Investigation of the fatigue behavior of notched reinforced thermoplastics

Understanding and modeling of fatigue damage and behavior in short glass fiber reinforced thermoplastics is an important issue in order to improve material processing and the design of composite parts for the industry. The present work aims at a more precise description of the fatigue damage mechanisms and the establishment of a simple, yet efficient, durability criterion. Observations bring new insights on the fatigue damage mechanisms: fiber failure triggered by fretting fatigue and crack propagation by intra-spherulitic failure in their equatorial plane. Finally, a cyclic strain rate criterion is introduced for notched specimens and the identification of a behavior model is performed for later implementation of the durability criterion.