SIMILARITY PARAMETER ANALYSIS OF AEROELASTIC MODEL FOR NON-RIGID STRATOSPHERIC AIRSHIP

For the wind tunnel tests to investigate the aeroelastic characteristics of non-rigid stratospheric airships, scale models are needed to replace the full-scale model due to its large size. Whether the test results of the scale models can accurately predict the displacement response of the prototype structure is directly correlative to the similarity design. In this paper, a non-rigid stratospheric airship was taken as the prototype object and the similarity criterions of the model were deduced based on a dimensional analysis. The finite element model of the non-rigid stratospheric airship was established, and the natural vibration and wind-induced responses of scale models with different similar ratios were analyzed. The corresponding vibrational frequency and displacement response were obtained. The influence degrees of each similarity criterion on vibrational frequency and displacement response were statistically determined. The similarity deviations that do not meet the similarity requirements and have a greater influence degree were evaluated, and the corresponding compensation corrections were obtained. The study demonstrates that the similar deviation of wind velocity can be ignored. The similar deviation of membrane surface density on the displacement response can be ignored. The similar deviations of membrane tensile stiffness and differential pressure appreciably affect the vibrational frequency and displacement response.