HAP-alpha: Model Updating Based on Ground Vibration Test and the Influence on Loads

Kurzfassung

This work presents the results of a ground vibration test of the highly elastic HAP-alpha (High Altitude Platform) and the subsequent model updating. The preliminary FE model was found to be sufficient for a meaningful aeroelastic design and a reliable structural sizing of this highly elastic aircraft. The steps for the model updating procedure, based on the experimental modal analysis, are described in detail. The agreement between the experimental and the updated FE modes is very good and all relevant modes are included. Good correlation was achieved for a frequency range of up to 15.0 Hz, which is more than sufficient for the intended aeroelastic applications. The required changes to the stiffness distribution are moderate (significant but not excessive) and can be explained in most cases.