3D numerical and experimental investigation of hypervelocity impacts on dual bumper plate Whipple shields for spacecraft protection

Dual Bumper Whipple shields have been employed for spacecraft protection for many decades, with extensive experimental and numerical studies dedicated to characterizing their impact resistance. Over the years, advancements have introduced novel design modifications, including fluid-filled containments, foam-filled cores, and shear-thickening fluids in the inter-bumper spaces, enhancing their protective capabilities. While hypervelocity impact (HVI) experiments provide valuable insights, they remain expensive, time-intensive, and demand sophisticated equipment and expertise. To address these challenges, numerical simulations have been widely utilized; however, most studies have predominantly relied on 2D simulations, often assuming axi-symmetric plate behavior. In this work, a fully 3D numerical simulation model was developed using ANSYS® Explicit Dynamics to address these limitations, providing a more detailed understanding of debris behavior and shield performance under hypervelocity impact conditions. The model was further refined to closely replicate the experimental response of bumper plates subjected to HVI. HVI experiments were conducted using 2 mm diameter stainless steel spherical projectiles impacting dual bumper plate Whipple shields, consisting of 1 mm thick AA6061-T6 plates with a 10 mm inter-bumper spacing. Both experimental and numerical approaches were employed to analyze perforation characteristics, ejecta formation, debris growth and propagation, and overall damage patterns. Additionally, the numerical model offered deeper insights into energy variation, stress distribution, plastic strain, and deformation. The axial velocity measurements of the debris cloud demonstrated good agreement between experimental and numerical results, further validating the accuracy of the 3D simulation model.