Blast protection and dynamic response of airbags and foam/airbag composite structures: Mechanisms and structural parameter effects

The flexible composite structure based on airbags is a promising protective strategy, characterized by high mobility, rapid response, and the absence of secondary fragment hazards. In this study, using thin aluminum plates as the protected target, the blast protective performance of airbags and their composite structures was assessed and contrasted experimentally. The composite structures were composed of airbags and rigid polyurethane foam. A corresponding numerical model was established and validated to investigate the protective mechanism, deformation response, and protection efficiency of the airbags and their composite structures. Experimental and simulation results demonstrated that the airbag composite structure significantly reduced the permanent deflection and final internal energy of thin aluminum plates, and outperformed the single airbag structure. The protective mechanism of the airbags and their composite structures in attenuating the peak load and extending the load duration was clarified. Protection efficiency factors were defined based on the reduction in internal energy, while deformation factors corresponding to axial compression and lateral expansion were established for the airbags and their composite structures. The equal-efficiency protection curves were established by correlating deformation and protection efficiency factors, revealing their coupled relationship. The effects of structural parameters on the blast protection and dynamic response was studied parametrically, including the cushioning height, inflation pressure, membrane thickness, and foam thickness. Our study has investigated the blast protection and dynamic response of airbags and their composite structures, providing a foundation for the protection applications of flexible composite structures.