UC San Diego
Blast damage mitigation of steel structures from near- contact charges
- Author(s): Wolfson, Janet Crumrine
- et al.
A series of experiments have been performed on a built-up cellular steel structure to determine the structural response of the system when subjected to an explosive load at close range. Initial full scale field tests demonstrated how the structure reacted under an extreme loading event; specifically, in the failure of the bolts and support structure, and the formation of flyer plates. Flyer plates are formed out of the support steel of the structure. They can range in size from several inches square to several feet square depending on the size of the charge and standoff. These flyer plates, if unimpeded, can travel at extremely high velocities; they will then impact additional steel plates forming secondary flyer plates, which can cause significant damage to the entire structure. Laboratory tests were performed on structural components, plates and bolts, to evaluate their failure mechanisms. Comparisons were made between the type of bolts used and plate thicknesses in developing behavior phenomena. Strain rate data was gathered that can be used to improve existing material behavior. This data reflects overall system behavior as opposed to component behavior. Based on the knowledge gained from these experiments a new retrofit technique was developed that can mitigate damage during an extreme event. The new so-called Kinetic Energy Defeat Device (KEDD) utilizes non-viscous liquids in a periodic array to redirect the kinetic energy of a projectile through the formation of high speed jets. This re-direction of energy can slow the velocity of the incoming projectile, thereby, limiting the damage to the structure. Full scale and scaled field tests, along with laboratory tests have been performed to determine the effectiveness of this device. Tests with and without the KEDD system have been compared evaluating the type of failure that occurs and the speed at which the projectiles travel