Evaluation of mode II fracture toughness in unidirectional GFRP using four-point shear loading test and its fracture mechanism

Hiroyuki Kawada, Yutaka Ochi, Hiroshi Shimanuki, Ikuhiko Hayashi

    Research output: Contribution to journalArticle

    Abstract

    Mode II fracture toughness tests of unidirectional GFRP were conducted using a four-point shear loading test method. This test method was a modified Iosipescu test method which was identified to be the most reliable one for obtaining a shear stress-strain relation in composite materials. In this study, a leverage ratio of the loading and a pre-crack length ratio of the specimen were examined to perform the fracture toughness tests. Fracture behavior of the unidirectional GFRP under shear loading was investigated through a fractographic observation. The results obtained are summarized as follows: (1) The four-point shear loading test method can be assessed at a simplified in-plane mode II fracture toughness test. To prevent premature failures without reinforcement attached to the specimen, it is necessary for the pre-crack length ratio, a/W to be larger than 0.3 under the definite leverage ratio. (2) The mode II fracture toughness evaluated in terms of stress intensity factors at the maximum load points was found to be dependent on the pre-crack length ratio. (3) The Hackle patterns were confirmed at a stable crack propagation region which are typical fracture traces on the matrix under the shear loading. The formation mechanism of the Hackle at different parts was investigated in detail, and then the physical meaning of the fracture toughness obtained in this experiment was discussed.

    Original languageEnglish
    Pages (from-to)875-881
    Number of pages7
    JournalZairyo/Journal of the Society of Materials Science, Japan
    Volume40
    Issue number454
    Publication statusPublished - 1991 Jul

    Fingerprint

    fracture strength
    Fracture toughness
    shear
    evaluation
    Cracks
    cracks
    Stress intensity factors
    Shear stress
    Crack propagation
    Loads (forces)
    stress intensity factors
    Reinforcement
    crack propagation
    reinforcement
    shear stress
    Composite materials
    composite materials
    Experiments
    matrices

    ASJC Scopus subject areas

    • Chemical Engineering (miscellaneous)
    • Metals and Alloys
    • Polymers and Plastics

    Cite this

    Evaluation of mode II fracture toughness in unidirectional GFRP using four-point shear loading test and its fracture mechanism. / Kawada, Hiroyuki; Ochi, Yutaka; Shimanuki, Hiroshi; Hayashi, Ikuhiko.

    In: Zairyo/Journal of the Society of Materials Science, Japan, Vol. 40, No. 454, 07.1991, p. 875-881.

    Research output: Contribution to journalArticle

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