ABSTRACT
Many composites consist of a fabric structure embedded in a matrix material. In the case of pneumatic membranes, the fibres are polyester threads which show noticeable plastic deformation. The stiffness of the fibres determines the overall stiffness of the material. The correct modelling of the orthotropy of the composite is therefore very important. In addition, the structure experiences large deformations which must be accounted for. Suitable models for this type of materials are therefore derived in the framework of finite anisotropic plasticity. A main problem is, however, the lack of experimental data in the literature. For this reason, a computer model of the composite is set up for numerical experiments. In this way, sufficient data can be generated. The present continuum mechanical model based on these “artificial” test data can be efficiently implemented into a finite element formulation. Using a special integration algorithm, the non-linear equation system consisting initially of ten equations reduces to two non-linear scalar equations.
