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Stress-strain relationship simulation method, spring back prediction method, and spring back analyzing device

A technology of strain relationship and simulation method, applied in the direction of measuring device, using stable tension/pressure to test the strength of materials, analyzing materials, etc. Different gradients, etc.

Active Publication Date: 2015-12-02
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0013] However, in the method described in Patent Document 1, if the stress-strain relationship under unloading (compression) and re-stretching deformation is calculated, the gradient of stress with respect to strain is different in unloading and re-stretching, and it is impossible to draw Using experimentally obtained point symmetric hysteresis
In other words, in the method of Patent Document 1, the stress-strain relationship in the case where the material is subjected to reverse stress cannot be simulated with high accuracy

Method used

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  • Stress-strain relationship simulation method, spring back prediction method, and spring back analyzing device
  • Stress-strain relationship simulation method, spring back prediction method, and spring back analyzing device
  • Stress-strain relationship simulation method, spring back prediction method, and spring back analyzing device

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Experimental program
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Embodiment approach 1

[0144] 〔Stress-strain relationship simulation method〕

[0145] Next, refer to Figure 7 A stress-strain relationship simulation method according to one embodiment of the present invention will be described. Figure 7 It is a flowchart showing the flow of the stress-strain relationship simulation method according to the first embodiment. In the process of step S1, the operator acquires experimental values ​​of the stress-strain relationship of the elastoplastic material. In order to obtain the experimental value, the operator conducts the following test: unloading the elastoplastic material after applying stress in the tensile direction to plastically deform it, and applying stress in the compressive direction to plastically deform it (tension→unloading→compression). In addition, the operator conducted a test of unloading after applying stress in the tensile direction to plastically deform it, and applying stress in the tensile direction again to plastically deform it (stretc...

Embodiment approach 2

[0152] 〔Prediction method of springback amount〕

[0153] Next, refer to Figure 8 A rebound amount prediction method according to one embodiment of the present invention will be described. Figure 8 It is a flowchart showing the flow of the rebound amount prediction method of this embodiment. The processing of steps S1 to S4 is the same as Figure 7 are the same, so their description is omitted. In the processing of step S6, if the material constants determined by the processing of steps S2 to S4 are substituted into the elastoplastic constitutive equations (1) (2), the computer uses the elastoplastic constitutive equations substituted into the material constants to execute the return Spring analysis, predict the amount of springback.

Embodiment approach 3

[0155] By including the dynamic hardening increment vector dα created in Embodiment 1 ij The elastoplastic constitutive equation is loaded into the finite element method (finiteelementmethod) analysis software to form a springback analysis device. Below, based on Figure 9 The shown block diagram illustrates the structure of such a springback analysis device 1 .

[0156] [Rebound analysis device]

[0157] Such as Figure 9As shown, the rebound analysis device 1 is composed of a PC (personal computer), etc., and has a display device (display device) 3, an input device (input device) 5, a main storage device (memory storage) 7, an auxiliary storage device 9, and arithmetic processing (arithmetic processing). ) Section 11. A display device 3 , an input device 5 , a main storage device 7 , and an auxiliary storage device 9 are connected to the arithmetic processing unit 11 , and each function is executed in accordance with an instruction from the arithmetic processing unit 11 ...

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Abstract

This method acquires an experimental value for a stress-strain relationship by plastically deforming an elastic-plastic material by displacing or applying a load on same. A calculator: identifies, by using the acquired experimental value, a material parameter contained in an elastic-plastic constitutive model as a prescribed first formula expressing a kinematic hardening incremental vector (dαij) for a yield surface in the elastic-plastic constitutive model that is defined as the function for stress and back stress; identifies a material parameter contained in a prescribed second formula on the basis of the prescribed first formula into which the identified material parameter is substituted and the acquired experimental value; and simulates the stress-strain relationship of the elastic-plastic material by using the prescribed first formula and the prescribed second formula, into which the identified material parameters are substituted, and the elastic-plastic constitutive model.

Description

technical field [0001] The present invention relates to a stress-strain relationship simulation method for evaluating the stress-strain relationship of an elastic-plastic material, and a springback amount for predicting the springback amount of an elastic-plastic material during press molding Prediction method and springback analysis device for stamped products. Background technique [0002] Press forming (press forming) is a method of processing a blank (blank) (metal plate) to be formed by pressing a die to transfer the shape of the die to the blank. In this press forming, so-called springback occurs in which the deformation applied to the blank is slightly recovered after the press-formed product is taken out from the die, and the press-formed product may differ from the desired shape. Therefore, in press forming, it is necessary to predict the amount of springback of the press-formed product, and to design the shape of the die based on the prediction result so that the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/00B21D5/01B21D22/00
CPCG01N33/442B21D22/00G01N3/08G01N2203/0075G01N2203/0092G06F30/20G06F17/16
Inventor 澄川智史石渡亮伸
Owner JFE STEEL CORP
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