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Damage and failure analysis of continuous fiber-reinforced polymer composites

Chen, Fuh-Sheng

Abstract Details

1992, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science.
In the chapter one, the damage that accompanies flexural deformation of a unidirectional glass fiber reinforced polyphenylene sulfide composite was examined by acoustic emission (AE) and scanning electron microscopy (SEM). The flexural stress-strain curve was nominally linear to about 1.0% strain, but the onset of damage detectable by AE occurred at 0.3% strain. Two peaks in the AE amplitude distribution were observed at 35dB and 60dB. Low amplitude events were detected along the entire length of the specimen. SEM observations suggested that these events arose from matrix cracking and fiber debonding. High amplitude events occurred primarily in the region of highest flexural stress between the inner loading points, they were attributed to fracture of glass fibers on the tension side and surface damage on the compressive side. In the chapters two and three, the effects of the matrix modulus on the compressive failure mechanisms in flexure of unidirectional glass fiber reinforced thermoplastic Hytrel composites has been studied. An increase in the matrix Young's modulus leads to a change in the failure mode from cooperative fiber microbuckling to delamination splitting microbuckling. Cooperative fiber microbuckling is a catastrophic phenomenon without significant damage occurring in the composite system prior to the abrupt failure. Fibers are buckled both in the plane and normal to the plane of the compression surface. Delamination splitting microbuckling is associated with matrix splitting and consists of gradual accumulation of localized surface delaminations followed by buckling of fiber bundles. The transition in the mechanisms of flexural failure is semi-quantitatively explained by considering the criterion for each of the failure modes. The failure strength for cooperative fiber microbuckling is controlled by the shear modulus of the composite which is linear related to the Young's modulus of the matrix, while the failure strength for delamination splitting microbuckling is controlled by the composite shear strength which is not strongly affected on the Young's modulus of the matrix. Because the critical failure stresses have different dependencies on the matrix modulus, a transition from cooperative fiber microbuckling to delamination splitting microbuckling occurs as the matrix modulus increases.
Anne Hiltner (Advisor)
178 p.

Recommended Citations

Citations

  • Chen, F.-S. (1992). Damage and failure analysis of continuous fiber-reinforced polymer composites [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1056554068

    APA Style (7th edition)

  • Chen, Fuh-Sheng. Damage and failure analysis of continuous fiber-reinforced polymer composites. 1992. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1056554068.

    MLA Style (8th edition)

  • Chen, Fuh-Sheng. "Damage and failure analysis of continuous fiber-reinforced polymer composites." Doctoral dissertation, Case Western Reserve University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=case1056554068

    Chicago Manual of Style (17th edition)