Fracture load predictions in short glass fiber reinforced polyamide 6 U-notched specimens combining the equivalent material concept and the theory of critical distances

This article provides the prediction of fracture loads in single edge notched bending (SENB) specimens made of short glass fiber reinforced polyamide 6 (SGFR-PA6) and containing U-notches. The predictions are obtained through the combination of the equivalent material concept and the theory of critical distances (TCD). The latter is based on the material critical distance (L) and has a linear-elastic nature. This implies that in those materials exhibiting non-fully linear-elastic behavior, the determination of the material critical distance requires a calibration process that may be performed by fracture testing on notched specimens or through a combination of fracture testing and finite elements simulation. This represents a significant barrier for the application of the TCD on an industrial level. The proposed methodology defines an equivalent linear-elastic material on which the TCD may be applied through its basic formulation and without any previous calibration of the corresponding critical distance. It is applied to SGFR-PA6 SENB specimens, providing accurate predictions of the experimental fracture loads.