Aeroelastic Simulation of Flexible Membrane Wings based on Multibody System Dynamics

The chapter describes a simulation framework for flexible membrane wings based on multibody system dynamics. It is intended for applications employing kites, parachutes or parasails with an inflated tubular support structure. The tube structure is discretized by an assembly of rigid bodies connected by universal joints and torsion springs. The canopy of the wing is partitioned into spanwise sections, each represented by a central chordline which is discretized by hinged rigid line elements. The canopy is modeled by a crosswise arrangement of spring-damper elements connecting these joints. The distributed loading of the wing structure is defined in terms of discrete aerodynamic forces. Acting on the joints, these forces are formulated per wing section as functions of local angle of attack, airfoil thickness and camber. The presented load model is the result of a comprehensive computational fluid dynamic analysis, covering the complete operational spectrum of the wing. The approach captures the two-way coupling of structural dynamics and aerodynamics. It is implemented as a toolbox within the commercial software package MSC ADAMS. For validation, the model is compared to existing wind tunnel data of a similar sail wing.