SEDL / STP / STP791-EB / STP37097S

Experimental Verification of Tearing Instability Phenomena for Structural Materials

Vassilaros, MG
Metallurgist and branch head, David Taylor Naval Ship Research and Development Center, Annapolis, Md.

Joyce, JA
Associate professor, U.S. Naval Academy, Annapolis, Md.

Gudas, JP
Metallurgist and branch head, David Taylor Naval Ship Research and Development Center, Annapolis, Md.

Pages: 19    Published: Jan 1983

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Abstract

The objective of this investigation was to extend the range of tearing instability validation experiments utilizing the compact specimen to include high-toughness alloys. J-integral (J^I) tests of ASTM A106, ASTM A516 GR70, HY-80, and HY-130 steels were performed in a variably compliant screw-driven test machine. Results were analyzed with respect to the J^I-R curves of the materials, and various models of T^applied for the compact specimen. Tearing instability theory was validated for these high-toughness materials. For the cases of highly curved J^I-R curves, it was shown that the actual value of T^material at the point of instability should be employed rather than the average T^material value. The T^applied analysis of Paris and co-workers applied to the compact specimen appears to be nonconservative in predicting the point of instability, whereas the T^applied analysis of Ernst and co-workers appears to be accurate, but requires precision beyond that displayed in this program. The generalized Paris analysis applied to the compact specimen and evaluated at maximum load was most consistent in predicting instability.