Substructure Mode Synthesis in the Prediction of Real Aircraft Vibration Modes

Abstract

© 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.This paper introduces a newapproach to modal synthesis by integrating simulations with realscale experiments. The technique partitions the complete aircraft structure into substructures: one representing the aircraft itself and others representing the hanging substructure that connects to the wing. A method is presented for imposing new frequencies on the vibration modes of the hanging substructure. Subsequently, experimentally obtained frequencies for the clamped substructure’s roll, yaw, and pitch vibration modes are imposed to evaluate the benefits in accurately predicting the overall aircraft behavior. As a result, the predicted frequency for the roll vibration mode of the substructure in the aircraft increased from 7.6 Hz to 11.9 Hz, while the result from real-scale ground vibration test was 11.6 Hz.