Influence of molding pressure on blunt trauma effect and ballistic properties of unidirectional and bidirectional composites based on ultra high molecular weight polyethylene fibers

The influence of molding pressure on blunt traume effect and ballistic strength of unidirectional and bidirectional composites based on UHMWPE (Ultra Hight Molecular Weight Polyethylene) fibers is investigated. Two types of unidirectional and one type of bidirectional composites molded at 20, 60 and 100 bar were tested on their ballistic strength and their blunt traume depth and area were measured. It was found out that by increasing the molding pressure the blunt trauma effect was decreased by unidirectional composites and vice versa. The measurement of ballistic strengtht has shown that the bidirectional composites show about 25% lower ballistic strength with much more pronounced delamaniatin tendency by multiple strikes, than the unidirectional composites. Bidirectional composites did not show any tendentious change in ballistic strength with the molding pressure change