STP876

    Moisture and Temperature Effects on the Mixed-Mode Delamination Fracture of Unidirectional Graphite/Epoxy

    Published: Jan 1985


      Format Pages Price  
    PDF Version (428K) 22 $25   ADD TO CART
    Complete Source PDF (8.7M) 22 $70   ADD TO CART


    Abstract

    The critical strain energy release rates for interlaminar fracture of unidirectional graphite/epoxy, both from a sharp notch and as a function of crack extension, were determined experimentally for combined tensile/shear loadings. Based on well-founded compliance techniques, a substantial database was generated over the temperature range −50°C to 100°C for both dry and moisture-saturated states. The fracture energy of the unreinforced epoxy matrix material was also measured. Initiation energies for delamination increased as the proportion of shear loading increased and as the temperature was lowered but were insensitive to moisture content. The fracture resistance to crack extension increased under tensile dominated loadings with both temperature and moisture content but remained constant for high shear loadings. The applicability of various mixed-mode fracture criteria to both the present data and to available literature data is examined. The Wu fracture model was modified to take into account plane strain conditions appropriate to delamination. Crack growth resistance behavior is discussed in terms of the micromechanisms occurring close to the crack tip.

    Keywords:

    delamination, interlaminar fracture, strain energy release rate, fracture energy, mixed-mode fracture criterion, graphite/epoxy, moisture, temperature, composite material


    Author Information:

    Russell, AJ
    Defence Research Establishment Pacific, Victoria, British Columbia

    Street, KN
    Defence Research Establishment Pacific, Victoria, British Columbia


    Paper ID: STP36314S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP36314S


    CrossRef ASTM International is a member of CrossRef.