Simulation of the damage mechanisms of glass fiber reinforced polypropylene based on micro specimens and 1:1 models of their microstructure

Fiber reinforced thermoplastics are considered as promising candidates to enable the mass production of lightweight components. To assure their structural application, precise methods to describe their mechanical behavior are mandatory. However, the modeling of the damage behavior of the thermoplastic matrix under multiaxial stress states within the microstructure still poses enormous challenges. In order to capture the in situ behavior of the matrix and the fiber-matrix interface, a novel methodology is applied in our work. Micro tensile specimens, which are manufactured from 100 μm thin slices of the material's cross section, are tested up to their failure. A corresponding finite element mesh which precisely depicts the individual microstructure of each specimen is reconstructed based on computer tomographic scans. Due to the dimensions of the specimens being sufficiently small, the position and orientation of each fiber can be directly mapped to the model. Micromech anical simulations are performed to separate the contributions of the matrix, the interface and the fibers to the global response of the specimens. It is shown that the stress-strain response of two specimens with a strongly different microstructure can be accurately captured by our simulations under application of the same material parameters. Furthermore, the damage evolution within the microstructure of the simulations and the experiments is visualized and compared.