects and material failure, applied in the direction of applying stable tension/pressure to test material strength, etc., can solve problems such as no method, and achieve the effect of simple measurement, high measurement accuracy, and wide application of defect objects

Inactive Publication Date: 2015-03-04
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] In addition, for experimental measurements of material failure parameters, and critical values ​​for materials Π C The experimental calibration, so far there is no effective method

Method used

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  • Determination method for failure parameters of materials with complex defects
  • Determination method for failure parameters of materials with complex defects
  • Determination method for failure parameters of materials with complex defects

Examples

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Embodiment Construction

[0034] Below in conjunction with a plexiglass plate contains circular hole defect example, the inventive method is described in further detail:

[0035] (1) The test piece in the example is as figure 1 As shown, a hole is punched with the geometric center of the specimen as the center. Among them, the thickness of the test piece is 2mm, and the hole diameters are 2mm, 4mm, 5mm, and 6mm respectively, and a total of 4 ( image 3 ). The elastic modulus of organic glass material is 3.0GPa, and the linear elastic Poisson's ratio is 0.35.

[0036] (2) The surface of the material specimen is polished, and then the surface of each specimen is sprayed with two types of anti-reflective paint with large color difference (such as black and white) to form a speckle state with high contrast, fine particles, and random distribution , which is convenient for the identification and calculation analysis of the lens, and the speckle pattern of the specimen is as follows figure 2 shown.

[...

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Abstract

The invention discloses a determination method for failure parameters of materials with complex defects. The determination method comprises the following steps: firstly, preparing material test pieces, then carrying out polishing treatment on the surfaces of the test pieces, and spraying reflection-eliminating paint with two color differences to the surface of each test piece till the surface of each test piece is in a speckle state; then carrying out tensile loading on the two ends of each test piece by utilizing a mechanical testing machine till the test piece is completely broken; then carrying out image recording on the loading process by using 3D-DIC optical measuring equipment, thereby obtaining displacement-field distribution of the whole-process loading of each test piece; selecting a closed integration path enclosing all the defects, and obtaining a value of M integration by utilizing a definition formula of the M integration; and finally, calculating the failure parameters of samples, wherein Pi is equal to ME/(Sigma<2>A<D>), the failure rule of the complex defects of the materials is defined as that Pi is more than or equal to Pi<C>, and when the calculated Pi parameter reaches to the critical value Pi<C>, the defects start to be unstable and extend.

Description

technical field [0001] The present invention relates to a method for describing the final failure state of complex defect materials. Background technique [0002] For materials with complex defects, on the one hand, the calculation of crack tip control parameters such as energy release rate, stress intensity factor, and J-integral criterion in fracture mechanics requires a clear and measurable macroscopic crack length and shape. group, it is difficult to obtain a clear main crack morphology. And with the development of modern engineering materials, strong heterogeneous materials such as porous metal foam materials, nanoporous thin film materials, and ferroelectric polycrystalline materials have been widely used. These materials often contain complex defects, and the interference shielding effect between the defects is also very complex, making it difficult to accurately predict and predict the evolution mode and evolution results of the internal defects of the material unde...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/08
Inventor 李群郭宇立
Owner XI AN JIAOTONG UNIV
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