Performance analysis of fluid-core Whipple shields under hypervelocity impact at different projectile speeds

Whipple shields as sacrificial bumpers, safeguard the satellites against extremely fast, different-sized projectiles traveling through space in the low earth orbit. Typical Whipple shields comprise a front and rear plate, separated by a gap or space. Recent advancements have explored the use of foam, cellular cores, and alternative materials such as ceramics instead of aluminium for the plates. In the current work, the effect of including fluid cores (air/water) sandwiched between the front and rear plates, on the response to hypervelocity impact was explored through a numerical approach. The numerical simulation consisted of hypervelocity impact by a 2 mm diameter, stainless steel projectile, launched at speeds of 3–9 km/s with a normal impact trajectory towards the Whipple shield. The front and rear bumpers, made of AA6061-T6, were each 1 mm thick. A space of 10 mm was taken between the plates (occupied by fluid). The key metrics analyzed were the perforation characteristics, stages of the debris cloud generation and propagation, energy variations (internal, kinetic and plastic work), temperature variations, and the fragmentation summary. From the computational analysis, employing water-core in Whipple shields could prevent the rear bumper perforation till 6 km/s, lower the peak temperatures at the front bumper perforation zones and debris tip, and generate fewer, larger fragments.