The effect of in-plane shear properties on the ballistic performance of polyethylene composites

Using developed experimental and analytical methods for in-plane shear characterization of quasi-statically loaded polyethylene (PE) laminates, this work evaluates the effect of the in-plane shear behavior has on ballistic performance (limit velocity and back face deflection). As in-plane shear is a matrix-dominated phenomena and processing pressure is known to noticeably influence the shear properties of polyethylene composites, the matrix materials and processing conditions are varied in order to probe an array of configurations. The in-plane shear properties are assessed through quasi-static tensile testing of laminates with [+/- 45 degrees] orientation and the ballistic performance is evaluated using a laboratory gas gun and high speed DIC. It is found that the in-plane shear strain for the more compliant HB 212 material is twice that of the HB 210 material during a ballistic event, which corresponds to the 5% increase in limit velocity of HB 212 over HB 210. The source of the shear deformation in PE materials is fiber rotation as evidenced by the quasi static tests.