Vabs: A New Concept for Composite Rotor Blade Cross-Sectional Modeling

A general framework for modeling composite rotor blades is presented. This framework extracts from a three-dimensional elasticity formulation two sets of analyses: one over the cross section, providing elastic constants that can be used in a suitable set of beam equations, and the other the beam equations themselves. The cross-sectional analysis, along with the accompanying engineering software (VABS), provides an accurate beam representation of the blade structure, allowing a designer to take advantage of composite materials when designing rotor blades. VABS is able to take into consideration anisotropic, nonhomogeneous materials and to represent general cross-sectional geometries, requiring neither the costly use of 3-D finite element discretization nor the loss of accuracy inherent in any simplified representation of the cross section. Results obtained from analysis of a variety of composite beams are presented. The generality of the method and accuracy of the results should increase confidence at the design stage that the structure will perform as expected and, consequently, should lower costs from experimental tests and further adjustments.