Composite Rotor Blade and Wing Structural Design Tool

Aeroelastic effects are significant design drivers in rotorcraft design. Typically, detailed structural information of the rotor blade necessary to determine its cross-sectional mass and stiffness properties is not available early on in the design process, especially for complex composite blades that are being employed in modern rotor systems. Therefore, high-fidelity aeroelastic analysis is usually not done until late in the rotorcraft design process, when changes to the design are difficult and costly to implement. Advatech Pacific proposes to address this shortcoming through the development of an integrated rotor blade design environment, where the blade cross sectional properties are calculated by the Variational Asymptotic Beam Sectional analysis code (VABS). This approach combines the comparatively low run times of a beam structural analysis desired for a preliminary-level design tool with the high fidelity rotor blade cross sectional information typically associated with a 3D finite element approach. Overall rotorcraft design and blade aeromechanical analysis is provided by the Rotorcraft Comprehensive Analysis System (RCAS). The original developer of VABS, Dr. Carlos Cesnik, is part of the Advatech Team, giving us a significant head start by bringing both his expertise and the latest version of the VABS code, UM/VABS, to the project. In addition, Mr. Robert Loftus, currently a Technical Fellow at the Boeing Company (formerly McDonnell Douglas Helicopters) and IPT Lead for the new composite main rotor blade design and development for the AH-64D Apache Attack Helicopter, will be providing practical blade design expertise. The proposed design environment will be flexible and modular, so that individual codes can be replaced without major software development effort, should that be desired in the future. The development will be incremental, with Phase I of the SBIR effort focusing on proving out the envisioned architecture.