Wrinkling control of inflatable booms using shape memory alloy wires

An inflatable boom is a fundamental structural part of inflatable space structures maintaining the expected configuration of the whole system, supporting external loads and guaranteeing the efficiency of the membrane surface. The inflatable structure is a thin film structure compactly packaged and expanded to the desired configuration by the internal gas pressure. But the structures can be easily distorted and even collapsed by wrinkling. In this study, the behavior of an inflatable boom structure is investigated numerically and experimentally. To achieve a better bending strength, the methodology to control the wrinkling growth and the deformed configuration of the inflatable boom structure with a shape memory alloy (SMA) wire actuator is developed. To understand the nonlinear behavior of an inflatable boom due to wrinkling, the structure is numerically modeled using the ABAQUS finite element program with a wrinkling algorithm developed based on the Miller-Hedgepeth membrane theory. To verify the present analysis method, the inflatable boom made of Kapton film is examined by the bending tests with various internal pressures. To delay the growth of wrinkling that rapidly deteriorates the bending strength of the inflatable boom, a SMA wire actuator is applied. SMA wires are attached on the edge of the inflatable boom and generate a recovery force to remove wrinkling and restore the deformation of the boom.