Deep Penetration in Aerospace Composite Materials Using Near-Infrared Laser Radiation

Abstract

Previous work on lethality against composite material targets considered only surface deposition of laser energy, with lethality achieved via target penetration or material removal by ply separation, delamination, and blow-off in high-speed airflow. To produce lethal effect in a militarily relevant timescale, typically on the order of seconds, requires laser irradiance in the range of ten to a few hundred kilowatts per cm 2 . This Feasibility Study discovers that volume heating, either by direct in-depth absorption of laser energy, for example in near-infrared (IR) laser irradiation of translucent fiberglass composite, or by rapid conduction of surface-deposited energy as in the case of opaque carbon composite, can induce failure under load in seconds by softening the resin matrix at irradiance less than 100 W/cm 2 -one to three orders of magnitude lower than the intensity required to produce lethal effect by target penetration or material removal.