Experiments to Test a Systems Analysis of Brittle Fracture.
Final technical rept.,
BATTELLE MEMORIAL INST COLUMBUS OHIO
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The aim of this program has been to simplify the complex problem of fracture of metals by a systems approach for a given type or mode of failure, the basic simple parameters and mechanisms controlling failure are identified, these are treated individually by experiment and analysis, and the individual results are combined into a description of the failure process yielding predictions which can be checked by experiment. Except for the last portion of the program, the experiments were conducted on center cracked steel foils. In the earlier stages of work the analysis concentrated on predictions of the development of plasticity with loading and the conditions at which crack propagation begins. The work was then directed toward the problem of rapid crack propagation basing the analysis on previous results. The work has yielded a detailed description of crack propagation under plane stress conditions both in the form of an analytic model and experimental observations of crack speeds. A method for quantitatively measuring the energy absorption rate of a material during crack propagation has been tested. This method holds promise as a way of characterizing the intrinsic resistance to unstable crack propagation. Some of the concepts and methods developed have been applied to the very complex problem of calculating crack speeds in pipelines. Author
- Metallurgy and Metallography