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Determination of initiation value of mode I interlaminar fracture toughness of unidirectional polymer composites
Author(s) -
He Tianbai,
Zhou Jiang,
Liu Weilian
Publication year - 1993
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.750140313
Subject(s) - materials science , composite material , fracture toughness , fiber pull out , delamination (geology) , composite laminates , bridging (networking) , composite number , thermosetting polymer , fracture (geology) , fracture mechanics , toughness , paleontology , computer network , biology , computer science , subduction , tectonics
The use of interlaminar fracture tests to measure the delamination resistance of unidirectional composite laminates is now widespread. However, because of the frequent occurrence of fiber bridging and multiple cracking during the tests, it leads to artificially high values of delamination resistance, which will not represent the behavior of the laminates. Initiation fracture from the crack starter, on the other hand, does not involve bridging, and should be more representative of the delamination resistance of the composite laminates. Since there is some uncertainty involved in determining the initiation value of delamination resistance in mode I tests in the literature, a power law of the form G IC = A · Δ a b (where G IC is mode I interlaminar fracture toughness and Δ a is delamination growth) is presented in this paper to determine initiation value of mode I interlaminar fracture toughness. It is found that initiation values of the mode I interlaminar fracture toughness. G IC ini , can be defined as the G IC value at which 1 mm of delamination from the crack starter has occurred. Examples of initiation values determined by this method are given for both carbon fiber reinforced thermoplastic and thermosetting polymers.