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Method for predicting sheet forming fractures based on damage fracture standard numerical value

A numerical prediction and criterion technology, applied in the direction of electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as fracture errors

Active Publication Date: 2015-05-20
HUAZHONG UNIV OF SCI & TECH
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Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a method for numerically predicting the fracture of sheet metal forming based on the damage fracture criterion. technical problems, and at the same time, the damage and fracture criterion of the method of the present invention can be used to guide the improvement of sheet metal forming ability and the forming quality of parts, and has the characteristics of low cost and high efficiency

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  • Method for predicting sheet forming fractures based on damage fracture standard numerical value
  • Method for predicting sheet forming fractures based on damage fracture standard numerical value
  • Method for predicting sheet forming fractures based on damage fracture standard numerical value

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[0111] Illustrate method step of the present invention below by example:

[0112] (1) The stamping experiment of metal sheet cylindrical parts is carried out on a 1000kN servo press. The diameter of the metal sheet is 180mm and the thickness is 1mm. Y-direction compressive stress load f of circle 1y With the punch pressure f 2 changes with changes, that is, f 1y =0.3f 2 . The mold parting speed adopted is 10mm / s, and the friction coefficient in the stamping experiment of metal plate cylindrical parts is lubricated with engine oil and adjusted to 0.15. The radius is 8mm, and the inner diameter of the die used is 100mm. The material of the metal sheet used is aluminum alloy 5052-O with a density of 2700kg / m 3 , the elastic modulus E is 70GPa, and Poisson's ratio is 0.33. During the stamping process of sheet metal cylindrical parts, the sheet is subjected to four surface forces, and the balance differential equation of stress can be obtained as follows:

[0113] ...

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Abstract

The invention discloses a method for predicting sheet forming fractures based on a damage fracture standard numerical value. The method includes the steps of obtaining the stress state distribution of a metal sheet cylindrical piece in the stamping process according to the thermodynamics irreversible law, obtaining a stress balance differential equation of the metal sheet cylindrical piece in the stamping process according to the stress state distribution, calculating the change rate, occurring when the metal sheet cylindrical piece is damaged, of the area of a small unit of the metal sheet cylindrical piece in the stamping process according to the continuum damage mechanics theory, obtaining the damage to the metal sheet cylindrical piece according to the change rate, calculating the relation between the damage and the strain of the metal sheet cylindrical piece, and finally deriving the relation between the damage value and the true stress, true strain and hydraulic stress of the metal sheet cylindrical piece under the unidimensional scale in the whole stamping process. By means of the method, the technical problem that when fractures during sheet forming are predicted through an existing numerical value method, errors are large can be solved.

Description

technical field [0001] The invention belongs to the field of plastic forming, and more specifically relates to a method for numerically predicting sheet metal forming fracture based on a damage fracture criterion. Background technique [0002] Sheet metal forming is one of the very important processing methods of metal plastic forming, which occupies a considerable proportion in aerospace, automobile, shipbuilding and civil industries. In the past, the experience of sheet metal forming process was very rich, and the improvement of process and technology often came from dozens or even hundreds of repeated trials. With the complexity of processed parts and the sharp increase in workpiece output, the Fracture has always been a difficult and hot issue in the field of metal plastic forming. In the sheet metal forming process, not only the plastic flow of the material is included, but also the damage of the material is accompanied, and with the evolution of the material damage, i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50B21D22/02
Inventor 黄亮曾嵘李建军洪秀东张琦
Owner HUAZHONG UNIV OF SCI & TECH
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