Study on cushioning characteristics of an airbag with self-adaptive variable-orifice vent

Airbag cushioning technology is an important landing attenuation method due to its lightweight nature and superior terrain adaptability. However, traditional airbags with fixed vent designs struggle to meet the demands of complex environments. To address these limitations, this study proposes a novel self-adaptive variable-orifice structure by designing fabric strength gradients around the vent. A drop-impact model for single-orifice configurations was established and experimentally verified. Parametric analysis of triple-layer fabric dimensions was conducted, while adaptive vent behavior and cushioning performance were evaluated across velocities (5.5-9.5 m/s) and payloads (300-2000 kg). Results showed that the tri-layer fabric enables tiered stress load-bearing, concentrating stress in the outer layer and upper vent region, achieving tear-resistant orifice expansion while reducing peak stress by 18% compared to unoptimized designs. Optimization of the tri-layer dimensions reduced the load platform's peak acceleration to 14.9g, representing a 45.8% decrease compared to the airbag with a fixed vent. This demonstrated that the proposed structure can adapt to low-payload (<1000kg) airdrop systems at 5.5–9.5 m/s, maintaining peak acceleration increases below 10%. For payloads above 1350kg, the drop velocity must be limited to ≤7.5 m/s due to vent congestion. This research confirms the adaptability of variable-orifice vent structures to diverse airdrop tasks, providing a theoretical foundation for self-adaptive impact protection systems.