STP1230: Influence of Realistic Ply-Drop Geometries on Interlaminar Stresses in Tapered Laminates

    Vizzini, AJ
    Associate professor, University of Maryland, College Park, MD

    Pages: 19    Published: Jan 1995


    Abstract

    A finite element model of a tapered specimen was developed that incorporates naturally occurring realistic geometries such as ill-formed resin pockets, unsymmetric and offset ply-drop locations, varying ply thickness, and voids. Parametric studies were performed to determine the effects of these geometries, which occur naturally in a manufactured specimen. Illformed resin pockets increase the effective taper angle at the ply drop and cause a corresponding increase in the interlaminar stresses. In addition, the onset of damage location is dependent on the geometry of the ill-formed pocket. The effect of ply drops occurring unsymmetrically about the midplane is significant for offset values that occur as a result of the manufacturing process. Again the location for damage onset is dependent on the amount of the offset of the resin pocket. Voids or fracture within the resin pockets significantly increase the interlaminar stress at the ply drop and thus decrease the damage onset load within the tapered element.

    Keywords:

    taper, ply drop, interlaminar stresses, delamination, glass/epoxy


    Paper ID: STP14030S

    Committee/Subcommittee: D30.06

    DOI: 10.1520/STP14030S


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