Simulation of Controlled Deflation, Folding and Inflation of Large-Scale Confined Inflatable Structures

Transportation tunnels have been identified as particularly vulnerable to different threats such as propagation of toxic gases, or smoke originated by human activities, or flooding originated by extreme climatic events such as hurricanes and severe weather. The implementation of large-scale inflatable structures to plug specific locations of the tunnel system to minimize the consequences of the propagation of disastrous events is now possible. However, even with the successful results obtained in experimental evaluations, the development of simulations that can predict the performance of the inflatable in advance to reduce the number of experimental iterations is still essential. The finite element simulations presented in this work are focused on reproducing deflation, folding, and placement procedures for deployment and inflation of a large-scale inflatable from the ceiling of a tunnel segment. The results of the simulations showed that a very compact shape can be achieved by implementing a controlled deflation and a combination of translational and rotational planes to reach the final folded shape. Moreover, the implementation of passive restrainers to control the movement and release of the membrane during different stages of the simulations contributed to reach higher levels of local conformity of the inflatable to the tunnel perimeter, which also translated in a better sealing capacity of the inflatable to the tunnel profile.