Tough, Impact-Resistant Composite Structures for Lightweight Airborne Laser Subsystem

"The Airborne Laser (ABL) system is being developed using a Boeing 747 aircraft platform for use in missile defense systems. Improved missile defense effectiveness and ABL system performance such as range are improved if the platform and ABL system weightcan be reduced. Current ABL technology demonstration systems and subsystems, such as the ABL-Pressure Recovery Subsystem (ABL-PRS) use heavier materials such as titanium. Weight reductions using advanced composite materials can be substantial, withestimates of 5,000 pounds savings for the ABL-PRS alone. A key problem in the wide-spread insertion of composites in the man-rated ABL system platform is the lack of data base and thus very conservative design knockdown factors used for composites toensure positive design margins are achieved on these components for uncertainties such as impact resistance due to mechanical abuse during installation and maintenance of composite components. A unique composite concept is proposed for tough, impactresistant and lightweight ABL composite components. The concept uses high strain-to-failure carbon fiber reinforced composites as surface laminates, to provide impact resistance, in conjunction with higher modulus and higher temperature resins, such asM40J/epoxy and M40J/bismaleimide material systems, to provide high stiffness and strength. This concept will decrease the design knockdown factors associated with impact damage during installation and ma