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A concept for defining the mixed-mode behaviour of tough epoxy film adhesives by single specimen design

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Pages (from-to)1982-1999
Number of pages18
JournalJournal of Adhesion Science and Technology
Volume34
Issue number18
DOIs
Publication statusPublished - 2020
Publication typeA1 Journal article-refereed

Abstract

Fracture modes I and II interact in mixed-mode loading conditions, and the interaction is typically taken into account using a mixed-mode fracture criterion. In this work, a concept for defining the criterion is developed through an experimental-numerical simulation analysis. The mixed-mode behaviour for the criterion is tested and analysed with a single specimen design. The design of the specimen simplifies the measurement when complex test arrangements and preparations for various specimen geometries are excluded in practice. Here, the mixed-mode fracture behaviour of the specimen is analysed in detail using digital image correlation (DIC). The DIC data are used in collaboration with a finite element–based crack onset analysis, including the virtual crack closure technique, in order to consider the typical simplifications and their effects on the mixed-mode criterion. As a benchmark case, the fracture criterion is determined for an epoxy film adhesive FM 300-2 using the developed approach. The developed approach was shown to be feasible and effective for defining the mixed-mode fracture criterion. The determined Power law criterion’s exponents were below unity, which points out that the common (presumed) exponent values in the current literature are actually unconservative.

Keywords

  • adhesive, mixed-mode testing, epoxy, virtual crack closure technique, digital image correlation

Publication forum classification

Field of science, Statistics Finland