Low Velocity Transverse Normal Impact of Graphite Epoxy Composite Laminates.
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA AIR VEHICLE TECHNOLOGY DEPT
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A combined theoretical-experimental approach has been initiated to determine the response of generic composite structural elements to low speed, transverse normal, hard object impact dropped tool, runway stones, etc.. Static and low velocity central impact drop tests were conducted employing simply supported solid laminate specimens. The graphite epoxy laminate specimens were 3 in. wide x 6 in. span x 0.084 in. thick plus or minus 45O sub 2plus or minus 45 sub S. A variable mass steel impactor with a two inch tip diameter was used in these tests. Results of this investigation showed that as the velocity of impact is increased it requires less impactor kinetic energy to produce damage. The initial mathematical model consisted of a uniform Bernoulli-Euler beam and a rigid impactor concentrated mass. Displacement and velocity distributions at the instant of contact were assumed as initial conditions and the solution was expanded in the set of orthogonal eigenfunctions of the free vibration problem using Galerkins method. Good correlation of experimental with analytical results have been obtained over the velocity range from 0 to 20 feet per second.
- Laminates and Composite Materials