Numerical simulation of the ground inflation and lifting process of a non-formed stratospheric airship

The release process of non-formed stratospheric airships, during which complex changes occur in the airship's morphology and attitude, presents a certain degree of risks and directly affects flight mission safety. However, this process has not been adequately investigated because of its complexity and inherent uncertainties. In this study, a fluid-structure coupling method that combines the finite element method and smooth particle hydrodynamics was developed to solve the transient ground inflation and lifting processes of a non-formed airship. The numerical simulation results show that the airship head gradually expands to achieve the designed profile following a rapid attitude transition during the initial inflation stage, whereas the part between the head and the folded region contracts. The folded edges remained in place until they were inflated, with the tops of these edges exhibiting the highest stress levels. During the inflation process, when the local weight of the solar panels was neglected, no interference occurred in the uninflated areas; however, specific folds may lead to the deformation of the solar panels. To prevent interference with other subsystems, the propulsion system should be installed within an approximately triangular region near the airship head. Additionally, the airship’s lift increases almost linearly with gas filling, although fluctuations in lifting speed were observed. The random wind field, identified as the primary source of uncertainty, caused limited fluctuations in both the lifting height and rotation of the airship. The numerical results corresponded with the experimental results, indicating that the ground non-formed inflation is stable under light wind conditions.