The objective of this paper is to investigate the applicability of an advanced ductile fracture mechanics method to polymeric materials. This method was originally proposed by Ernst and Landes. It has been further developed by the authors and successfully used to predict the behavior of various metallic structural components containing crack-like defects. The inputs needed for this method are calibration functions and fracture toughness. The calibration functions used here are based upon the load separation principle; the fracture toughness is given in terms of the J-R curve. A critical step in the method is the determination of the calibration functions. Two procedures for doing this are introduced in this paper. One is a transformation procedure that can be used to transfer the calibration function for a fracture toughness specimen to one for a structural component. The other is a numerically based one in which the deformation pattern is numerically simulated and the load separation method is applied to define the calibration parameters.
The materials used in this study include two polymers, a toughened nylon and a polycarbonate. The method is used to predict the load versus displacement for a nylon single-edge notched bend specimen and the compact specimens of the polycarbonate. The predictions are compared with the experimental results. It is shown that the ductile fracture method applies to these polymers. However, in the case where the material fracture toughness is strongly dependent on geometry and constraint, accurate prediction can only be ensured when the correct J-R curve is used.