MULTIFUNCTIONAL STRUCTURE-BATTERY MATERIALS FOR ENHANCED PERFORMANCE IN SMALL UNMANNED AIR VEHICLES

Aircraft design and manufacturing have been in a state of constant technological evolution over the last 100 years. Considerable effort has been focused on improving performance, durability, and reliability, and lowering costs. This is being accomplished today using cutting-edge design methodology that incorporates multidisciplinary design optimization of complex systems in place of older methods that independently optimized local subsystems and iterated between designs to satisfy global design constraints. Air vehicles are designed to move payload between two points, hence increasing the payload capacity or increasing the flight time endurance or range are important system-level goals in the design process. For winged aircraft, a large percentage of total weight is taken up by the structure (~37%) and fuel (~34%) (Thomas et al., 2002). Decreasing the weight of these subsystems or increasing the fuel weight fraction can improve aircraft performance, and this can be accomplished through structure-power multifunctionality. This abstract reports on the design and use of a multifunctional structure- battery (power) material to increase the flight endurance time of a small electric-propelled unmanned air vehicle (UAV). Flight endurance time is related, in Eq. (1), to the available battery energy, subsystem weights, and aerodynamic parameters. As can be seen from this equation, modifications in the available battery energy or sub-system weights (structure and battery) will affect system performance. Increases in the flight time are sought through a reduction of redundancy between the structure and battery subsystem materials and functions (shape and power). We can accomplish this by using a multifunctional structure-battery material that stores electrical energy while a carrying part of the mechanical load.