Incorporation of VABS Composite Beam Sectional Analysis Into a Comprehensive Rotorcraft Analysis Code with Application to Aeroelastic Tailoring

The compatibility between a composite beam cross-sectional analysis based on the variational asymptotic approach, and a helicopter rotor blade model which is part of a comprehensive rotorcraft analysis code is examined. It was found that the comprehensive analysis code can be upgraded with the finite element cross-sectional analysis code VABS (Variational Asymptotic Beam Sectional Analysis) without modifying the existing computer code structure. The new rotor blade model accounts for arbitrary cross-sectional warping, in-plane stresses, and moderate deflections. The composite rotor blade model was validated against experimental data and various rotor blade analyses by examining displacements and stresses under static loads, as well as aeroelastic stability of a composite rotor blade in hover, and forward flight vibratory hubloads of a four bladed composite rotor. Furthermore, the upgraded analysis code was used to examine the effectiveness of aeroelastic tailoring for vibration reduction when using aerodynamic models of varying sophistication, and to study the effects of aeroelastic tailoring on vibration and strain levels when employing active vibration reduction.