CRACK INITIATION IN METALLIC MATERIALS
Abstract
An attempt is made to show that all dislocation mechanism of crack formation proposed to date will lead to the formation of a microcrack which is approximately normal to the direction of the applied stress. This is due to the stress field at the tip of this primary initial crack which has a maximum stress concentration not at the center of the crack root but at the point where the tangent at the crack root is nearly parallel to the direction of the applied stress. This will lead to the formation of a secondary micro crack perpendicular to the direction of the applied stress as soon as a critical stress at the tip of the primary microcrack is reached. It is further shown that several mechanisms exist which may increase the radius of curvature at the tip of the crack. This would be associated with a marked decrease of the stress concentration factor. These mechanisms may therefore be re sponsible for the arrest of a propagating crack and the experimentally observed larger stress requirement for crack propagation than for crack initiation.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1963
- Accession Number
- AD0410372
Entities
People
- K. Schroder
- P. Packman
- V. Weiss