Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels

One of the latest challenges in sheet forming of crashworthy lightweight automotive parts is the cold stamping of curved hat channels. Neither cracking in convex bottom nor wrinkling in concave bottom can be avoided in conventional drawing. Tanaka and others have proposed in-plane shear forming tech...

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Main Authors: Kanayama Saaya, Yonebayashi Tohru, Tanaka Yasuharu, Hiwatashi Shunji
Format: Article
Language:English
Published: EDP Sciences 2025-01-01
Series:MATEC Web of Conferences
Subjects:
Online Access:https://www.matec-conferences.org/articles/matecconf/pdf/2025/02/matecconf_iddrg2025_01032.pdf
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author Kanayama Saaya
Yonebayashi Tohru
Tanaka Yasuharu
Hiwatashi Shunji
author_facet Kanayama Saaya
Yonebayashi Tohru
Tanaka Yasuharu
Hiwatashi Shunji
author_sort Kanayama Saaya
collection DOAJ
description One of the latest challenges in sheet forming of crashworthy lightweight automotive parts is the cold stamping of curved hat channels. Neither cracking in convex bottom nor wrinkling in concave bottom can be avoided in conventional drawing. Tanaka and others have proposed in-plane shear forming technology, in which shear strains are given to vertical walls by pad draw-bending for the case of curved channels. This requires a sufficient pad force to clamp the bottom face area; however, the minimum pad force for successful forming can be known only by trial and error. In this study, we focused on cracking in convex bottom and examined a method to estimate the required pad force. Finite element simulations and forming experiments for a 980-MPa-grade steel led to a theoretical model in which three types of force were applied to the flat bottom during forming: a force given by in-plane shear of walls, a frictional force given by the pad force for clamping, and a resistance against the flow to the convex bottom. The required pad force could then be obtained as a solution of the equilibrium of these forces. Furthermore, the validity of the proposed method was confirmed.
format Article
id doaj-art-06fb1985a4d840a5ba3e70f91ef2582f
institution OA Journals
issn 2261-236X
language English
publishDate 2025-01-01
publisher EDP Sciences
record_format Article
series MATEC Web of Conferences
spelling doaj-art-06fb1985a4d840a5ba3e70f91ef2582f2025-08-20T01:53:37ZengEDP SciencesMATEC Web of Conferences2261-236X2025-01-014080103210.1051/matecconf/202540801032matecconf_iddrg2025_01032Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength SteelsKanayama Saaya0Yonebayashi Tohru1Tanaka Yasuharu2Hiwatashi Shunji3Nippon Steel Corporation, Research & DevelopmentNippon Steel Corporation, Research & DevelopmentNippon Steel Corporation, Nagoya WorksNippon Steel Corporation, Research & DevelopmentOne of the latest challenges in sheet forming of crashworthy lightweight automotive parts is the cold stamping of curved hat channels. Neither cracking in convex bottom nor wrinkling in concave bottom can be avoided in conventional drawing. Tanaka and others have proposed in-plane shear forming technology, in which shear strains are given to vertical walls by pad draw-bending for the case of curved channels. This requires a sufficient pad force to clamp the bottom face area; however, the minimum pad force for successful forming can be known only by trial and error. In this study, we focused on cracking in convex bottom and examined a method to estimate the required pad force. Finite element simulations and forming experiments for a 980-MPa-grade steel led to a theoretical model in which three types of force were applied to the flat bottom during forming: a force given by in-plane shear of walls, a frictional force given by the pad force for clamping, and a resistance against the flow to the convex bottom. The required pad force could then be obtained as a solution of the equilibrium of these forces. Furthermore, the validity of the proposed method was confirmed.https://www.matec-conferences.org/articles/matecconf/pdf/2025/02/matecconf_iddrg2025_01032.pdfproduction manufactureforming processultra-high-strength steelsheet forming
spellingShingle Kanayama Saaya
Yonebayashi Tohru
Tanaka Yasuharu
Hiwatashi Shunji
Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels
MATEC Web of Conferences
production manufacture
forming process
ultra-high-strength steel
sheet forming
title Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels
title_full Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels
title_fullStr Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels
title_full_unstemmed Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels
title_short Pad Force Required in Shear-deformation Sheet Forming of Curved Hat Channels for Ultra-High-Strength Steels
title_sort pad force required in shear deformation sheet forming of curved hat channels for ultra high strength steels
topic production manufacture
forming process
ultra-high-strength steel
sheet forming
url https://www.matec-conferences.org/articles/matecconf/pdf/2025/02/matecconf_iddrg2025_01032.pdf
work_keys_str_mv AT kanayamasaaya padforcerequiredinsheardeformationsheetformingofcurvedhatchannelsforultrahighstrengthsteels
AT yonebayashitohru padforcerequiredinsheardeformationsheetformingofcurvedhatchannelsforultrahighstrengthsteels
AT tanakayasuharu padforcerequiredinsheardeformationsheetformingofcurvedhatchannelsforultrahighstrengthsteels
AT hiwatashishunji padforcerequiredinsheardeformationsheetformingofcurvedhatchannelsforultrahighstrengthsteels