Near-Real-Time Nonlinear Analysis of Free-Flying Flexible Aircraft on Modern Hardware Architectures

This paper explores the use of graphical processing units for computationally efficient aeroelastic dynamic analysis of free-flying vehicles. The numerical library JAX and an intrinsic description of the flexible aircraft dynamics are brought together into a highly vectorized codebase, thus enabling geometrically nonlinear simulations to run close to if not in real-time. The approach seamlessly integrates with conventional aeroelastic load packages to facilitate the analysis of complex aircraft configurations, which opens new possibilities for industrial-scale applications, including geometric nonlinearities. In addition, a multibody formulation is presented that shows the advantages of casting the nonlinear equations with velocities and strains as state variables. Verification studies on a double pendulum are first presented. The computational edge provided by the new implementation is then shown in a free-flying, very flexible structure in a vacuum that undergoes strongly coupled rigid body and elastic deformations. Finally, the aeroelastic response of an industrial-scale aircraft configuration is studied. Results include a comparison of the trim equilibrium against linear simulations, a recovery of the full three-dimensional geometry, and the response of the trimmed aircraft under 1-cos gusts. Wing loads are finally evaluated, confirming that linear assumptions may be nonconservative for high-aspect-ratio wing aircraft.