Strain rate dependent damage evolution in long glass fiber reinforced polypropylene

Strain rate dependent characterizations of glass fiber reinforced thermoplastic (LFT) under different multiaxialities show an increasing fracture strain and higher energy absorption capacity if the loading rate rises. The present paper gives a clue for the underlying micro-thermo-mechanical mechanisms of this effect. The method of correlating experimental field information of strain and heat generation provides data for advanced analysis. Strain and heat distribution of the deformation zone as well as a hot-spot occurrence display give hints on expanded damage zones at high strain rates. Quasi-static and dynamic interrupted tensile tests provided data to investigate the damage evolution. Scanning electron microscopic (SEM) images show differences in the area between fiber and matrix depending on the strain rate. Based on SEM images and correlated and analyzed field data a model representation was established that presents, in agreement with the literature, a perception of the damage mechanisms in the interface and its consequences for global deformation.