Digital Imaging and Fractographical Analyzes of Perforation-induced Delamination of Laminated Graphite-Epoxy Composite

Abstract

A digital imaging technique for characterizing dynamic delamination in laminated composites is presented in this article. Perforation-induced delamination surfaces are generated using a conical and protruding hemispherical penetrators applied in the thickness direction using penetrating split Hopkinson pressure bar (P-SHPB). The results reveal that the extent of delamination depends strongly on the shape and geometry of the penetrator. Delamination is the dominant mode of failure for the conical hemispherical penetrator below the perforation limit energy but competes with matrix cracking at energy above the perforation limit. With the protruding penetrator, delamination mode continues to dominate at all energies. Hackles formation is not a characteristic of perforation-induced delamination.

High Strain Rate Compressive Tests on Wood

“…Neglecting the specimen deflection in this case, equilibrium at the interfaces between the incident (input) and transmitted (output) bars requires that ∑ F = 0 for each interface. Therefore, the absorbed energy can be calculated by the strain measurements on the input and output bars and the geometry of the bars and specimen used in the tests [14, 15]. The continuity condition of velocity and force equilibrium conditions at the specimen–bar interface gives the specimen particle velocity ( v s ) as, …”

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