THE ESSENTIAL WORK OF PLANE-STRESS DUCTILE FRACTURE OF LINEAR POLYETHYLENES

The specific essential works of plane stress ductile tearing of several high- and ultrahigh-molecular-weight polyethylenes were obtained from deeply edge-notched tension specimens, with either single or double notches, by extrapolating the straight line relationship between the total specific fracture work and ligament length to zero ligament. Provided the fracture morphologies of the torn ligament are not widely different, the specific essential work (w//e) is a material property dependent on thickness but independent of specimen geometry. The specific essential fracture work also can be identified with J//c, the critical value of the J-integral along a contour immediately bordering the fracture process zone at the crack tip. There is good agreement between the experimental w//e values and theoretical J//c estimates for these polyethylene materials.