Analytical modelling of continuous fibre-reinforced thermoplastics’ thermomechanical properties and implementation into a failure model

Mechanical properties of fibre-reinforced thermoplastics show a remarkable temperature dependence within application temperatures of automotive and aerospace lightweight structures. To take this dependence into account when designing components, the strengths (, , , , ) and stiffnesses (, , , , ) of continuous carbon and glass fibre-reinforced polyamide 6 and glass fibre-reinforced polypropylene are modelled analytically based on experiments. Data from temperature-controlled tests on flat samples in the range from -20 °C to +80 °C are therefore approximated using an extended hyperbolic approach. The models obtained are then evaluated based on their deviation from the experimental values. The main criterion of this evaluation is the reliable prediction of the temperature-dependent material properties while minimising the effort for generating test data and determining model parameters. Furthermore, the failure behaviour of the investigated materials under multiaxial mechanical and thermal stress is examined by implementing the determined strength curves into Cuntze’s physically based failure criterion.