Method of identification of cause and/or location of cause of occurrence of springback

a technology of occurrence and location, applied in the field of method of identification of cause and/or location of occurrence of springback, can solve the problems of nonlinear problem, difficult analysis, and difficulty in designing tooling to fully consider springback by numerical analysis shorten the time for identification of location, and shorten the time for study

Inactive Publication Date: 2018-03-15
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This approach enables accurate identification and reduction of springback, reducing development time and costs by allowing for precise adjustments to forming conditions without compromising product strength or rigidity.

Problems solved by technology

Changes in conceptual design in the conceptual design stage cause changes in the formed members at the mechanical design stage, so the work and cost in the mechanical design stage of studying the method of forming the formed members become greater problems in the development process or development costs of automobiles etc.
However, designing tooling completely considering springback by numerical analysis is a nonlinear problem and extremely difficult, so the proposed method forms tooling simply considering springback by the finite element method.
Therefore, what measure becomes necessary when the allowable amount of springback cannot be met due to such tooling is difficult to analyze numerically, so no method of solution has been proposed up to now.
However, while the measures against the location of occurrence of springback reduce the residual stress causing springback, cutting out parts, forming holes, etc. cause the rigidity of the member itself to fall, so the problem arises that springback ends up occurring due to slight residual stress.
Furthermore, this sort of measure in practice requires actual tests by test tooling and steel sheet, so the problem arises of an increase in work and cost in the mechanical design stage.

Method used

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  • Method of identification of cause and/or location of cause of occurrence of springback
  • Method of identification of cause and/or location of cause of occurrence of springback
  • Method of identification of cause and/or location of cause of occurrence of springback

Examples

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example 1

[0289]Examples will be used to explain the present invention in more detail.

[0290]FIG. 19 gives views showing a part of a hat-formed cross-section covered by the springback analysis according to an embodiment of the present invention, wherein (a) is a perspective view and (b) is a cross-sectional view of the same. This is comprised of a web W0, side walls W1 and W2, and flanges F1 and F2.

[0291]For the numerical analysis performed by the press forming analyzer 11 and springback analyzer 12, the existing plating forming simulation analysis software PAM-STAMP based on the finite element method was used. For the springback analysis, elastic analysis by the static implicit method was used.

[0292]The forming conditions used were data of high strength steel sheet having, as properties of the metal plate, a sheet thickness of 1.6 mm and a tensile strength of the 780 MPa class. Further, the form of the tooling (die, punch, holder) was modeled by shell elements and analyzed assuming a rigid bo...

example 2

[0319]FIG. 36 gives views showing a part of a hat-formed cross-section covered by springback analysis according to an embodiment of the present invention, wherein (a) is a perspective view and (b) is a cross-sectional view of the same. The hat formed cross-section is a symmetric left-right form. The width of the punch used was made 80 mm, the forming height was made 80 mm, and the width of the workpiece was made 100 mm.

[0320]For the numerical analysis performed by the press forming analyzer 11 and springback analyzer 12, the existing plate forming simulation analysis software PAM-STAMP based on the finite element method was used. For the springback analysis, elastic analysis based on the static implicit method was used.

[0321]The forming conditions used were data of high strength steel sheet having, as properties of the metal plate, a sheet thickness of 1.6 mm and a tensile strength of the 780 MPa class. Further, considering the hat cross-section symmetrical form, the analysis was co...

example 3

[0331]FIG. 39 gives views showing a part of a hat-formed cross-section covered by springback analysis according to an embodiment of the present invention, wherein (a) is a perspective view and (b) is a cross-sectional view of the same. This is comprised of a web WO, side walls W1, W2, and flanges F1, F2.

[0332]For the numerical analysis performed by the press forming analyzer 11 and springback analyzer 12, the existing plating forming simulation analysis software PAM-STAMP based on the finite element method was used. For the springback analysis, elastic analysis based on the static implicit method was used.

[0333]The forming conditions used were data of high strength steel sheet having, as properties of the metal plate, a sheet thickness of 1.6 mm and a tensile strength of the 780 MPa class. Further, the form of the tooling (die, punch, holder) was modeled by shell elements and analyzed assuming a rigid body. The clearance between the die and punch was made the same as the sheet thick...

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Abstract

An apparatus for identification of a cause of occurrence of springback having a press forming analyzer for numerically analyzing forming conditions of press forming to obtain forming data of a press formed part, a springback analyzer for numerically analyzing said forming data to calculate a springback value, and a processor for processing at least one of a physical property value and physical property quantity data of part of the regions of said press formed part among forming data of said press formed part and making said springback analyzer calculate the springback value based on the results of said processing.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a Divisional of U.S. application Ser. No. 12 / 439,126 filed on Feb. 26, 2009, which was filed as the National Phase of PCT International Application No. PCT / JP2007 / 067358 filed on Aug. 30, 2007, which claims the benefit of priority to Japanese Application Nos. 2006-271097 filed Oct. 2, 2006, 2006-270693 filed Oct. 2, 2006, 2006-269253 filed Sep. 29, 2006, 2006-268855 filed Sep. 29, 2006, 2006-244351 filed Sep. 8, 2006 and 2006-236314 filed Aug. 31, 2006, all of which are hereby expressly incorporated by reference into the present application.BACKGROUND OF THE INVENTION[0002]The present invention relates to a method of identification of a cause of occurrence of springback occurring in a press formed product when press forming an automobile member etc. from steel sheet, steel bars, and other steel materials and also aluminum, magnesium, titanium, or other metals and a method of display of the degree of effect, a method of...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): G06F17/50
CPCG06F2217/16Y02T10/82G06F17/5018G06F2111/10G06F30/23B21D5/00
InventorYOSHIDA, TOHRUHIWATASHI, SHUNJIDAIMARU, SEIICHITANAKA, YASUHARUARIGA, TAKASHINIWA, TOSHIYUKIKURIYAMA, YUKIHISAOKAYAMA, SATORU
OwnerNIPPON STEEL CORP