Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Study of Ligament Length Effect on Mode Mix of a Modified In-Plane Shear Test Specimen
Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. (Model Driven Development and Decision Support)ORCID iD: 0000-0002-1162-7023
Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Shanghai Second Polytechnic Univ., Faculty of Mech. & El. Eng., 201209, Shanghai, China. (Model Driven Development and Decision Support)
Kungliga Tekniska högskolan, SWE.
2016 (English)In: Materials Performance and Characterization, E-ISSN 2165-3992, ISSN 2165-3992, Vol. 5, no 3, 249-259 p.Article in journal (Refereed) Published
Abstract [en]

Shear fracture toughness is an important material behavior that needs to be determined and considered in many industrial fields. At the same time, shear testing is one of the complex material testing areas where available methods are few, often need special arrangements, and most of the methods do not strictly satisfy the definition of pure shear. In this study, a modified shear test specimen was proposed to measure the shear fracture toughness by uniaxial loading in a tensile testing machine. High density polyethylene (HDPE) was used as test material for the experiments. The specimen was created in order to suit the most common used tensile test machine. The specimen was then optimized by using finite element analysis (FEA) to find the geometry and the size of the pre-notch to avoid the mixed mode loading and minimize effects of normal stresses. For the specimen in discussion, an upper and lower limit of usable ligament length can be found. A method for determining the fracture toughness was discussed according to the essential work of fracture. Finally, an example of a special application of the proposed specimen was presented where the variation of shear strength of controlled delamination material (CDM) was measured.

Abstract [sv]

Shear brottseghet är ett viktigt material beteende som måste bestämmas och beaktas i många industriella områden. Samtidigt, testar skjuvning en av de komplexa materialtestområden där tillgängliga metoder är få, ofta behöver specialarrangemang, och de flesta av de metoder som inte strikt uppfyller definitionen av ren skjuvning. I denna studie var en modifierad skjuvning provstycket föreslås att mäta skjuv-brottsegheten genom enaxlig belastning i en dragprovningsmaskin. Högdensitetspolyeten (HDPE) användes som testmaterial för experimenten. Provet skapades för att passa den vanligaste använda dragtestmaskin. Provet därefter optimeras med användning av finit elementanalys (FEA) för att hitta den geometrin och storleken av för-hack för att undvika den blandat läge lastning och minimera effekterna av normala påkänningar. För provet i diskussionen kan hittas en övre och undre gräns för användbar ligament längd. En metod för att bestämma brottsegheten diskuterades i enlighet med den väsentliga brottarbetet. Slutligen ett exempel på en speciell tillämpning av den föreslagna provet presenteras där variationen av skjuvhållfastheten kontrollerad delamineringsmaterial (CDM) mättes.

Place, publisher, year, edition, pages
California, USA: ASTM International, 2016. Vol. 5, no 3, 249-259 p.
Keyword [en]
shear test specimen, polymers, fracture toughness, finite element simulation
National Category
Applied Mechanics
Identifiers
URN: urn:nbn:se:bth-12998DOI: 10.1520/MPC20150058ISI: 000406940600001OAI: oai:DiVA.org:bth-12998DiVA: diva2:958226
Available from: 2016-09-06 Created: 2016-09-06 Last updated: 2017-08-24Bibliographically approved
In thesis
1. Shear Fracture and Delamination in Packaging Materials: A study of Experimental Methods and Simulation Techniques
Open this publication in new window or tab >>Shear Fracture and Delamination in Packaging Materials: A study of Experimental Methods and Simulation Techniques
2016 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Packages are the means of preservation, distribution and convenience of use for food, medicine and other consumer products. Package opening is becoming complicated in many cases because of cutting cost in design and production of opening techniques. Introduction of new package opening technique, material or geometry for better opening experience, forces new design measurements which require a large number of prototype developments and physical testing. In order to achieve more rapid and accurate design, Finite Element Method (FEM) Simulations are widely used in packaging industries to compliment and reduce the number of physical testing.

The goal of this work is to develop the building blocks towards complete package opening simulation. The study focuses on testing and simulation of shear fracture and shear delamination of packaging materials. A modified shear test specimen was developed and optimized by finite element simulation. Test method was validated for High-density polyethylene (HDPE) and Polypropylene (PP). The developed method has been accepted by international standards organization ASTM. Based on linear elastic fracture mechanics, a geometry correction factor of shear fracture toughness for the proposed specimen was derived. The study concluded that, for ease of opening, HDPE is a more favorable material for screw caps than PP. When performing the experiment with the shear specimen to find essential work of fracture, the ligament length should be varied between twice of the thickness and half of the width of the specimen ligament.

Multi-layered thin laminate of Low-density polyethylene (LDPE) and aluminum (Al), also known as Al/LDPE laminate, is another key object addressed in this study. Continuum and fracture testing of individual layers provided the base information and input for numerical modeling. The propagation of an interfacial pre-crack in lamination in Al-LDPE laminate was simulated using several numerical techniques available in the commercial FEM solver ABAQUS, and it was concluded that using the combination of VCCT technique to model the interfacial delamination and coupled elasto-plastic damage constitutive for Al and LDPE substrates can describe interfacial delamination and failure due to necking. It was also concluded that the delamination mode in a pre-crack tip is influenced by the ratio of fracture energy release rate of mode I and II. To address the challenge in quantifying shear energy release rate of laminate with very thin substrate, a convenient test technique is proposed. Additionally, scanning electron microscopic study provided useful information on fractured and delaminated surfaces and provided evidence that strengthened the conclusions of this work.

The proposed test methods in this work will be crucial to measure the shear mechanical properties in bulk material and thin substrates. Laminates of Al and LDPE or similar material can be studied using the developed simulation technique which can be effectively used for decision support in early package development.

Place, publisher, year, edition, pages
Karlskrona: Blekinge Tekniska Högskola, 2016. 110 p.
Series
Blekinge Institute of Technology Licentiate Dissertation Series, ISSN 1650-2140 ; 5
Keyword
Package opening, Shear test specimen, Stress intensity factor, Finite Element simulation, Scanning electron microscopy, Polymers, Interlaminar shear delamination
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:bth-13340 (URN)978-91-7295-333-8 (ISBN)
Presentation
2016-12-09, J1650, Blekinge Tekniska Högskola, 37179 Karlskrona, 10:00 (English)
Opponent
Supervisors
Projects
model driven development and decision support project (MDS3)
Available from: 2016-11-09 Created: 2016-11-07 Last updated: 2017-05-02Bibliographically approved

Open Access in DiVA

Submitted version(990 kB)4 downloads
File information
File name FULLTEXT01.pdfFile size 990 kBChecksum SHA-512
05f8f1dd61b0f4c4ad109c2bdaa4ca5809927afcfd190ab4682ecdc4a66824ec0b18ea4c28ae2e578ae14de20b41d6827e82c7f8cc2df52cc1c19d15285b417f
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Islam, Md. ShafiqulKao-Walter, Sharon
By organisation
Department of Mechanical Engineering
In the same journal
Materials Performance and Characterization
Applied Mechanics

Search outside of DiVA

GoogleGoogle Scholar
Total: 4 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 145 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf