Material Model Validation for Finite Element Simulations of Inflatable Structures

Developing ultra-lightweight, deployable, and adaptive systems has become a trend in aerospace and aeronautics over the last two decades. The incorporation of inflatable structures can produce significant advantages in stowed volume to mechanical effectiveness and overall weight for many aerospace systems [1-8]. Most inflatable systems are designed to precisely control both internal and external surfaces to achieve a desired response or structure. The dynamics and structure of inflatable systems is directly related to the configuration of interfacing boundaries. Designing new inflatable systems will be predicated on developing verified models of structures that comprise inflatable systems. The proposed efforts are an important foundation for future designs. The present project involves developing and verifying a material model for use in finite element modeling of an inflatable system. A proven double coated woven fabric has been chosen forall testing. Modeling woven fabrics is difficult due to the material nonlinearities caused by the microstructure of the fabric. For the proposed research a macroscopic approach will be taken to create the material model for the coated woven fabric. For validation of the material model, a triangular specimen will be used to perform various bi-axially tension tests. These tests will involve several clamping styles and manipulating the orientation of material properties. Simulations of these tests will be compared directly to experimental results for validation. Based upon results of this project, knowledge will be gained about key boundary conditions and material properties of inflatable systems.