Method of identifying cause of springback and apparatus of identifying cause of springback

Patent metadata

Field	Value
Publication number	US-10012555-B2
Application number	US-201314406945-A
Country	US
Kind code	B2
Filing date	Aug 15, 2013
Priority date	Sep 26, 2012
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A method of identifying a cause of springback includes a step of performing a press forming analysis, a step of performing a springback analysis on the basis of information acquired by the press forming analysis, a step of dividing a shape of a press forming product acquired by the press forming analysis into a plurality of regions, a step of changing Young's modulus in a designated direction in any region of the divided regions, a step of performing the springback analysis on the press forming product whose Young's modulus is changed, a step of acquiring springback amount differences on the basis of multiple springback analysis results, and a step of identifying the cause of the springback on the basis of the acquired springback amount differences.

First claim

The invention claimed is:

1. A method of identifying a cause of springback of a press forming product, the method comprising:
a press forming analysis step of acquiring a shape, a residual stress distribution, and a strain distribution of the press forming product before the press forming product is released from a die;
a first springback analysis step of acquiring a springback amount of the press forming product after the press forming product is released from the die, the first springback analysis being based on the shape, the residual stress distribution, and the strain distribution of the press forming product;
a region dividing step of dividing the shape of the press forming product into a plurality of regions;
a Young's modulus changing step of selecting a first region of the plurality of regions and changing the Young's modulus and a designated direction of the first region;
a second springback analysis step of acquiring the springback amount of the press forming product for each of the plurality of regions including the first region, the second springback analysis being performed after the press forming product is released from the die for each region for each designated direction changed in the Young's modulus changing step with regard to the plurality of regions including the first region and after the Young's modulus changing step, the second springback analysis step being based on the shape, the residual stress distribution, and the strain distribution of the press forming product;
a springback amount difference acquisition step of acquiring springback amount differences for each region for each designated direction by comparing the springback amount acquired at the first springback analysis step with each springback amount for each region for each designated direction acquired at the second springback analysis step; and
a springback cause identifying step of comparing the springback amount differences with each other for all of the plurality of regions and the designated directions, and, based on the comparison, identifying a region of the plurality of regions and a direction as having caused the springback, the identified region and the direction having a maximum springback amount difference,
wherein, when a relation between a stress σ and a strain ε is expressed by ε=Cσ and where E xx is the Young's modulus in an x direction, E yy is the Young's modulus in a y direction, and E zz the Young's modulus in a z direction at the Young's modulus changing step and the second springback analysis step, an elastic compliance C is given by the following formula (1):

C
=

[

1

E
xx

-

v
yx

E
yy

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zx

E
zz

0

0

0

-

v
xy

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xx

1

E
yy

-

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zy

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Assignees

• Jfe Steel Corp

Inventors

• Sumikawa Satoshi
• Ishiwatari Akinobu

Classifications

• G01L5/00 Primary

  Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes · CPC title

• Y02T10/82

  Elements for improving aerodynamics · CPC title

• G06F30/23

  using finite element methods [FEM] or finite difference methods [FDM] · CPC title

• B21D22/00 Primary

  Shaping without cutting, by stamping, spinning, or deep-drawing (otherwise than using rigid devices or tools or yieldable or resilient pads B21D26/00) · CPC title

• G06F17/5018

  Physics · mapped topic