Applied Aircraft Aeroelasticity

This course is a follow-up course of AE4ASM506 Fundamentals of Aeroelasticity. This course presents three more advanced topics in aeroelasticity: 1) nonlinear aeroelasticity; 2) flexible aircraft flight dynamics; 3) panel methods. Understanding the contents of this course will prepare the student for the design of future aircraft configurations beyond the currently established aircraft concepts.

Part One: Nonlinear Aeroelasticity

Nonlinear aeroelasticity represents the first topic that we are going to address in this course. Nonlinearities in aeroelastic systems are important to consider since their introduction can significantly change the response and stability characteristics of the initial underlying aeroelastic system. Hence they can represent an important safety hazard that must be addressed.

Nonlinearities in convention aeroelastic systems originate from three main sources: structures, free-play in the actuation mechanisms, and aerodynamics. Each of these will be addressed in the following lectures.

Part Two: Flexible Aircraft Flight Dynamics

For a long time in the history of aviation, flight dynamics and aeroelasticity have been seen as two independent disciplines. The former focuses on the translational and rotational motions of a rigid body, while the latter mainly focuses on the interactions between structural vibration dynamics and aerodynamics of a clamped wing. However, as aircraft structure is getting lighter and more efficient, the structural flexibility is increasing. This trend is obscuring the boundary between "low-frequency" rigid-body flight dynamics and "high-frequency" structural dynamics, which creates a new interdisciplinary area named flexible aircraft flight dynamics. The importance of this area has been demonstrated by the loss of NASA - Helios Mishap. We will use two lectures to show you the fundamentals of flexible aircraft flight dynamics. 

Part Three: Panel Methods for Aerodynamics

One of the key aspects of every aeroelastic analysis is the calculation of aerodynamic loads generated by the lifting surfaces due to their deformation. This is a challenging task due to the complexity of the Navier-Stokes equations governing the flow behaviour. As a result, one needs to resort to simplifications and empirical relations for flow behavior. The simplest method is the strip theory which we have used extensively when studying the typical section. However, the main disadvantage of the strip theory is that it doesn't naturally account for the 3D effects such as the finite span of the wings, and the presence of multiple lifting surfaces. This disadvantage can be mitigated by the panel methods which are based on linear potential aerodynamic theory. We will study these methods in this module.