An Integrated Three-Dimensional Aeromechanics Analysis of the NASA Tilt Rotor Aeroacoustic Model

This paper presents the first use of integrated three-dimensional (3D) aeromechanics modeling, defined as a coupling of 3D solid finite element analysis structural dynamics with 3D computational fluid dynamics (CFD), to study a real rotor, the NASA Tilt Rotor Aeroacoustic Model (TRAM) proprotor. The goal is to demonstrate the development of this new methodology and assess its capabilities. The X3D structural dynamics solver is coupled to Helios for this analysis, which is the first coupled CFD/computational structural dynamics analysis of a proprotor in edgewise flight. Airloads predictions show that trends are well captured, though there are errors in the magnitude of vortex interaction peaks. Blade loads predictions capture measured trends at low thrust, but at high thrust 3/rev flap and lag bending is not captured. These discrepancies are attributed to a lack of accurate composite material properties. Detailed 3D stress fields are studied at several azimuths, revealing complex localized stress patterns.