A NEW METHODOLOGY TO PREDICT AND OPTIMIZE ROTORCRAFT STRUCTURAL LOADS/WEIGHTS USING FINITE ELEMENT METHOD

A new methodology is developed to automate loads/weights development and optimization procedures to support a more optimized structural design at a preliminary design phase or DEM/VAL (Demonstration and Evaluation) effort. This system will provide the structures and weight engineers with a tool to rapidly predict the initial sizes, weights, internal loads, and materials of the structure prior to the start of the detail design of the aircraft. The system needs only data and engineering drawings normally produced at the preliminary design phase. Based on the design criteria, the rotorcraft weights are generated using semi-analytical and empirical weight prediction equations. The airframe structural weight is optimized using fully stressed design criteria. The weight due to fasteners, splices, honeycomb panels, surface coatings, and fittings is computed using empirical equations based on the historical data and added to the optimized structural weight to get a more realistic structural weight. A metallic rotorcraft, Bell Model 222B was used for validation purpose. This paper presents the overall development of this methodology.