Advanced

On buckling and fracture of thin elastic-plastic foils : Part of special issue: 1st Virtual European Conference on Fracture - VECF1

Ståhle, Per LU ; Shahmardani, Mahdieh and Kao-Walter, Sharon (2020) 1st Virtual European Conference on Fracture, VECF 2020 In Procedia Structural Integrity 28. p.2065-2071
Abstract

The interaction of simultaneous fracture and buckling constitutes problems at manufacturing and handling of thin foils. Buckling occurs as an additional event that complicates the prediction of the critical load that may lead to fracture. For most sufficiently thin foils the plastic slip occurs through the foil thickness which leads to reduction of the cross section width until the foil fails. The process leads to a necking type of deformation which confines itself to a narrow region that extends ahead of the crack tip. The width of the region is close to the foil thickness. At failure the width of the necking region is twice the foil thickness. In the present investigation the crack is assumed to be small compared to the foil geometry... (More)

The interaction of simultaneous fracture and buckling constitutes problems at manufacturing and handling of thin foils. Buckling occurs as an additional event that complicates the prediction of the critical load that may lead to fracture. For most sufficiently thin foils the plastic slip occurs through the foil thickness which leads to reduction of the cross section width until the foil fails. The process leads to a necking type of deformation which confines itself to a narrow region that extends ahead of the crack tip. The width of the region is close to the foil thickness. At failure the width of the necking region is twice the foil thickness. In the present investigation the crack is assumed to be small compared to the foil geometry and the foil is assumed to be small compared with the crack length. Because of the latter the necking type of plastic region is modelled as a cohesive zone. Since the fracture toughness is not involved in the failure the only two relevant length parameters are crack length and foil thickness. The material model is defined by the elastic modulus, Poisson's ratio and yield stress. The remote load at buckling and at failure is determined and given on dimensionless form, which leaves Poisson's ratio and the ratio of buckling stress versus failure stress as the only free parameters. Two scales of yielding, the load at the ASTM-limit for linear fracture mechanics and twice that load, including the purely elastic result are investigated. Poisson's ratio is varied in the interval from -0.9 to 0.5 for the elastic case and from -0.6 to 0.5 for the plastic cases. The lower theoretical limit -1 for Poisson's ratio was not obtained because of numerical difficulties. The results rules out the possibility of failure before buckling for any reasonable construction material.

(Less)
Please use this url to cite or link to this publication:
author
; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Buckling, Cohesive zone, Elastic-Plastic, Fracture, Metal, Necking, Thin foil
host publication
Procedia Structural Integrity
series title
Procedia Structural Integrity
volume
28
pages
7 pages
conference name
1st Virtual European Conference on Fracture, VECF 2020
conference location
Virtual, Online
conference dates
2020-06-29 - 2020-07-01
external identifiers
  • scopus:85099848704
ISSN
2452-3216
DOI
10.1016/j.prostr.2020.11.030
language
English
LU publication?
yes
additional info
Funding Information: Support from Blekinge Institute of Technology and Tetra Pak is gratefully acknowledged. Publisher Copyright: © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
id
0b09750b-7c8d-4216-b38c-1e06a530336d
date added to LUP
2021-03-04 09:20:32
date last changed
2021-03-05 11:13:53
@inproceedings{0b09750b-7c8d-4216-b38c-1e06a530336d,
  abstract     = {<p>The interaction of simultaneous fracture and buckling constitutes problems at manufacturing and handling of thin foils. Buckling occurs as an additional event that complicates the prediction of the critical load that may lead to fracture. For most sufficiently thin foils the plastic slip occurs through the foil thickness which leads to reduction of the cross section width until the foil fails. The process leads to a necking type of deformation which confines itself to a narrow region that extends ahead of the crack tip. The width of the region is close to the foil thickness. At failure the width of the necking region is twice the foil thickness. In the present investigation the crack is assumed to be small compared to the foil geometry and the foil is assumed to be small compared with the crack length. Because of the latter the necking type of plastic region is modelled as a cohesive zone. Since the fracture toughness is not involved in the failure the only two relevant length parameters are crack length and foil thickness. The material model is defined by the elastic modulus, Poisson's ratio and yield stress. The remote load at buckling and at failure is determined and given on dimensionless form, which leaves Poisson's ratio and the ratio of buckling stress versus failure stress as the only free parameters. Two scales of yielding, the load at the ASTM-limit for linear fracture mechanics and twice that load, including the purely elastic result are investigated. Poisson's ratio is varied in the interval from -0.9 to 0.5 for the elastic case and from -0.6 to 0.5 for the plastic cases. The lower theoretical limit -1 for Poisson's ratio was not obtained because of numerical difficulties. The results rules out the possibility of failure before buckling for any reasonable construction material.</p>},
  author       = {Ståhle, Per and Shahmardani, Mahdieh and Kao-Walter, Sharon},
  booktitle    = {Procedia Structural Integrity},
  issn         = {2452-3216},
  language     = {eng},
  pages        = {2065--2071},
  series       = {Procedia Structural Integrity},
  title        = {On buckling and fracture of thin elastic-plastic foils : Part of special issue: 1st Virtual European Conference on Fracture - VECF1},
  url          = {http://dx.doi.org/10.1016/j.prostr.2020.11.030},
  doi          = {10.1016/j.prostr.2020.11.030},
  volume       = {28},
  year         = {2020},
}