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Effect of delamination on the response of advanced composite laminates

Thesis/Dissertation ·
OSTI ID:6334619

Advanced composites are very susceptible to internal delamination failures. This report represents an attempt to understand the effects of delaminations of the stiffness-dominated response of a simple structural element, the beam column. Graphite-epoxy beam-column samples with various-length delaminations were tested in static bending, free vibrations, and buckling response. The finite-element method was used to corroborate the experimental results. Beam-theory models capable of analyzing delaminated cross-ply laminates composed of symmetric sublaminates were developed to allow efficient analysis of delamination effects. Both three- and four-point bending tests were used to determine the effect of delaminations on laminate bending stiffness. The delaminations did not cause any degradation of the four-point bending stiffness. However, the three-point bending stiffness test showed that the delamination did degrade the stiffness by as much as 34%. The effect of delaminations of the free-vibration response was determined using experimental modal analysis.

Research Organization:
California Univ., Irvine (USA)
OSTI ID:
6334619
Country of Publication:
United States
Language:
English