The methodology to restrain the growth of wrinkling region in inflatable boom is numerically and experimentally investigated. The inflatable boom structure is numerically modeled by using ABAQUS finite element program with membrane elements. To consider the nonlinear deformations of inflatable boom due to wrinkling, the numerical algorithm of wrinkling based on Miller-Hedgepeth membrane theory is developed using user defined material (UMAT) subroutine supported by ABAQUS. The experimental model of inflatable boom is made of Kapton film. To characterize the nonlinear behaviors of inflatable boom, the bending tests for various internal pressures are performed. To delay the growth of wrinkled region and restore the deformed shape of inflatable boom, shape memory alloy (SMA) wire actuator attached on surface of the structure is applied.
The interactions between the inflatable structure and shape memory alloy (SMA) strip actuators are investigated using finite element simulation. The numerical algorithm of the 3-D SMA thermomechanical constitutive equations based on Lagoudas model is implemented to analyze the unique characteristics of SMA strip. For the numerical results presented in this paper, the ABAQUS finite element program has been utilized with an appropriate user supplied subroutine (UMAT) for the modeling SMA strip. In this model of SMA strip, the shape memory effect is restricted to one-way applications. The geometrically nonlinear, updated Lagrangian equilibrium formulation implemented in ABAQUS is used for the numerical model of inflated membrane structures.