An Overview of the NASA High Speed ASE Project: Aeroelastic Analyses of a Low-Boom Supersonic Configuration

Abstract

An overview of NASA's High Speed Aeroservoelasticity (ASE) project is provided with a focus on recent computational aeroelastic analyses of a low-boom supersonic configuration developed by Lockheed-Martin and referred to as the N+2 configuration. The overview includes details of the computational models developed to date including a linear finite element model (FEM), linear unsteady aerodynamic models, structured/unstructured CFD grids, and CFD-based aeroelastic analyses. In addition, a summary of the work involving the development of aeroelastic Reduced-Order Models (ROMs) and the application of the CFL3D-ASE code that enables the inclusion of a control system within the CFL3Dv6 CFD code is presented.

Ongoing Fixed Wing Research within the NASA Langley Aeroelasticity Branch

“…Stress, buckling, and manufacturing constraints are all enforced during the optimization process, and the final structure is composed of 55% composites, 26% aluminum, 16% titanium, and 3% steel. Linear flutter results (doublet lattice method for subsonic flow, and the oscillatory lifting surface theory ZONA51 for supersonic), for a range of conditions including with/without fuel and symmetric/anti-symmetric mode shapes, indicate [27] that flutter does not occur within the flight envelope (including a 15% speed margin) for this configuration. However, linear techniques have been known to be non-conservative in the transonic range (the limits of this range are not clear for this non-traditional configuration), necessitating the use of higher-fidelity CFDbased tools.…”

“…The highly detailed structural model of the vehicle (described in Ref. [27], and consisting of skins, ribs, spars, bulkheads, and longerons) was sized by Lockheed Martin across a variety of maneuver, gust, and landing load conditions. Stress, buckling, and manufacturing constraints are all enforced during the optimization process, and the final structure is composed of 55% composites, 26% aluminum, 16% titanium, and 3% steel.…”

Computational Aeroelastic Analyses of a Low-Boom Supersonic Configuration

“…The ultimate goal of this development is to be able to determine if the airframes flexibility has an effect on the thrust dynamics of the propulsion system, coupling back to the airframe flexibility modes as a closed loop system, in order to study performance like vehicle stability and ride quality. This paper will address results from prior publications [10,11] as well as recent accomplishments. The paper begins with a description of the Lockheed-Martin N+2 configuration followed by a description of the structural sizing and analysis leading to an FEM.…”

A Status Review of the Commercial Supersonic Technology (CST) Aeroservoelasticity (ASE) Project

“…The unique structural configuration of supersonic aircraft combined with nonlinear aerodynamics and rigid-body effects often results in highly complex nonlinear aeroelastic/flight This paper presents a status update on this computational effort [1][2][3]. This includes a brief description of the N+2 configuration, the finite element model (FEM), computational aeroelasticity solutions, and sonic boom propagation results that include static aeroelastic effects.…”