Professor Gaëtan Kerschen,
University of Liège, Belgium,
will give the lecture
"Natural Frequencies and Normal Modes of Nonlinear Aerospace Structures"
Abstract:
The concept of natural frequency and normal mode is central in the theory of vibratory systems. Besides their obvious physical interpretation, the normal modes have interesting mathematical properties such as orthogonality and superposition. They are therefore used in structural dynamics for various purposes including model reduction, model validation and structural health monitoring. One important assumption underlying classical modal analysis is that the considered structure behaves linearly in the regimes of motion of interest.
Because nonlinearity is pervasive in engineering structures (e.g., gaps and friction), a rigorous, yet practical, framework for modal analysis of nonlinear systems will be presented in this talk. This framework will be used to explain nonlinear dynamical phenomena with no linear counterparts, including interactions between widely-spaced modes and mode bifurcations. It will then be applied to real-life aircraft and spacecraft for getting a profound understanding of their nonlinear dynamics. Finally, the talk will discuss how nonlinearity can be exploited for enhancing the performance of engineering structures.