Influences of stress triaxiality and local fiber orientation on the failure strain for injection-molded carbon fiber reinforced polyamide-6

In this paper, the influence of the stress triaxiality on the failure strain of short fiber-reinforced composite, manufactured by the injection molding process, is investigated by tensile tests on notched ASTM-D638 specimen and ASTM E1820-01 U-Shape specimens made of a polyamide-6 thermoplastic polymer reinforced with 20% of short carbon fibers (PA6-20CF). From the combined experimental and FEA investigations, a function correlating the failure strain and the stress triaxiality has been developed can be utilized as a failure criterion for complex components made of short fibers reinforced polymers during the design stage, where no direct testing is a viable option.