Solar Impulse - Ground vibration testing and finite element model validation of a lightweight aircraft

This paper addresses the challenges in ground vibration testing and in finite element model updating of superlight aircraft structures where the influence of the surrounding air on experimental modal data is no longer negligible. This so called apparent mass effect can lead to complex experimental mode shapes and to biased estimates for experimental damping ratios and experimental eigenfrequencies obtained from ground vibration test. It is essential that the effect of surrounding air on experimental modal data is properly understood to detect finite element model parameters that need to be adjusted while at the same time to avoid adjustment of unreasonable parameters in model updating.