Ballistic helmet and fabrication method
Methods and apparatus are provided for a seamless ballistic resistant helmet. In one exemplary embodiment the helmet comprises high performance fibers consolidated with a matrix material and arranged in a plurality of substantially seamless layers.
1. An apparatus for producing a pair of filament wound helmet shaped composite shells, comprising:
an enclosed mandrel comprising two helmet shaped ends symmetrically disposed about a longitudinal axis extending through an apex of each end;
a channel circumscribing the mandrel between the two helmet shaped ends;
an axle extending outward from each end of the mandrel along the longitudinal axis; and
a movable fiber dispensing head for winding high performance fibers onto the mandrel in a pre-defined manner.
2. The apparatus of claim 1 , wherein the channel is filled with a sacrificial material.
3. The apparatus of claim 1 , wherein the channel coincides with a brim edge of at least one of the helmet shaped ends.
4. The apparatus of claim 1 , wherein the axles are adapted to become an integral part of the helmet shaped composite shells.
5. A method of producing a pair of filament wound helmet shaped composite shells, comprising:
providing a mandrel with two helmet shaped ends symmetrically disposed about a longitudinal axis extending through an apex of each end;
winding a plurality of layers of high performance fibers in conjunction with a matrix material onto the mandrel forming a two-ended shell by dispensing the high performance fiber from a movable fiber dispensing head while the mandrel is rotated;
curing the two-ended shell; and
cutting the two-ended shell in half along a parting line between the two helmet shaped ends, and removing the two halves from each end of the mandrel.
6. The method of claim 5 , wherein the parting line coincides with a brim edge of at least one of the helmet shaped ends.
7. The method of claim 5 , wherein winding a plurality of layers of high performance fibers onto the mandrel forming a two-ended shell further comprises winding a plurality of layers with pre-defined fiber angles and coverage densities.
8. The method of claim 7 , wherein winding a plurality of layers of high performance fibers onto the mandrel forming a two-ended shell is automatically controlled at the direction of a controller executing a set of computer generated instructions.
9. The method of claim 5 , wherein the mandrel is supported for rotation without axles.