Applications of polyurea coatings in blast and ballistic damage reduction

Metal-polyurea composites have gained significant interest as a potential composite in resisting blast and ballistic impact loads. Although the loading mechanisms are different for these two types of loading, they both fall under the category of high-strain-inducing loads. Resisting such loads require high energy absorption capabilities, which is the main advantage that has promoted the use of elastomers such as polyurea in these applications. This chapter presents the findings of experimental and numerical investigations involving metal-polyurea composites under a blast load equivalent to 1 kg of trinitrotoluene at a standoff distance of 150 mm and a ballistic load of a projectile fired at an approximate velocity of 930 m/s. The blast tests revealed that the steel plates with polyurea coating at the back face yielded lower residual deflection as well as minimum damage to the polyurea coating than the plates with coatings at the front face. It was also identified that an optimum coating thickness can be found for a given system, where beyond this threshold, the increase in aerial density due to the coating overrides the gains achieved by the enhanced energy absorption capability of the polyurea coating. In the ballistic trials, it was observed that when considering the reduction in the residual velocity of the projectile per aerial density of the plate system, it is advantageous to use polyurea coatings in between aluminum plates, as opposed to increasing the thickness of aluminum plates. Overall, based on the positive findings of these studies, complemented by the advances in polyurea-metal coating techniques and the lower density of polyurea, there is scope for further studies to optimize the performances of metal-polyurea composites, to be used in the blast and ballistic-related applications.