Inflatable Shells: Pressurization Phase

Inflatable shells are extremely thin shells that undergo considerable displacement because of the action of internal pressure. Their behavior can be divided into three phases. The first phase is the unfolding of the shell into its initial unstrained shape from its compact configuration. The second phase is the inflation of the shell into a desired final configuration. The third phase of the behavior that in which the shell is fully inflated and subjected to external loads. The second phase is studied in detail, and a general nonlinear theory is presented for a shell of arbitrary shape. Because the desired shell shape corresponds to the loaded shell, the deformed middle surface is used as the reference surface for the stresses and displacements of the deformed shell. The general theory for the second phase is then specialized for shells of revolution loaded axisymmetrically. A closed-form solution for the force resultants is given. A perturbation method of solution is derived for the displacements. A sample problem is used to demonstrate the effectiveness of this solution method. In this example, the series is actually summed.