Confined Inflatable Structures: From Experiments to Simulations

Abstract

The implementation of large-scale inflatable structures is now a viable alternative for sealing of segments of transportation tunnel in emergency situations. The rapid deployment of one or more inflatables can prevent the propagation of flooding, noxious gasses or smoke until more permanent containment and repair measures can be put into place. In such applications, the inflatable structure is prepared for placement, either permanently or temporary, and left ready for deployment, inflation, and pressurization when needed. The level of sealing effectiveness depends on the ability of the inflatable structure to deploy and self-accommodate, without human intervention, to the intricacies of the perimeter of the conduit being sealed. Once deployed, inflated and pressurized, the inflatable has to remain stable during the containment of the threat. Extensive testing at multiple scales was completed in the past years to evaluate and fine tune the functionality of the inflatable structure and associated subsystems. However, testing multiple scenarios and different configurations of the system can be very expensive and time-consuming, and, therefore, the development and calibration of finite element simulations of the system become imperative to predict possible outcomes and therefore, minimize the need for physical testing. This work presents an overview of the development of finite element simulations of the deployment and inflation of a full-scale inflatable prototype placed within a tunnel section. Techniques developed experimentally served as the basis for the development of computational models that can simulate different stages of folding, placement, initial deployment and full inflation. The good level of correlation between experimental and simulation results in terms of deployment dynamics and levels of contact demonstrated that the proposed modeling strategy could be used as a predicting tool for other tunnel shapes and sealing configurations.