Investigation of the cushioning characteristics and structural optimization of multi-connected airbags

With the increasing payload mass and growing environmental complexity in airdrop missions, traditional airbag systems face significant challenges in controlling overload, impact velocity, and rebound. However, research on the cushioning mechanism of the newly emerging multi-connected airbags remains limited. In this study, both theoretical and numerical approaches were developed to analyze the cushioning behavior of multi-connected airbags. The mechanisms of different components—including the main bag, auxiliary bag, and internal bag—were systematically investigated. The effects of operating conditions such as altitude and approach velocity on cushioning performance were explored. Furthermore, two optimization strategies for vent area design were proposed based on genetic algorithms: dynamic adjustment of vent areas under multiple conditions and global optimization of vent areas across all conditions. Results demonstrate that incorporating auxiliary bags can reduce impact velocity by up to 15.19% at an altitude of 4000 m and an approach velocity of 12 m/s. The internal bag reduces the impact velocity by increasing the maximum overload. Under the same conditions, it decreases the impact velocity by 5.93% and reduces the main-bag internal pressure by 9.27%, thereby alleviating the material load. Compared with the baseline model, the multi-condition dynamic vent optimization reduces the maximum overload of the platform by 63.95%, while the global optimal vent area design achieves a 50.88% reduction.