Session: 01-01-02: General Topics of Aerospace Structures

Paper Number: 110857

110857 - Energy Flow Configuration and Aeroelastic Stability of Flying Wing Aircraft 

This presentation sheds light on the relationship between energy flow configuration and the aeroelastic stability of flying wing aircraft. Our mental view is that the energy flow configuration is the configuration of the flow of internal stresses, leading to structural instability if it experiences strangulation. In this study, we use the concept of constructal law as the foundation of this physics to explain how engine placement and flow of stresses affect the aeroelastic flight envelope of flying wing aircraft. The stress distribution through the swept and curved wings reveals that the flutter instability occurs at a higher speed when stress strangulation is avoided. It is demonstrated that the inflected wing aircraft is more stable than the non-infected wing due to its freedom to morph to accommodate the flow of stresses with less strangulation. In addition, when the stresses flow smoothly through the cross-section of a wing, the flutter instability occurs at a higher speed. Ultimately, the authors intend to present the application of the concept of the flow of stresses in aircraft to curious readers to encourage the use and development of this approach to accelerate the evolution of aerospace vehicles.

I. Swept vs. curved wing The differences in flutter speeds of a swept and curved wings aircraft are addressed using the constructal law and the concept of the flow of stresses. This concept is used to explain why the flutter speed of the swept flying wing is higher than curved wing. The results reveal that the stress distribution is independent of the trim state condition and the internal force distribution. Figure 1 demonstrates that the stress distribution through the wing is similar in both configurations, whereas the magnitudes of the stresses change. The study of aeroelastic instability through the lens of the flow of stresses revealed that the design of flying wing aircraft does not evolve toward a curved wing since swept wing fulfills the criteria for an improved aeroelastic flight envelope; see Fig. 1. II. Inflected wing: The same analogy was invoked to show why inflected flying wing aircraft achieves higher flutter speed. The relation between the ability to morph the wing and the aeroelastic stability (flutter speed) was studied. It is demonstrated that inflected wings have the capability to substantially improve the stability of a flying body. We investigated two types of wings; inflected and non-inflected. The presented results in Fig. 2 show that the inflected wing has a more uniform stress distribution throughout the I. Swept vs. curved wing The differences in flutter speeds of a swept and curved wings aircraft are addressed using the constructal law and the concept of the flow of stresses. This concept is used to explain why the flutter speed of the swept flying wing is higher than curved wing. The results reveal that the stress distribution is independent of the trim state condition and the internal force distribution. Figure 1 demonstrates that the stress distribution through the wing is similar in both configurations, whereas the magnitudes of the stresses change. The study of aeroelastic instability through the lens of the flow of stresses revealed that the design of flying wing aircraft does not evolve toward a curved wing since swept wing fulfills the criteria for an improved aeroelastic flight envelope; see Fig. 1. II. Inflected wing: The same analogy was invoked to show why inflected flying wing aircraft achieves higher flutter speed. The relation between the ability to morph the wing and the aeroelastic stability (flutter speed) was studied. It is demonstrated that inflected wings have the capability to substantially improve the stability of a flying body. We investigated two types of wings; inflected and non-inflected. The presented results in Fig. 2 show that the inflected wing has a more uniform stress distribution throughout the

Presenting Author: Pezhman Mardanpour Florida International University

Presenting Author Biography: Dr. Mardanpour is an associate professor at Florida International University. He received his Ph.D. and M.S. from the School of Aerospace Engineering at the Georgia Institute of Technology. Under the supervision of professor Dewey H. Hodges, he became an expert in Hodges’s nonlinear composite beam theory as well as the aeroelastic design of UAVs.

A regular contributor to the Journal of Aircraft, the Journal of Fluids and Structures, the Journal of Nonlinear Dynamics, and the Journal of Vibration, Sound and Control, Dr. Mardanpour is a professional member of American Institute of Aeronautics and Astronautics (AIAA), the American Society of Mechanical Engineering (ASME), and the American Physics Society (APS).

Authors:

Mojtaba Moshtaghzadeh Florida International University
Pezhman Mardanpour Florida International University