A study on fiber-arrangement close to the root of a sharp notch, for short fiber-reinforced thermoplastics

An approach, which aims at the morphological characterization near the sharp notch of specimens, has been developed for Short Fiber-Reinforced Thermoplastics. This work is directly related to the fa- tigue behavior of such materials, since the early stages of the cyclic damage are strictly influenced by the local microstructure at the stress concentration sites. Therefore, a comprehensive description of fi- bers’ arrangement is needed in order to proceed with a modeling activity for the lifetime duration esti- mation. To this end, a semi-automatic tool has been developed, which is capable of evaluating fiber- arrangements through statistical descriptors, after submitting 2D pictures of the notch-tip area. Particu- larly, the attention was focused onto the nearest neighbor distance distribution function and onto a new formulation, which gives information about the level of the fiber-clustering phenomenon. On this basis, the repeatability of results has been evaluated with the goal of stating whether such information can be inherited by lifetime estimating models.