Flight Loads Prediction of High Aspect Ratio Wing Aircraft Using Multibody Dynamics

Abstract

A framework based on multibody dynamics has been developed for the static and dynamic aeroelastic analyses of flexible high aspect ratio wing aircraft subject to structural geometric nonlinearities. Multibody dynamics allows kinematic nonlinearities and nonlinear relationships in the forces definition and is an efficient and promising methodology to model high aspect ratio wings, which are known to be prone to structural nonlinear effects because of the high deflections in flight. The multibody dynamics framework developed employs quasi-steady aerodynamics strip theory and discretizes the wing as a series of rigid bodies interconnected by beam elements, representative of the stiffness distribution, which can undergo arbitrarily large displacements and rotations. The method is applied to a flexible high aspect ratio wing commercial aircraft and both trim and gust response analyses are performed in order to calculate flight loads. These results are then compared to those obtained with the standard linear aeroelastic approach provided by the Finite Element Solver Nastran. Nonlinear effects come into play mainly because of the need of taking into account the large deflections of the wing for flight loads computation and of considering the aerodynamic forces as follower forces.

Synthesis and Optimization of Mechanical Networks with Inerters in Landing Gear for Improved Landing Performance and Vibration Control at Touchdown Considering Airframe Flexibility

“…This approach, however, does not capture the aeroelastic effects resulting from the wing deformation at landing impact. In order to capture the aeroelastic effects at landing, aerodynamic strip theory [16,46] or a doublet lattice method [23] can be used in the simulation. However, in the short duration of landing impact, which is less than one second, Ijff concludes that the lift forces in a flexible aircraft will experience minor changes [14].…”

“…Various sources give example distributions of the cross-sectional properties for the equivalent beams of reference wings, fuselages and empennages [16,73,82] and their corresponding natural frequencies [83,82,46,17], with some expected values presented in Table 3.11. The properties include the second moments of area (I z ′ z ′ , I y ′ y ′ , and I y ′ z ′ ), the torsional constant,…”