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Abstract

This work discusses the behavior of 8-ply, quasi-isotropic, graphite epoxy laminates subjected to low velocity transverse impact loading. Large deflection theory of plates was used to predict the load-deflection characteristics during the impact event. The im pact model considered that the indentation, flexural and shear stiffnesses could be represented by 3-equivalent springs in series.

The analysis of static and dynamic impact loading test-data concluded that the mem brane parameter, β, used in flexural stiffness relation was proportional to the square of the coefficient of restitution, e, of the impactor. Use of β = 0.443 e² was made in load- deflection relations to consider the drop in plate stiffness due to delamination.

The results of impact tests up to impact velocity 5.3 m/sec. were found in close agreement of the predictions.

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References

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Elber, W. , "Deformation and Failure Mechanics in Low Velocity Impacts on Thin Composite Plates," Proc. of the Army Symposium on Solid Mechanics, 1982, pp. 288-317.

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Lal, K.M. , "Coefficient of Restitution for Low Velocity Transverse Impact of Thin GraphiteEpoxy Laminates," NASA Grant No. NAG-1-196, Progress Report April, 1983.

Low Velocity Transverse Impact Behavior of 8-ply,Graphite-Epoxy Laminates

Abstract

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