Modal Parameters of Light Aircraft Wing

Abstract

The main aim of this work is to extract modal parameters of a light aircraft wing. Modal parameters like modal frequency, modal damping and mode shapes characterise the dynamic response of a particular structure and can be used for determining an excess wing flexure as well as the long-term effect of fatigue.

For the experimental part the response of the Piper Warrior II was recorded during ground runs. A set of temporarily attached accelerometers was used to record the response of the wing and the signals were recorded. Subsequently a Frequency Response Function was generated in the post-processing stage, which resulted in determining the first and second bending modes as well as the first twisting mode. A Finite Elements Model was applied to validate the results.

Due to the limitations of the taxiing speed the method cannot excite higher frequency modes; however the findings can find numerous applications in real time in-flight flexure monitoring.