Patent attributes
A typical inventive embodiment describes a tubular shape and comprises a rigid outer layer, an elastomeric middle layer and a rigid inner layer. The elastomeric material is a strain-rate-sensitive polymer (e.g., polyurethane or polyurea) having a Young's modulus of approximately 700-1000 psi at 100% strain, and strong strain-rate-sensitivity in approximately the 103/second-106/second range. By the time that the projectile reaches the rigid inner layer, a projectile that impacts the three-layer system (commencing at the rigid outer layer) is structurally and kinetically diminished in its destructiveness by the rigid outer layer together with the elastomeric middle layer. Furthermore, the elastomeric middle layer becomes more rigid during a brief period in which it absorbs energy from the projectile, then again becomes elastic in a manner formative of a membrane covering the rigid inner layer. The elastomeric membrane tempers leakage if rupturing of the rigid inner layer has occurred.
