4. Appropriation methods

4.1 Introduction

Appropriation methods were developed as early as the 1960s by aircraft manufacturers, whose concern was to predict the flutter speed of an aircraft. This phenomenon of aeroelastic instability due to the coupling between the structure and the air can be predicted as soon as the modal characteristics of the structure are known, i.e. frequencies, damping and normalized eigenmodes. As conventional aircraft structures are generally non-linear, and safety issues are crucial in this field, it has been necessary to develop reliable methodologies adapted to this type of structure. In addition to the above-mentioned non-linear phenomena, the specific problems associated with aircraft testing are the size and mass of the structures, which pose suspension and instrumentation problems,...