A new nonlinear polyconvex orthotropic material model for the robust simulation of technical fabrics in civil engineering applications at large strains – Validation with large-scale experiment/Ein neues polykonvexes orthotropes Materialmodell zur robusten Simulation von Textilmembranen im Bauingenieur- wesen unter Berücksichtigung großer Deformationen – Validierung anhand eines Großbauteilversuchs

A polyconvex orthotropic material model is proposed for the simulation of tensile membrane structures. The notion of anisotropic metric tensors is employed in the formulation of the polyconvex orthotropic term which allows for the description of the interaction of the warp and fill yarns. The model is adjusted to the stress-strain paths of uni- and biaxial tensile tests of a woven fabric and the results are compared with the linear elastic model. The lateral contraction in the uniaxial loading case is taken into account to also capture the strong crosswise interactions. An increased number of load cycles is considered in the experiments to reach a saturated elastic state of the material. A new method is proposed enabling in principle the identification of unique (linear) stiffness parameters by previously identifying the (nonlinear) model parameters. Eventually, the proposed nonlinear model contains only 4 material parameters to be identified for the individual membrane material. Moreover, a new large-scale experimental setting is presented which allows for the validation of the proposed model response in real-life engineering applications. The numerical robustness of the model is tested in an advanced simulation of a large roof structure under application of realistic boundary conditions.