Flexible Honeycomb Composite Vehicle Armor 2009-01-0601

Composite sandwich structures have been widely used in the aerospace, defense and automotive industries because of their high specific bending stiffness and strength against distributed loads. They have increasingly been expected to be damage-tolerant and energy-absorbing. Under concentrated loads, a multitude of damage mechanisms induced affects their subsequent residual performance, especially in in-plane compression.

American Engineering Group (AEG) has developed a Reinforced Honeycomb (RDH) to develop an energy absorbing flexible vehicle armor. This unique reinforced honeycomb structure will help in reducing the severity of impact effects of from rounds at muzzle velocity. AEG will design this lightweight flexible composite energy absorbing core with superior blast resistant honeycomb structure using micro-structural “waiting elements” inside the honeycomb cells filled with shear thickening silicone gel. These inner micro-structures are circular or hexagonal elements and will be shorter than main structure. This project is based on current study with Air force and Army in developing unique lightweight honeycomb structures for defense vehicles.

The primary AEG goals of this effort are following:

1. (1)
   Develop optimal lightweight composite honeycomb panel to provide a threshold level of energy absorption NIJ-IV level protection
2. (2)
   Develop an optimal lightweight composite with a aerial density equal to or less than 8.0 lb/sq.ft.
3. (3)
   Develop a sandwich structure consisting of microstructural element filled honeycomb with composite face sheets that reduces blast impact and also the mechanical integrity with flexibility. This goal will allow us to reduce the overall vehicle weight of the armor.

A honeycomb lattice with “waiting elements” filled with silicone gel has shown superior dissipation of impact energy by damage evolution mechanism. This non-monotonic dependence of the damage on the force leads to the greater than expected energy dissipation. This unique AEG honeycomb structure with “waiting elements” exhibit large pseudo-plastic deformations. AEG’s ballistic test results showed that this unique RCH sandwich structure has the potential to satisfy the performance and aerial coverage requirement for the armor.