FATIGU3

The project is dedicated to investigating inter-fiber fractures (IFF) and delaminations as well as their influence on the stability behavior of fiber-reinforced polymers (FRP) under cyclic loading with load direction reversal. In high-performance FRP components in particular, cyclic stresses arise between tensile and compressive loading, with IFF acting as the initial damage mechanism. These fractures propagate, leading to delaminations and significantly impairing the structural stability. The objective of the project is to develop a deeper understanding of the interaction between IFF, delaminations, and stability failure (buckling), in order to better exploit the lightweight potential of FRP. Previous studies have largely treated damage and stability phenomena separately, even though their interaction is critical for the load-bearing capacity and resource efficiency of FRP structures. This requires experimental and numerical investigation of the damage evolution, including the development of models for simulating intralaminar and interlaminar damage mechanisms. To this end, established modeling approaches — such as continuum damage models and cohesive zone models — are to be further developed and adapted to cyclic loading scenarios. The project combines experimental investigations, such as transmitted-light photography for observing IFF and delaminations, with simulation-based approaches to accurately describe the stability behavior of complexly damaged FRP structures. The ultimate goal is to reduce material consumption and over-dimensioning by linking damage and stability analyses.