Generalized Timoshenko and Vlasov Theories for the Oblique Cross-Sectional Analysis of Rotor Blades

An important aspect of rotor blade structural and aeroelastic analyses is the cross-sectional analysis, i.e., the step that generates the blade section properties and recovers 3D stress, strain and displacement. Although there exist several section tools of repute, they suffer from a shortcoming that the reference section has to be perpendicular to the reference line. Therefore, should a user possess the 3D material and geometric properties of a nonorthogonal or oblique section, a significant effort needs to be undertaken in order to get those of the corresponding orthogonal section. The present work addresses this shortcoming by incorporating an oblique cross-sectional analysis model into both Generalized Timoshenko and Generalized Vlasov models of the well known tool VABS. The obliqueness model of VABS is then used with a geometrically exact nonlinear beam formulation to extract the static and dynamic results for beams of various cross sections, through which thorough verification and validation are undertaken. Excellent agreement is observed with results from 3D finite elements and experiments; a fact which must be emphasized given the user-friendly and cost-effective nature of VABS.