J-integral studies of crack initiation and crack tip-blunting of phenolphthalein polyether ketone

✍ Scribed by Yanchun Han; Yuming Yang; Binyao Li; Zhiliu Feng

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 604 KB
• Volume: 54
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1994.070540312

✦ Synopsis

The J-integral is applied to characterize the fracture initiation of phenolphthalein polyether ketone (PEK-C ) for which the concepts of linear elastic fracture mechanics (LEFM) are inapplicable at high temperatures for reasonably-sized specimens due to extensive plasticity. The multiple-specimen resistance curve technique recommended by the ASTM is the basic method employed. The values of JIc increase with increasing temperature. The crack tipblunting of PEK-C is observed. The parameters, such as crack opening displacement (COD), 60, and the stretching increment Aabl are introduced to describe the blunting phenomenon. The 6o increases with increasing temperature, as does Aa,,. This indicates that the blunting occurs easily as the temperature increases; i.e., as the material's yield stress, a , steadily falls. The relationships between h0, Aabl, and uy are also discussed.