A multi-body approach for modelling manoeuvring aeroelastic aircraft during preliminary design

Abstract

During preliminary design, aircraft are described with a limited level of detail, the focus being on rapid investigation of a large number of cases and quickly changing configurations and parameters. Therefore in the majority of cases, dynamic aeroelastic deformations are neglected. In this paper, an approach to modelling aeroelastic aircraft based on multi-body dynamics at the preliminary design stage is presented. The elastic structure is discretized by means of rigid bodies and connected by rotational springs to account for wing bending and rotational stiffness. For the aerodynamics, the strip theory, corrected for the influence of a finite wing, is used. Flight mechanics are included via library elements that describe the degree of freedom between the (inertial) reference system and the moving airframe. The complete model allows a free-flight simulation of the aircraft, including trim and manoeuvres. The evaluation puts special emphasis on flight load calculation. Scenarios include free flight, a pull-up, and investigations of changes in ground loads due to changes in structural elasticity.