Title:
Dynamic Stability Analysis of Blunt Body Entry Vehicles
Through the Use of a Time-Lagged Aftbody Pitching
Moment
Dynamic Stability Analysis of Blunt Body Entry Vehicles
Through the Use of a Time-Lagged Aftbody Pitching
Moment
Author(s)
Kazemba, Cole
Advisor(s)
Braun, Robert D.
Editor(s)
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Abstract
This analysis defines an analytic model for the pitching motion of blunt bodies during atmospheric entry.
The proposed model is independent of the pitch damping sum term which is present in the standard
equations of motion, instead using the principle of a time-lagged aftbody moment as the forcing function for
oscillation divergence. Four parameters, all with intuitive physical relevance, are introduced to fully define
the aftbody moment and the associated time delay. It is shown that the dynamic oscillation responses typical
to blunt bodies can be produced using hysteresis of the aftbody moment alone. The approach used in this
investigation is shown to be useful in understanding the governing physical mechanisms for blunt body
dynamic stability and in guiding vehicle and mission design requirements. A case study using simulated
ballistic range test data is conducted. From this, parameter identification is carried out through the use of a
least squares optimizing routine. Results show good agreement with the limited existing literature for the
parameters identified. The model parameters were found to be accurate for a wide array of initial conditions
and can be identified with a reasonable number of ballistic range shots and computational effort.
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Date Issued
2012-10-05
Extent
Resource Type
Text
Resource Subtype
Masters Project
Rights Statement
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