Meso-macro modelling of fibre-reinforced rubber-like composites exhibiting large elastoplastic deformation

Many composites consist of a fabric structure embedded in a matrix material. As an example, in the present paper, the case of pneumatic membranes is considered. Fibres are often made of material which shows noticeable plastic deformation. The stiffness of the fibres determines the overall stiffness of the material such that the correct modelling of the orthotropy of the composite is 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 10 equations reduces to two non-linear scalar equations.