AN APPARATUS FOR FOLDING YARNS AND WOVEN FABRICS OF BALLISTIC FIBERS

摘要

Folding of ballistic fibers comprising soft body armor may be a factor in the performancerndeterioration that has been observed in used soft body armor. To quantify the impact of thisrnmechanism, an apparatus was designed and built to simulate the folding that may occur to thernballistic fibers while the vest is in use. The device systematically folds woven fabric and yarns ofrnballistic fibers to assess the impact of folding on ballistic fiber properties. Initial test resultsrnindicate that the device does repeatedly fold a piece of woven fabric at the same location. Afterrncycling a piece of woven poly(benzoxazole) (PBO) fabric for 5,500 cycles, a 14 % reduction inrnthe ultimate tensile strength and strain to failure of the PBO fibers was observed. Research isrncontinuing to optimize the testing procedure. It is anticipated that this device will be a usefulrntool in understanding how ballistic fibers degrade.