Enhanced buckling performance of a stiffened, variable angle tow thermoplastic composite panel

Variable stiffness composites are exciting emerging structures capable of improving structural performance through tailored load redistribution. This technology is particularly relevant to aerospace structures, such as aircraft wings, which rely on stressed skins to resist compressive, buckling loads. Variable Angle Tow (VAT) composite laminates manufactured via tow steering can increase buckling capacity of composite structures, leading to reduce material weight and costs. Numerical models have progressed to the point whereby this technology can be explored for complex aerospace structures. Further progress can be made through incorporating the latest manufacturing methods with simple and representative testing techniques to analyze buckling performance and benchmark numerical models. This work aims to analyze the buckling performance of a stiffened VAT panel using a novel test method. Laser assisted tape placement is used to manufacture the panel using thermoplastic composite tape, improving manufacturing accuracy and speed. The buckling response of this component is then tested using a newly developed three-point bending test method. The test method was designed using finite element models, experimentally validated, and the results were compared against a numerical model (based on the Ritz approach). It was found that the developed test can produce buckling in the skin, with the buckling mode matching that of the numerical model.