Characterization of an Aero-Structural Interaction for the Hybrid Wing Body Center Section in Conceptual Phase Structural Sizing

摘要

The center section of a hybrid wing body (HWB) transport aircraft has the dual role of containing the pressurized passenger cabin and providing a significant percentage of vehicle lift. Since a vehicle of this type has never been in production, empirical models and historical data for conceptual phase sizing and performance evaluations do not exist. Therefore, early structural sizing for the HWB has shifted toward computational physics-based modeling to obtain initial weight estimates. These integrated computational environments implement assumptions consistent with the early phases of design, but may not capture important aero-structural interactions of the HWB centerbody. Because the upper skin of the centerbody experiences compression loads due to wing bending and out-of-plane pressure loads from the pressurized cabin, deflections of this structure have the potential to disrupt the flow over the center section. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept was developed to overcome challenges associated with this combined loading condition. However, system level assumptions for conceptual phase models of this technology result in more simplistic deflection distributions than in actuality. Therefore, structural sizing in the early design phases may not consider this interaction and could introduce risk to the aircraft program if it is constraining to the structural design. The approach taken in this paper is an attempt to identify the inconsistencies in the aero-structural interaction between low order models of the conceptual phase and higher order models used later in the design process. The NASA N2A HWB configuration is used as a baseline vehicle in the approach, and structural deflections at the centerline are taken from static linear elastic analyses and assessed in varying fidelity aerodynamics modles to determine the impact of the deflections on 2-D lift and drag coefficients as well as pressure coefficient distributions.