Static Aeroelastic Analysis of Thin-Film Clamped Ballute for Titan Aerocapture

Abstract

Many authors have shown the potential mass savings that a ballute can offer for both aerocapture and entry. This mass savings could enhance or even enable many scientific and human exploration missions. Prior to flight of a ballute several technical issues need to be addressed, including aeroelastic behavior. This paper begins to address the issue of aeroelastic behavior by developing and validating the Ballute Aeroelastic Analysis Tool (BAAT). The validation effort uses wind tunnel tests of clamped ballute models constructed of Kapton supported by a rigid nose and floating aft ring. Good correlation is obtained using modified Newtonian aerodynamics and non-linear structural analysis with temperature dependent material properties and thermal expansion. BAAT is then used to compute the deformed shape of a clamped ballute for Titan aerocapture in both the continuum and transitional regimes using impact method aerodynamics and direct simulation Monte Carlo. NOMENCLATURE C p-Pressure coefficient Kn-Knudsen number nbmin-Minimum number of flow cells on the body q-Dynamic pressure (Pa) γ-Ratio of specific heats

Aeroelastic Design Considerations of a Clamped Ballute for Titan Aerocapture

“…8 The transitional regime uses a bridging function to determine surface pressures. 6 The low-fidelity methods used here are between 4 and 35 times faster in the continuum and rarefied regimes respectively. 9…”

“…This research uses the Ballute Aeroelastic Analysis Tool (BAAT) 6 to determine the static deformed shape of a ballute at Titan along an aerocapture trajectory using impact method aerodynamics. Trends of interest to a vehicle designer (drag, deformation, and stress level) will be presented.…”

Development of a Fluid-Structure Interaction Framework Using Unstructured Cartesian CFD Methods

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A Loosely Coupled Analysis of the Fluid-Structure Interactions for Inflatable Aerodynamic Decelerators

“…Tanner 7 presented the follow-on FSI work for these tension cone tests. The structural dynamics was computed using LS-DYNA, based on the previous studies by Rohrschneider 3 and the CFD was computed using FUN3D, a Navier Stokes solver written at NASA Langley. This work provided a detailed set of LS-DYNA validation cases, which further proved its capability.…”