CRACK EXTENSION BY ALTERNATING SHEAR,

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Abstract:

A comparison of the slip line flow field at the tip of a sharp crack and of a blunted crack shows that a sharp crack can be extended by alternating shear until it becomes blunted. Crack tip blunting is associated with high strain concentration and fracture by hole growth and coalescence. Crack extension by alternating shear has been obtained in fully plastic, plane strain sharply notched, singly and doubly grooved tensile specimens. Electron fractography shows crack extension by alternating shear at the tip of cleavage and fatigue cracks. It is shown that fatigue crack propagation is the result of repeated cyclic crack extension by alternating shear. Author

Author(s):
Mcclintock, F. A. ; Pelloux, R. M. N.
Author Organization(s):
BOEING SCIENTIFIC RESEARCH LABS SEATTLE WASH SOLID STATE PHYSICS LAB
Supplementary Note:
Prepared in cooperation with Massachusetts Inst. of Tech., Cambridge. Materials Div.
Pagination:
0032

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
D1-82-0708
 Subject Terms
Communities of Interest:
Air Platforms
Descriptor(s):
(*CRACK PROPAGATION, ALLOYS), (*FRACTURE(MECHANICS), ALLOYS), SURFACE PROPERTIES, SHEAR STRESSES, DUCTILITY, RUPTURE, FATIGUE(MECHANICS), ALUMINUM ALLOYS, TITANIUM ALLOYS, STEEL, COPPER
Field(s)/Group(s):
Metallurgy and Metallography, Mechanics
Keyword(s):
ALUMINUM ALLOY 6061, ALUMINUM ALLOY 2024 T3, STEEL 4340
Report Date:
1968 Feb 01