An approach for design and analysis of composite rotor blades.

Abstract

The advent of tilt rotor technology asks for rotors that have different twist and RPM requirements in hover and in forward flight to optimize for operational conditions. In order to get an assessment of the capabilities to fulfill these requirements this report presents a mapping of twist angle variation as a function of RPM and laminate orientation. The basic laminate for the six models as well the D-shape spar that represents the structurally active part of the blade is assumed to be constant (0°/90°/0°/90°/90°/0°) . This six layer cross ply laminate is chosen as it provides the necessary extension-twist coupling without a hygrothermally induced twist that is highly undesirable. The couplings and trends in the models are visualized in carpet plots, one for each model, in an attempt to establish a method to answer the basic question of the magnitude of twist angle available due to a particular geometry, material and load system.