A STUDY OF BRITTLE FRACTURE INITIATION IN MILD STEEL
The purpose of this investigation was to study the conditions of brittle-fracture initiation in low-carbon steel. An elastic-plastic stress analysis was developed from which the state of stress along the minimum section of a notched specimen could be determined as a function of the average applied stress and the yield stress. A series of tests on plate-type specimens, with the same notch configuration as that used in the stress analysis, provided experimental values of average fracture stress under various test conditions. Application of the elastic-plastic stress analysis to the experimental results provided a theoretical prediction of the state of stress at the instant and location of fracture initiation and also an indication of the position of the elastic-plastic boundary at fracture. It was found that the stress condition necessary for brittle fracture initiation, in the mild-steel specimens studied, was achieved when the maximum tensile stress reached a critical value of approximately 246,000 psi. For a ratio of average applied stress to yield stress above a certain value, the maximum tensile stress cannot attain the necessary stress value for the initiation of a brittle fracture as defined herein, and the resulting fracture will be ductile in nature, preceded by gross plastic deformation. Results from this investigation were compared with existing information related to fracture initiation to provide a basis for evaluating both the analytical technique employed and the final results obtained.
University of Illinois, Urbana-ChampaignUrbana, IL United States 61801
Ship Structure CommitteeNational Academy of Science, 2101 Constitution Avenue, NW
Washington, DC United States 20418
- Barton, F W
- Hall, W J
- Publication Date: 1963-7-15
- Features: References;
- Pagination: 30 p.
- TRT Terms: Cracking; Elastoplasticity; Fracture mechanics; Notch tests
- Identifier Terms: Ship Structure Committee
- Uncontrolled Terms: Crack initiation
- Subject Areas: Marine Transportation; Materials;
- Accession Number: 00331929
- Record Type: Publication
- Source Agency: Ship Structure Committee
- Report/Paper Numbers: SSC-147 Tech Rpt.
- Contract Numbers: NObs-65790, NObs-84321
- Files: TRIS
- Created Date: May 21 1981 12:00AM