STP803V2

    Some Salient Features of the Tearing Instability Theory

    Published: Jan 1983


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    Abstract

    In this work the problem of the stability of a system deformed under displacement and load-controlled conditions is examined. The instability conditions are found from the load versus displacements, P-δ, characteristics of the system and the stiffness of the structure, KM, on a completely general basis. The analysis is performed for the system in series with a spring under displacement control and for the system in parallel with the spring under load-controlled conditions.

    In addition it is shown that the conditions for instability found for both situations using the tearing instability theory are in complete agreement with those obtained under a completely general basis. As a result the tearing instability theory is proven to be always valid in the sense that instability will occur if and only if Tapp > Tmat.

    Finally, a small experimental program on a nickel-chromium-molybdenum-vanadium rotor steel was conducted in order to prove that structures can be designed to assure stable crack growth under load-controlled conditions beyond maximum load.

    Keywords:

    systems, instability, fracture, mechanics, plasticity, tearing, T, J, R-curves, load, displacement, elastic-plastic fracture


    Author Information:

    Ernst, HA
    Senior engineer, Westinghouse R&D Center, Pittsburgh, Pa.


    Paper ID: STP36765S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP36765S


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