TIP LOSS AND BLADE STRIKE SIMULATIONS USING DYSCO

A modeling technology has been developed to evaluate the damage tolerance of rotor-craft dynamic systems and has been incorporated into an interactive computer program called DYSCO (Dynamic System Coupler). The motion of a rotorcraft can be simulated with changes in control inputs, physical and geometric properties, and applied loads imposed at any instant. Changes to single or multiple blades of an aeroelastic rotor representation due to ballistic damage or other anomalies can be made. The feasibility of a strike-tolerant main rotor blade was investigated; a blade striking an obstacle would cause a frangible blade tip to separate from the blade, preventing impact loads from being transmitted to the blade root and hub. The loss of one blade tip from a teetering rotor and a blade strike were modeled. The effects on the system dynamic response, corresponding blade loads, and control inputs were demonstrated. Using the coupling procedure unique to DYSCO, forcing functions can be applied at any point or points along a blade, allowing precise definitions of the impact function associated with a strike to be implemented.