1998 · 166 citations · 51 references
EngineeringAerospace EngineeringMechanical EngineeringAerodynamicsStructural DynamicsStructural EngineeringBeam AnalysisBending Of BeamsDeflection Of BeamsRotorcraft AerodynamicsRotorcraft StructuresStructural LoadsBeam ElementsBlade AerodynamicsBlade GeometryLarge Deflection Beam TheoryLarge Deflection Of BeamsRotor Blade LoadsRotor Blade Structural DynamicsRotor Stability
Recent advances in CAMRAD II dynamics models include refined beam geometry/material representations and a force‑balance approach for section load calculation. The study compares calculated beam deflections and rotor stability with experimental data, showing that a modest number of beam elements, rigid‑body motion, and a second‑order elastic model accurately capture large‑deflection behavior. The deflection method yields unacceptable structural load predictions, whereas the force‑balance method accurately predicts blade loads with few nodes.
Recent developments of the dynamics models for the comprehensive analysis CAMRAD II are described, specifically advanced models of the geometry and material for the beam component, and a force balance method for calculating section loads. Calculations are compared with measurements for beams undergoing large deflection. Bearingless rotor stability and bending loads calculations are compared with the results from a full-scale wind tunnel test. With a reasonable number of beam elements representing the rotor blade, any large deflection effects are captured by the rigid body motion (which is always exact), and a second-order model of the beam element elastic motion is adequate. The deflection method gives unacceptable results for the structural loads in practical cases, and even with uniform blade properties. The force balance method described here gives good results for blade load, without requiring a large number of nodes.
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