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 University of Michigan Variational Asymptotic Beam Sectional analysis code (UM/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, bringing both his expertise and the latest version of the UM/VABS code 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 is flexible and modular, so that individual codes can be replaced without major software development effort. The development will be incremental in four major software builds and releases in Phase II. The primary piece of original software to be developed is IXGEN, the Intelligent Cross Section Generator. This is a suite of codes that let the user define a rotor blade or wing by its primary design features and their driving parameters. IXGEN translates this parametric information into a UM/VABS model for each cross section considered.