Method for establishing and using forming limit diagram of metal sheet material

A forming limit diagram, metal sheet technology, applied in the evaluation of the formability of magnesium (aluminum) alloy sheet in the heat treatment assisted forming process, the field of establishment of metal sheet forming limit diagram

Inactive Publication Date: 2012-09-12
TONGJI UNIV
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Problems solved by technology

[0007] The problem to be solved by the present invention is to provide a method for establishing the forming limit diagram of metal sheet, which can not only solve the problem of traditional forming limit diagram and formability evaluation, but also can be used to judge the process of heat treatment assisted forming of magnesium (aluminum) alloy sheet necking or cracking, and then evaluate the formability of magnesium (aluminum) alloy sheets in the heat treatment assisted forming process, and overcome the defects of traditional forming limit diagrams

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  • Method for establishing and using forming limit diagram of metal sheet material
  • Method for establishing and using forming limit diagram of metal sheet material
  • Method for establishing and using forming limit diagram of metal sheet material

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Embodiment Construction

[0025] Firstly, the specific steps of the present invention to establish the sheet metal forming limit diagram are described.

[0026] A. If figure 1 As shown, the XY coordinate system is established, and the X coordinate represents the strain ratio ρ ε , the Y coordinate represents the equivalent strain ε eq ;

[0027] B. Set the strain ratio ρ ε different values ​​of , and calculate the corresponding principal strain ε according to different strain ratios 1 , and then calculate the corresponding secondary strain ε 2 , according to the strain formula launch ε 2 = ρ ε ε 1 get the secondary strain,

[0028] The principal strain ε 1 The specific calculation method is:

[0029] -0.5≤ρ ε ≤0, ϵ 1 = n 1 + ρ ϵ - - - ( 1 )

[003...

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Abstract

The invention discloses a method for establishing and using a forming limit diagram of a metal sheet material. The method comprises the following steps of: A, establishing an XY coordinate system, wherein an X coordinate represents a strain ratio and a Y coordinate represents an equivalent strain; B, setting different values of the strain ratio, and calculating corresponding main strain and secondary strain according to the different strain ratios; C, calculating limit equivalent strain values at the different strain ratios through a formula according to the main strain and the secondary strain obtained in the step B; and D, marking the limit equivalent strain value corresponding to each strain ratio, which is obtained in the step C, on the XY coordinate system, and connecting marked points to be a curve, namely the forming limit curve shown by the limit equivalent strain values, wherein the XY coordinate system and the forming limit curve form the forming limit diagram of the metal sheet material. According to the method disclosed by the invention, the equivalent strains are used as variable values. Each equivalent strain is the single variable value, so that the influences of deformation in a pre-forming process on deformation stored energy and a forming limit of a magnesium alloy sheet material after thermomechanical treatment can be reflected in a more direct manner.

Description

technical field [0001] The invention relates to the field of sheet metal forming processing, in particular to a method for establishing and using a sheet metal forming limit diagram, which is mainly used for judging necking or cracking in sheet metal forming, and evaluating the formability of sheet metal, especially evaluating magnesium ( Formability of Al) alloy sheets during heat treatment assisted forming. Background technique [0002] Forming limit diagram is an important means to evaluate the formability of sheet metal. It is used to judge the necking or cracking of sheet metal during the forming process. It is especially important in the practical application of sheet metal forming technology. [0003] Magnesium (aluminum) alloy sheet is one of the important lightweight materials for automobiles. Due to the poor formability of magnesium (aluminum) alloy sheets at room temperature, a heat treatment-assisted forming process is used to form automotive panels with complex...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/28
Inventor 闵峻英林建平李芳芳庞政
Owner TONGJI UNIV
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