Numerical investigation of ballistic performance of sandwich panels with quasi-corrugated cores under high-velocity impact

Sandwich panels are widely used in various industries such as aerospace, marine, and automotive due to their high strength-to-weight ratio and excellent energy absorption capability. In this study, the ballistic resistance of sandwich panels with aluminum 1050 and polyurea face sheets and semi cylindrical and hemi-spherical quasi-corrugated cores are numerically investigated. The effects of curvature, core wave geometry, number and arrangement of core layers, presence of the polyurea layer, and projectile impact location on the core are examined. The panels are subjected to high-velocity impacts (ranging from 50 to 408 m/s) using a flat-nosed cylindrical projectile with a diameter of 7.62 mm and a length of 25.4 mm. The main objective of this study is to enhance the specific ballistic resistance (strength-to-weight ratio) of sandwich panels. The main results indicate that by changing the core geometry from flat to curved, the ballistic limit velocity and the specific ballistic strength increased by 7.5% and 6%, respectively. In single-layer cores, changing the core wave geometry from hemi-spherical to semi-cylindrical resulted in a 12.3% increase in ballistic limit velocity and a 26.1% increase in specific ballistic strength. In double-layer cores, rearranging the layers with different wave geometries (from semi cylindrical–hemi spherical to hemi spherical–semi cylindrical) led to increases of 4.2% and 22.1% in ballistic limit velocity and specific ballistic strength, respectively. The use of a polyurea face sheet in the sandwich panel increased the ballistic limit velocity and specific ballistic strength by 37.7% and 45.7%, respectively.