Ballistic performance and energy transfer of ultrahigh molecular weight polyethylene laminate.

• Back bulge bottom shape changes from circle to diamond, and then to square shape. • The front face shows square-shaped bullet holes and a cross-shaped failure. • Strain distribution shows an L-shape and the max value is around 0.18. • 80.64% of bullet's kinetic energy converts to laminate's kinetic & internal energy. Soldier protection is crucial in contemporary localized conflicts, However, the impact response mechanism of UHMWPE laminate as the insert plate of ballistic helmet and bulletproof vest is still unclear. This study utilized 3D-DIC technology to analyze the impact response of UHMWPE laminates subjected to a 9 mm lead-core pistol bullet at a velocity of 334.93 m/s. The damage mode and response characteristics of the back surface were revealed; an effective numerical calculation method was established and could reveal the energy conversion process. The bullet penetrated the front face with 1.01 mm, resulting in a cross-shaped failure feature due to fiber bundle compression and aggregation. The numerical model confirmed its accuracy by comparing the height, width, and inplane strain distribution within the inplane of the bulge with experimental results. It further investigated the interaction between the bullet and the laminate, and energy transformation. The bullet's kinetic energy decreased by 80.64 %, in which the laminate absorbs 30.84 % of the bullet's energy as internal energy and 35.06 % as kinetic energy, meanwhile the bullet's internal energy increases by 11.77 %. The results show the damage mode and energy transformation of laminate, which provides theoretical support for revealing the impact response mechanism and improving the protective energy absorption efficiency. [ABSTRACT FROM AUTHOR]