Shape- Optimized Bubbled- Armour Forms for High Resistance to Ballistic Penetration

In this study, bubbled- armour forms are assessed for ballistic penetration resistance. A key component is optimization of the bubble shape to maximize its fundamental modal frequency. A 'large- plastic- regime' automotive steel alloy is adopted for the bubble and the penetration process simulated by LS- DYNA for a 'rigid' projectile. Three forms: - a flat-, spherical and the shape- optimized one, of identical planform dimensions and mass, are studied for their penetration resistance characteristics under a common impact speed. The optimum form is found to be the most superior, causing a momentum loss of as much as 140%, implying a total reversal of the projectile, post- impact. This is more than the 111% for the spherical form and far above the 30% for the flat form. Modal response also correlates well with impact- induced bubble- response acceleration in wavelet decomposition. We conclude that with the fundamental modal frequency maximized, shape- optimized bubbled- armour forms can have much higher penetration resistance than a traditional plate armour's.