Paper number 901

IMPACT OF PLY DROPS

K. C. Kairouz and J. Ball

British Aerospace Airbus, New Filton House, Filton, Bristol BS99 7AR, England, U.K.

Summary This paper covers impact testing of ply drop features, using non-crimp fabric composite material. It has been found that, whilst the energy to initiate damage may vary, the threshold force for damage initiation is constant. An impact damage growth parameter has been proposed to assess the extent of impact damage growth. It has been shown that the impact performance of ply drop specimens is more critical than the equivalent flat laminate. The emphasis of this study is to establish a basic understanding of the underlying failure mechanisms associated with the impact response of ply drop features and the implications for structural design. Experimental results were formulated into simple rules for design purposes. Some limited, quasi-static, finite element analysis was undertaken, and the results were compared to experimental observations.
Keywords impact, ply drops, threshold force, threshold energy, test rig, finite element analysis.

Theme : Mechanical and Physical Properties ; Dynamic, Impact and crashworthiness

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